Auto merge of #2762 - RalfJung:rustup, r=RalfJung

Rustup

703 files changed, 10302 insertions, 5405 deletions

diff --git a/.mailmap b/.mailmap
index 022cdd0fd50..42c86a82769 100644
--- a/.mailmap
+++ b/.mailmap
@@ -15,6 +15,7 @@ Adrien Tétar <adri-from-59@hotmail.fr>
 Ahmed Charles <ahmedcharles@gmail.com> <acharles@outlook.com>
 Alan Egerton <eggyal@gmail.com>
 Alan Stoate <alan.stoate@gmail.com>
+Albert Larsan <albert.larsan@gmail.com> Albert Larsan <74931857+albertlarsan68@users.noreply.github.com>
 Alessandro Decina <alessandro.d@gmail.com>
 Alex Burka <durka42+github@gmail.com> Alex Burka <aburka@seas.upenn.edu>
 Alex Hansen <ahansen2@trinity.edu>
diff --git a/Cargo.lock b/Cargo.lock
index 5511d301775..cc1b5dcf6a7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -351,7 +351,7 @@ dependencies = [
  "cargo-test-macro",
  "cargo-test-support",
  "cargo-util",
- "clap 4.0.32",
+ "clap 4.1.1",
  "crates-io",
  "curl",
  "curl-sys",
@@ -551,9 +551,9 @@ version = "0.1.0"
 
 [[package]]
 name = "cc"
-version = "1.0.76"
+version = "1.0.77"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "76a284da2e6fe2092f2353e51713435363112dfd60030e22add80be333fb928f"
+checksum = "e9f73505338f7d905b19d18738976aae232eb46b8efc15554ffc56deb5d9ebe4"
 dependencies = [
  "jobserver",
 ]
@@ -655,12 +655,12 @@ dependencies = [
 
 [[package]]
 name = "clap"
-version = "4.0.32"
+version = "4.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "a7db700bc935f9e43e88d00b0850dae18a63773cfbec6d8e070fccf7fef89a39"
+checksum = "4ec7a4128863c188deefe750ac1d1dfe66c236909f845af04beed823638dc1b2"
 dependencies = [
  "bitflags",
- "clap_derive 4.0.21",
+ "clap_derive 4.1.0",
  "clap_lex 0.3.0",
  "is-terminal",
  "once_cell",
@@ -675,7 +675,7 @@ version = "4.0.7"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "10861370d2ba66b0f5989f83ebf35db6421713fd92351790e7fdd6c36774c56b"
 dependencies = [
- "clap 4.0.32",
+ "clap 4.1.1",
 ]
 
 [[package]]
@@ -693,9 +693,9 @@ dependencies = [
 
 [[package]]
 name = "clap_derive"
-version = "4.0.21"
+version = "4.1.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0177313f9f02afc995627906bbd8967e2be069f5261954222dac78290c2b9014"
+checksum = "684a277d672e91966334af371f1a7b5833f9aa00b07c84e92fbce95e00208ce8"
 dependencies = [
  "heck",
  "proc-macro-error",
@@ -1799,9 +1799,9 @@ dependencies = [
 
 [[package]]
 name = "git2"
-version = "0.16.0"
+version = "0.16.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "be36bc9e0546df253c0cc41fd0af34f5e92845ad8509462ec76672fac6997f5b"
+checksum = "ccf7f68c2995f392c49fffb4f95ae2c873297830eb25c6bc4c114ce8f4562acc"
 dependencies = [
  "bitflags",
  "libc",
@@ -2294,7 +2294,7 @@ name = "jsondoclint"
 version = "0.1.0"
 dependencies = [
  "anyhow",
- "clap 4.0.32",
+ "clap 4.1.1",
  "fs-err",
  "rustdoc-json-types",
  "serde",
@@ -2365,9 +2365,9 @@ dependencies = [
 
 [[package]]
 name = "libgit2-sys"
-version = "0.14.1+1.5.0"
+version = "0.14.2+1.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "4a07fb2692bc3593bda59de45a502bb3071659f2c515e28c71e728306b038e17"
+checksum = "7f3d95f6b51075fe9810a7ae22c7095f12b98005ab364d8544797a825ce946a4"
 dependencies = [
  "cc",
  "libc",
@@ -2557,7 +2557,7 @@ dependencies = [
  "ammonia",
  "anyhow",
  "chrono",
- "clap 4.0.32",
+ "clap 4.1.1",
  "clap_complete",
  "elasticlunr-rs",
  "env_logger 0.10.0",
@@ -3528,7 +3528,7 @@ dependencies = [
 name = "rustbook"
 version = "0.1.0"
 dependencies = [
- "clap 4.0.32",
+ "clap 4.1.1",
  "env_logger 0.7.1",
  "mdbook",
 ]
@@ -4783,6 +4783,7 @@ dependencies = [
  "rustc_middle",
  "rustc_parse_format",
  "rustc_query_system",
+ "rustc_serialize",
  "rustc_session",
  "rustc_span",
  "rustc_target",
@@ -5607,6 +5608,7 @@ dependencies = [
  "lazy_static",
  "miropt-test-tools",
  "regex",
+ "semver",
  "termcolor",
  "walkdir",
 ]
diff --git a/README.md b/README.md
index ac39435a8c7..0eb7c4b266a 100644
--- a/README.md
+++ b/README.md
@@ -3,10 +3,11 @@
 This is the main source code repository for [Rust]. It contains the compiler,
 standard library, and documentation.
 
-[Rust]: https://www.rust-lang.org
+[Rust]: https://www.rust-lang.org/
 
 **Note: this README is for _users_ rather than _contributors_.**
-If you wish to _contribute_ to the compiler, you should read [CONTRIBUTING.md](CONTRIBUTING.md) instead.
+If you wish to _contribute_ to the compiler, you should read
+[CONTRIBUTING.md](CONTRIBUTING.md) instead.
 
 ## Quick Start
 
@@ -20,13 +21,15 @@ Read ["Installation"] from [The Book].
 The Rust build system uses a Python script called `x.py` to build the compiler,
 which manages the bootstrapping process. It lives at the root of the project.
 
-The `x.py` command can be run directly on most Unix systems in the following format:
+The `x.py` command can be run directly on most Unix systems in the following
+format:
 
 ```sh
 ./x.py <subcommand> [flags]
 ```
 
-This is how the documentation and examples assume you are running `x.py`. Some alternative ways are:
+This is how the documentation and examples assume you are running `x.py`.
+Some alternative ways are:
 
 ```sh
 # On a Unix shell if you don't have the necessary `python3` command
@@ -39,8 +42,8 @@ x.py <subcommand> [flags]
 python x.py <subcommand> [flags]
 ```
 
-More information about `x.py` can be found
-by running it with the `--help` flag or reading the [rustc dev guide][rustcguidebuild].
+More information about `x.py` can be found by running it with the `--help` flag
+or reading the [rustc dev guide][rustcguidebuild].
 
 [gettingstarted]: https://rustc-dev-guide.rust-lang.org/getting-started.html
 [rustcguidebuild]: https://rustc-dev-guide.rust-lang.org/building/how-to-build-and-run.html
@@ -49,24 +52,29 @@ by running it with the `--help` flag or reading the [rustc dev guide][rustcguide
 
 Make sure you have installed the dependencies:
 
-   * `python` 3 or 2.7
-   * `git`
-   * A C compiler (when building for the host, `cc` is enough; cross-compiling may need additional compilers)
-   * `curl` (not needed on Windows)
-   * `pkg-config` if you are compiling on Linux and targeting Linux
-   * `libiconv` (already included with glibc on Debian-based distros)
+* `python` 3 or 2.7
+* `git`
+* A C compiler (when building for the host, `cc` is enough; cross-compiling may
+  need additional compilers)
+* `curl` (not needed on Windows)
+* `pkg-config` if you are compiling on Linux and targeting Linux
+* `libiconv` (already included with glibc on Debian-based distros)
 
-To build cargo, you'll also need OpenSSL (`libssl-dev` or `openssl-devel` on most Unix distros).
+To build Cargo, you'll also need OpenSSL (`libssl-dev` or `openssl-devel` on
+most Unix distros).
 
 If building LLVM from source, you'll need additional tools:
 
 * `g++`, `clang++`, or MSVC with versions listed on
   [LLVM's documentation](https://llvm.org/docs/GettingStarted.html#host-c-toolchain-both-compiler-and-standard-library)
-* `ninja`, or GNU `make` 3.81 or later (ninja is recommended, especially on Windows)
+* `ninja`, or GNU `make` 3.81 or later (Ninja is recommended, especially on
+  Windows)
 * `cmake` 3.13.4 or later
-* `libstdc++-static` may be required on some Linux distributions such as Fedora and Ubuntu
+* `libstdc++-static` may be required on some Linux distributions such as Fedora
+  and Ubuntu
 
-On tier 1 or tier 2 with host tools platforms, you can also choose to download LLVM by setting `llvm.download-ci-llvm = true`.
+On tier 1 or tier 2 with host tools platforms, you can also choose to download
+LLVM by setting `llvm.download-ci-llvm = true`.
 Otherwise, you'll need LLVM installed and `llvm-config` in your path.
 See [the rustc-dev-guide for more info][sysllvm].
 
@@ -86,34 +94,37 @@ See [the rustc-dev-guide for more info][sysllvm].
 
 2. Configure the build settings:
 
-    The Rust build system uses a file named `config.toml` in the root of the
-    source tree to determine various configuration settings for the build.
-    Set up the defaults intended for distros to get started. You can see a full list of options
-    in `config.toml.example`.
+   The Rust build system uses a file named `config.toml` in the root of the
+   source tree to determine various configuration settings for the build.
+   Set up the defaults intended for distros to get started. You can see a full
+   list of options in `config.toml.example`.
 
-    ```sh
-    printf 'profile = "user" \nchangelog-seen = 2 \n' > config.toml
-    ```
+   ```sh
+   printf 'profile = "user" \nchangelog-seen = 2 \n' > config.toml
+   ```
 
-    If you plan to use `x.py install` to create an installation, it is recommended
-    that you set the `prefix` value in the `[install]` section to a directory.
+   If you plan to use `x.py install` to create an installation, it is
+   recommended that you set the `prefix` value in the `[install]` section to a
+   directory.
 
 3. Build and install:
 
-    ```sh
-    ./x.py build && ./x.py install
-    ```
+   ```sh
+   ./x.py build && ./x.py install
+   ```
 
-    When complete, `./x.py install` will place several programs into
-    `$PREFIX/bin`: `rustc`, the Rust compiler, and `rustdoc`, the
-    API-documentation tool. If you've set `profile = "user"` or `build.extended = true`, it will
-    also include [Cargo], Rust's package manager.
+   When complete, `./x.py install` will place several programs into
+   `$PREFIX/bin`: `rustc`, the Rust compiler, and `rustdoc`, the
+   API-documentation tool. If you've set `profile = "user"` or
+   `build.extended = true`, it will also include [Cargo], Rust's package
+   manager.
 
 [Cargo]: https://github.com/rust-lang/cargo
 
 ### Building on Windows
 
-On Windows, we suggest using [winget] to install dependencies by running the following in a terminal:
+On Windows, we suggest using [winget] to install dependencies by running the
+following in a terminal:
 
 ```powershell
 winget install -e Python.Python.3
@@ -121,17 +132,19 @@ winget install -e Kitware.CMake
 winget install -e Git.Git
 ```
 
-Then edit your system's `PATH` variable and add: `C:\Program Files\CMake\bin`. See
-[this guide on editing the system `PATH`](https://www.java.com/en/download/help/path.html) from the
-Java documentation.
+Then edit your system's `PATH` variable and add: `C:\Program Files\CMake\bin`.
+See
+[this guide on editing the system `PATH`](https://www.java.com/en/download/help/path.html)
+from the Java documentation.
 
 [winget]: https://github.com/microsoft/winget-cli
 
 There are two prominent ABIs in use on Windows: the native (MSVC) ABI used by
 Visual Studio and the GNU ABI used by the GCC toolchain. Which version of Rust
 you need depends largely on what C/C++ libraries you want to interoperate with.
-Use the MSVC build of Rust to interop with software produced by Visual Studio and
-the GNU build to interop with GNU software built using the MinGW/MSYS2 toolchain.
+Use the MSVC build of Rust to interop with software produced by Visual Studio
+and the GNU build to interop with GNU software built using the MinGW/MSYS2
+toolchain.
 
 #### MinGW
 
@@ -144,7 +157,7 @@ the GNU build to interop with GNU software built using the MinGW/MSYS2 toolchain
 2. Run `mingw32_shell.bat` or `mingw64_shell.bat` from the MSYS2 installation
    directory (e.g. `C:\msys64`), depending on whether you want 32-bit or 64-bit
    Rust. (As of the latest version of MSYS2 you have to run `msys2_shell.cmd
-   -mingw32` or `msys2_shell.cmd -mingw64` from the command line instead)
+   -mingw32` or `msys2_shell.cmd -mingw64` from the command line instead.)
 
 3. From this terminal, install the required tools:
 
@@ -153,11 +166,11 @@ the GNU build to interop with GNU software built using the MinGW/MSYS2 toolchain
    pacman -Sy pacman-mirrors
 
    # Install build tools needed for Rust. If you're building a 32-bit compiler,
-   # then replace "x86_64" below with "i686". If you've already got git, python,
-   # or CMake installed and in PATH you can remove them from this list. Note
-   # that it is important that you do **not** use the 'python2', 'cmake' and 'ninja'
-   # packages from the 'msys2' subsystem. The build has historically been known
-   # to fail with these packages.
+   # then replace "x86_64" below with "i686". If you've already got Git, Python,
+   # or CMake installed and in PATH you can remove them from this list.
+   # Note that it is important that you do **not** use the 'python2', 'cmake',
+   # and 'ninja' packages from the 'msys2' subsystem.
+   # The build has historically been known to fail with these packages.
    pacman -S git \
                make \
                diffutils \
@@ -178,12 +191,12 @@ the GNU build to interop with GNU software built using the MinGW/MSYS2 toolchain
 
 MSVC builds of Rust additionally require an installation of Visual Studio 2017
 (or later) so `rustc` can use its linker.  The simplest way is to get
-[Visual Studio], check the “C++ build tools” and “Windows 10 SDK” workload.
+[Visual Studio], check the "C++ build tools" and "Windows 10 SDK" workload.
 
 [Visual Studio]: https://visualstudio.microsoft.com/downloads/
 
-(If you're installing cmake yourself, be careful that “C++ CMake tools for
-Windows” doesn't get included under “Individual components”.)
+(If you're installing CMake yourself, be careful that "C++ CMake tools for
+Windows" doesn't get included under "Individual components".)
 
 With these dependencies installed, you can build the compiler in a `cmd.exe`
 shell with:
@@ -192,10 +205,11 @@ shell with:
 python x.py build
 ```
 
-Right now, building Rust only works with some known versions of Visual Studio. If
-you have a more recent version installed and the build system doesn't understand,
-you may need to force rustbuild to use an older version. This can be done
-by manually calling the appropriate vcvars file before running the bootstrap.
+Right now, building Rust only works with some known versions of Visual Studio.
+If you have a more recent version installed and the build system doesn't
+understand, you may need to force rustbuild to use an older version.
+This can be done by manually calling the appropriate vcvars file before running
+the bootstrap.
 
 ```batch
 CALL "C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"
@@ -215,9 +229,9 @@ Windows build triples are:
     - `x86_64-pc-windows-msvc`
 
 The build triple can be specified by either specifying `--build=<triple>` when
-invoking `x.py` commands, or by creating a `config.toml` file (as described
-in [Installing From Source](#installing-from-source)), and modifying the
-`build` option under the `[build]` section.
+invoking `x.py` commands, or by creating a `config.toml` file (as described in
+[Installing from Source](#installing-from-source)), and modifying the `build`
+option under the `[build]` section.
 
 ### Configure and Make
 
@@ -229,33 +243,35 @@ configure script and makefile (the latter of which just invokes `x.py`).
 make && sudo make install
 ```
 
-`configure` generates a `config.toml` which can also be used with normal `x.py` invocations.
+`configure` generates a `config.toml` which can also be used with normal `x.py`
+invocations.
 
 ## Building Documentation
 
-If you’d like to build the documentation, it’s almost the same:
+If you'd like to build the documentation, it's almost the same:
 
 ```sh
 ./x.py doc
 ```
 
 The generated documentation will appear under `doc` in the `build` directory for
-the ABI used. I.e., if the ABI was `x86_64-pc-windows-msvc`, the directory will be
-`build\x86_64-pc-windows-msvc\doc`.
+the ABI used. That is, if the ABI was `x86_64-pc-windows-msvc`, the directory
+will be `build\x86_64-pc-windows-msvc\doc`.
 
 ## Notes
 
-Since the Rust compiler is written in Rust, it must be built by a
-precompiled "snapshot" version of itself (made in an earlier stage of
-development). As such, source builds require an Internet connection to
-fetch snapshots, and an OS that can execute the available snapshot binaries.
+Since the Rust compiler is written in Rust, it must be built by a precompiled
+"snapshot" version of itself (made in an earlier stage of development).
+As such, source builds require an Internet connection to fetch snapshots, and an
+OS that can execute the available snapshot binaries.
 
-See https://doc.rust-lang.org/nightly/rustc/platform-support.html for a list of supported platforms.
-Only "host tools" platforms have a pre-compiled snapshot binary available; to compile for a platform
-without host tools you must cross-compile.
+See https://doc.rust-lang.org/nightly/rustc/platform-support.html for a list of
+supported platforms.
+Only "host tools" platforms have a pre-compiled snapshot binary available; to
+compile for a platform without host tools you must cross-compile.
 
-You may find that other platforms work, but these are our officially
-supported build environments that are most likely to work.
+You may find that other platforms work, but these are our officially supported
+build environments that are most likely to work.
 
 ## Getting Help
 
@@ -267,9 +283,9 @@ See [CONTRIBUTING.md](CONTRIBUTING.md).
 
 ## License
 
-Rust is primarily distributed under the terms of both the MIT license
-and the Apache License (Version 2.0), with portions covered by various
-BSD-like licenses.
+Rust is primarily distributed under the terms of both the MIT license and the
+Apache License (Version 2.0), with portions covered by various BSD-like
+licenses.
 
 See [LICENSE-APACHE](LICENSE-APACHE), [LICENSE-MIT](LICENSE-MIT), and
 [COPYRIGHT](COPYRIGHT) for details.
@@ -277,13 +293,14 @@ See [LICENSE-APACHE](LICENSE-APACHE), [LICENSE-MIT](LICENSE-MIT), and
 ## Trademark
 
 [The Rust Foundation][rust-foundation] owns and protects the Rust and Cargo
-trademarks and logos (the “Rust Trademarks”).
+trademarks and logos (the "Rust Trademarks").
 
-If you want to use these names or brands, please read the [media guide][media-guide].
+If you want to use these names or brands, please read the
+[media guide][media-guide].
 
 Third-party logos may be subject to third-party copyrights and trademarks. See
 [Licenses][policies-licenses] for details.
 
 [rust-foundation]: https://foundation.rust-lang.org/
-[media-guide]: https://www.rust-lang.org/policies/media-guide
+[media-guide]: https://foundation.rust-lang.org/policies/logo-policy-and-media-guide/
 [policies-licenses]: https://www.rust-lang.org/policies/licenses
diff --git a/compiler/rustc_ast/src/ast.rs b/compiler/rustc_ast/src/ast.rs
index 7de594719dd..9317579f70d 100644
--- a/compiler/rustc_ast/src/ast.rs
+++ b/compiler/rustc_ast/src/ast.rs
@@ -2032,7 +2032,8 @@ impl Clone for Ty {
 impl Ty {
     pub fn peel_refs(&self) -> &Self {
         let mut final_ty = self;
-        while let TyKind::Ref(_, MutTy { ty, .. }) = &final_ty.kind {
+        while let TyKind::Ref(_, MutTy { ty, .. }) | TyKind::Ptr(MutTy { ty, .. }) = &final_ty.kind
+        {
             final_ty = ty;
         }
         final_ty
diff --git a/compiler/rustc_ast_passes/src/ast_validation.rs b/compiler/rustc_ast_passes/src/ast_validation.rs
index 55ea12d25ea..902b4b1a1ec 100644
--- a/compiler/rustc_ast_passes/src/ast_validation.rs
+++ b/compiler/rustc_ast_passes/src/ast_validation.rs
@@ -1100,16 +1100,17 @@ impl<'a> Visitor<'a> for AstValidator<'a> {
                         replace_span: self.ending_semi_or_hi(item.span),
                         extern_block_suggestion: match sig.header.ext {
                             Extern::None => None,
-                            Extern::Implicit(start_span) => Some(ExternBlockSuggestion {
+                            Extern::Implicit(start_span) => Some(ExternBlockSuggestion::Implicit {
                                 start_span,
                                 end_span: item.span.shrink_to_hi(),
-                                abi: None,
-                            }),
-                            Extern::Explicit(abi, start_span) => Some(ExternBlockSuggestion {
-                                start_span,
-                                end_span: item.span.shrink_to_hi(),
-                                abi: Some(abi.symbol_unescaped),
                             }),
+                            Extern::Explicit(abi, start_span) => {
+                                Some(ExternBlockSuggestion::Explicit {
+                                    start_span,
+                                    end_span: item.span.shrink_to_hi(),
+                                    abi: abi.symbol_unescaped,
+                                })
+                            }
                         },
                     });
                 }
diff --git a/compiler/rustc_ast_passes/src/errors.rs b/compiler/rustc_ast_passes/src/errors.rs
index 59f582f10d9..09e262452b1 100644
--- a/compiler/rustc_ast_passes/src/errors.rs
+++ b/compiler/rustc_ast_passes/src/errors.rs
@@ -1,6 +1,5 @@
 //! Errors emitted by ast_passes.
 
-use rustc_errors::{fluent, AddToDiagnostic, Applicability, Diagnostic, SubdiagnosticMessage};
 use rustc_macros::{Diagnostic, Subdiagnostic};
 use rustc_span::{Span, Symbol};
 
@@ -207,28 +206,21 @@ pub struct FnWithoutBody {
     pub extern_block_suggestion: Option<ExternBlockSuggestion>,
 }
 
-pub struct ExternBlockSuggestion {
-    pub start_span: Span,
-    pub end_span: Span,
-    pub abi: Option<Symbol>,
-}
-
-impl AddToDiagnostic for ExternBlockSuggestion {
-    fn add_to_diagnostic_with<F>(self, diag: &mut Diagnostic, _: F)
-    where
-        F: Fn(&mut Diagnostic, SubdiagnosticMessage) -> SubdiagnosticMessage,
-    {
-        let start_suggestion = if let Some(abi) = self.abi {
-            format!("extern \"{}\" {{", abi)
-        } else {
-            "extern {".to_owned()
-        };
-        let end_suggestion = " }".to_owned();
-
-        diag.multipart_suggestion(
-            fluent::extern_block_suggestion,
-            vec![(self.start_span, start_suggestion), (self.end_span, end_suggestion)],
-            Applicability::MaybeIncorrect,
-        );
-    }
+#[derive(Subdiagnostic)]
+pub enum ExternBlockSuggestion {
+    #[multipart_suggestion(ast_passes_extern_block_suggestion, applicability = "maybe-incorrect")]
+    Implicit {
+        #[suggestion_part(code = "extern {{")]
+        start_span: Span,
+        #[suggestion_part(code = " }}")]
+        end_span: Span,
+    },
+    #[multipart_suggestion(ast_passes_extern_block_suggestion, applicability = "maybe-incorrect")]
+    Explicit {
+        #[suggestion_part(code = "extern \"{abi}\" {{")]
+        start_span: Span,
+        #[suggestion_part(code = " }}")]
+        end_span: Span,
+        abi: Symbol,
+    },
 }
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index 968c1f49b95..e5a36259fa4 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -673,40 +673,34 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let tcx = self.infcx.tcx;
 
         // Find out if the predicates show that the type is a Fn or FnMut
-        let find_fn_kind_from_did = |predicates: ty::EarlyBinder<
-            &[(ty::Predicate<'tcx>, Span)],
-        >,
-                                     substs| {
-            predicates.0.iter().find_map(|(pred, _)| {
-                    let pred = if let Some(substs) = substs {
-                        predicates.rebind(*pred).subst(tcx, substs).kind().skip_binder()
-                    } else {
-                        pred.kind().skip_binder()
-                    };
-                    if let ty::PredicateKind::Clause(ty::Clause::Trait(pred)) = pred && pred.self_ty() == ty {
-                    if Some(pred.def_id()) == tcx.lang_items().fn_trait() {
-                        return Some(hir::Mutability::Not);
-                    } else if Some(pred.def_id()) == tcx.lang_items().fn_mut_trait() {
-                        return Some(hir::Mutability::Mut);
-                    }
+        let find_fn_kind_from_did = |(pred, _): (ty::Predicate<'tcx>, _)| {
+            if let ty::PredicateKind::Clause(ty::Clause::Trait(pred)) = pred.kind().skip_binder()
+                && pred.self_ty() == ty
+            {
+                if Some(pred.def_id()) == tcx.lang_items().fn_trait() {
+                    return Some(hir::Mutability::Not);
+                } else if Some(pred.def_id()) == tcx.lang_items().fn_mut_trait() {
+                    return Some(hir::Mutability::Mut);
                 }
-                    None
-                })
+            }
+            None
         };
 
         // If the type is opaque/param/closure, and it is Fn or FnMut, let's suggest (mutably)
         // borrowing the type, since `&mut F: FnMut` iff `F: FnMut` and similarly for `Fn`.
         // These types seem reasonably opaque enough that they could be substituted with their
         // borrowed variants in a function body when we see a move error.
-        let borrow_level = match ty.kind() {
-            ty::Param(_) => find_fn_kind_from_did(
-                tcx.bound_explicit_predicates_of(self.mir_def_id().to_def_id())
-                    .map_bound(|p| p.predicates),
-                None,
-            ),
-            ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
-                find_fn_kind_from_did(tcx.bound_explicit_item_bounds(*def_id), Some(*substs))
-            }
+        let borrow_level = match *ty.kind() {
+            ty::Param(_) => tcx
+                .explicit_predicates_of(self.mir_def_id().to_def_id())
+                .predicates
+                .iter()
+                .copied()
+                .find_map(find_fn_kind_from_did),
+            ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => tcx
+                .bound_explicit_item_bounds(def_id)
+                .subst_iter_copied(tcx, substs)
+                .find_map(find_fn_kind_from_did),
             ty::Closure(_, substs) => match substs.as_closure().kind() {
                 ty::ClosureKind::Fn => Some(hir::Mutability::Not),
                 ty::ClosureKind::FnMut => Some(hir::Mutability::Mut),
@@ -2199,7 +2193,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
         let mut back_edge_stack = Vec::new();
 
         predecessor_locations(self.body, location).for_each(|predecessor| {
-            if location.dominates(predecessor, &self.dominators) {
+            if location.dominates(predecessor, self.dominators()) {
                 back_edge_stack.push(predecessor)
             } else {
                 stack.push(predecessor);
@@ -2311,7 +2305,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
             let mut has_predecessor = false;
             predecessor_locations(self.body, location).for_each(|predecessor| {
-                if location.dominates(predecessor, &self.dominators) {
+                if location.dominates(predecessor, self.dominators()) {
                     back_edge_stack.push(predecessor)
                 } else {
                     stack.push(predecessor);
diff --git a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
index f3050a6ef3f..187861ba127 100644
--- a/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/region_errors.rs
@@ -5,8 +5,13 @@
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_errors::{Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan};
 use rustc_hir as hir;
+use rustc_hir::def::Res::Def;
 use rustc_hir::def_id::DefId;
 use rustc_hir::intravisit::Visitor;
+use rustc_hir::GenericBound::Trait;
+use rustc_hir::QPath::Resolved;
+use rustc_hir::WherePredicate::BoundPredicate;
+use rustc_hir::{PolyTraitRef, TyKind, WhereBoundPredicate};
 use rustc_infer::infer::{
     error_reporting::nice_region_error::{
         self, find_anon_type, find_param_with_region, suggest_adding_lifetime_params,
@@ -186,6 +191,101 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
         false
     }
 
+    // For generic associated types (GATs) which implied 'static requirement
+    // from higher-ranked trait bounds (HRTB). Try to locate span of the trait
+    // and the span which bounded to the trait for adding 'static lifetime suggestion
+    fn suggest_static_lifetime_for_gat_from_hrtb(
+        &self,
+        diag: &mut DiagnosticBuilder<'_, ErrorGuaranteed>,
+        lower_bound: RegionVid,
+    ) {
+        let mut suggestions = vec![];
+        let hir = self.infcx.tcx.hir();
+
+        // find generic associated types in the given region 'lower_bound'
+        let gat_id_and_generics = self
+            .regioncx
+            .placeholders_contained_in(lower_bound)
+            .map(|placeholder| {
+                if let Some(id) = placeholder.name.get_id()
+                    && let Some(placeholder_id) = id.as_local()
+                    && let gat_hir_id = hir.local_def_id_to_hir_id(placeholder_id)
+                    && let Some(generics_impl) = hir.get_parent(gat_hir_id).generics()
+                {
+                    Some((gat_hir_id, generics_impl))
+                } else {
+                    None
+                }
+            })
+            .collect::<Vec<_>>();
+        debug!(?gat_id_and_generics);
+
+        // find higher-ranked trait bounds bounded to the generic associated types
+        let mut hrtb_bounds = vec![];
+        gat_id_and_generics.iter().flatten().for_each(|(gat_hir_id, generics)| {
+            for pred in generics.predicates {
+                let BoundPredicate(
+                        WhereBoundPredicate {
+                            bound_generic_params,
+                            bounds,
+                            ..
+                        }) = pred else { continue; };
+                if bound_generic_params
+                    .iter()
+                    .rfind(|bgp| hir.local_def_id_to_hir_id(bgp.def_id) == *gat_hir_id)
+                    .is_some()
+                {
+                    for bound in *bounds {
+                        hrtb_bounds.push(bound);
+                    }
+                }
+            }
+        });
+        debug!(?hrtb_bounds);
+
+        hrtb_bounds.iter().for_each(|bound| {
+            let Trait(PolyTraitRef { trait_ref, span: trait_span, .. }, _) = bound else { return; };
+            diag.span_note(
+                *trait_span,
+                format!("due to current limitations in the borrow checker, this implies a `'static` lifetime")
+            );
+            let Some(generics_fn) = hir.get_generics(self.body.source.def_id().expect_local()) else { return; };
+            let Def(_, trait_res_defid) = trait_ref.path.res else { return; };
+            debug!(?generics_fn);
+            generics_fn.predicates.iter().for_each(|predicate| {
+                let BoundPredicate(
+                    WhereBoundPredicate {
+                        span: bounded_span,
+                        bounded_ty,
+                        bounds,
+                        ..
+                    }
+                ) = predicate else { return; };
+                bounds.iter().for_each(|bd| {
+                    if let Trait(PolyTraitRef { trait_ref: tr_ref, .. }, _) = bd
+                        && let Def(_, res_defid) = tr_ref.path.res
+                        && res_defid == trait_res_defid // trait id matches
+                        && let TyKind::Path(Resolved(_, path)) = bounded_ty.kind
+                        && let Def(_, defid) = path.res
+                        && generics_fn.params
+                            .iter()
+                            .rfind(|param| param.def_id.to_def_id() == defid)
+                            .is_some() {
+                            suggestions.push((bounded_span.shrink_to_hi(), format!(" + 'static")));
+                        }
+                });
+            });
+        });
+        if suggestions.len() > 0 {
+            suggestions.dedup();
+            diag.multipart_suggestion_verbose(
+                format!("consider restricting the type parameter to the `'static` lifetime"),
+                suggestions,
+                Applicability::MaybeIncorrect,
+            );
+        }
+    }
+
     /// Produces nice borrowck error diagnostics for all the errors collected in `nll_errors`.
     pub(crate) fn report_region_errors(&mut self, nll_errors: RegionErrors<'tcx>) {
         // Iterate through all the errors, producing a diagnostic for each one. The diagnostics are
@@ -223,12 +323,21 @@ impl<'a, 'tcx> MirBorrowckCtxt<'a, 'tcx> {
                         // to report it; we could probably handle it by
                         // iterating over the universal regions and reporting
                         // an error that multiple bounds are required.
-                        self.buffer_error(self.infcx.tcx.sess.create_err(
-                            GenericDoesNotLiveLongEnough {
+                        let mut diag =
+                            self.infcx.tcx.sess.create_err(GenericDoesNotLiveLongEnough {
                                 kind: type_test.generic_kind.to_string(),
                                 span: type_test_span,
-                            },
-                        ));
+                            });
+
+                        // Add notes and suggestions for the case of 'static lifetime
+                        // implied but not specified when a generic associated types
+                        // are from higher-ranked trait bounds
+                        self.suggest_static_lifetime_for_gat_from_hrtb(
+                            &mut diag,
+                            type_test.lower_bound,
+                        );
+
+                        self.buffer_error(diag);
                     }
                 }
 
diff --git a/compiler/rustc_borrowck/src/lib.rs b/compiler/rustc_borrowck/src/lib.rs
index 2384f851a66..73ea7314b75 100644
--- a/compiler/rustc_borrowck/src/lib.rs
+++ b/compiler/rustc_borrowck/src/lib.rs
@@ -5,6 +5,7 @@
 #![feature(let_chains)]
 #![feature(min_specialization)]
 #![feature(never_type)]
+#![feature(once_cell)]
 #![feature(rustc_attrs)]
 #![feature(stmt_expr_attributes)]
 #![feature(trusted_step)]
@@ -39,6 +40,7 @@ use rustc_span::{Span, Symbol};
 
 use either::Either;
 use smallvec::SmallVec;
+use std::cell::OnceCell;
 use std::cell::RefCell;
 use std::collections::BTreeMap;
 use std::rc::Rc;
@@ -333,7 +335,7 @@ fn do_mir_borrowck<'tcx>(
                 used_mut: Default::default(),
                 used_mut_upvars: SmallVec::new(),
                 borrow_set: Rc::clone(&borrow_set),
-                dominators: Dominators::dummy(), // not used
+                dominators: Default::default(),
                 upvars: Vec::new(),
                 local_names: IndexVec::from_elem(None, &promoted_body.local_decls),
                 region_names: RefCell::default(),
@@ -346,8 +348,6 @@ fn do_mir_borrowck<'tcx>(
         };
     }
 
-    let dominators = body.basic_blocks.dominators();
-
     let mut mbcx = MirBorrowckCtxt {
         infcx,
         param_env,
@@ -364,7 +364,7 @@ fn do_mir_borrowck<'tcx>(
         used_mut: Default::default(),
         used_mut_upvars: SmallVec::new(),
         borrow_set: Rc::clone(&borrow_set),
-        dominators,
+        dominators: Default::default(),
         upvars,
         local_names,
         region_names: RefCell::default(),
@@ -534,7 +534,7 @@ struct MirBorrowckCtxt<'cx, 'tcx> {
     borrow_set: Rc<BorrowSet<'tcx>>,
 
     /// Dominators for MIR
-    dominators: Dominators<BasicBlock>,
+    dominators: OnceCell<Dominators<BasicBlock>>,
 
     /// Information about upvars not necessarily preserved in types or MIR
     upvars: Vec<Upvar<'tcx>>,
@@ -1051,7 +1051,7 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
 
                 (Read(kind), BorrowKind::Unique | BorrowKind::Mut { .. }) => {
                     // Reading from mere reservations of mutable-borrows is OK.
-                    if !is_active(&this.dominators, borrow, location) {
+                    if !is_active(this.dominators(), borrow, location) {
                         assert!(allow_two_phase_borrow(borrow.kind));
                         return Control::Continue;
                     }
@@ -2219,6 +2219,10 @@ impl<'cx, 'tcx> MirBorrowckCtxt<'cx, 'tcx> {
     fn is_upvar_field_projection(&self, place_ref: PlaceRef<'tcx>) -> Option<Field> {
         path_utils::is_upvar_field_projection(self.infcx.tcx, &self.upvars, place_ref, self.body())
     }
+
+    fn dominators(&self) -> &Dominators<BasicBlock> {
+        self.dominators.get_or_init(|| self.body.basic_blocks.dominators())
+    }
 }
 
 mod error {
diff --git a/compiler/rustc_borrowck/src/region_infer/mod.rs b/compiler/rustc_borrowck/src/region_infer/mod.rs
index 89788c16cbb..238172ea399 100644
--- a/compiler/rustc_borrowck/src/region_infer/mod.rs
+++ b/compiler/rustc_borrowck/src/region_infer/mod.rs
@@ -527,6 +527,14 @@ impl<'tcx> RegionInferenceContext<'tcx> {
         self.scc_values.region_value_str(scc)
     }
 
+    pub(crate) fn placeholders_contained_in<'a>(
+        &'a self,
+        r: RegionVid,
+    ) -> impl Iterator<Item = ty::PlaceholderRegion> + 'a {
+        let scc = self.constraint_sccs.scc(r.to_region_vid());
+        self.scc_values.placeholders_contained_in(scc)
+    }
+
     /// Returns access to the value of `r` for debugging purposes.
     pub(crate) fn region_universe(&self, r: RegionVid) -> ty::UniverseIndex {
         let scc = self.constraint_sccs.scc(r.to_region_vid());
diff --git a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
index c6e42336ef8..db5a67a8b44 100644
--- a/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
+++ b/compiler/rustc_borrowck/src/region_infer/opaque_types.rs
@@ -12,6 +12,8 @@ use rustc_span::Span;
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
 use rustc_trait_selection::traits::ObligationCtxt;
 
+use crate::session_diagnostics::NonGenericOpaqueTypeParam;
+
 use super::RegionInferenceContext;
 
 impl<'tcx> RegionInferenceContext<'tcx> {
@@ -250,7 +252,7 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
         }
 
         let definition_ty = instantiated_ty
-            .remap_generic_params_to_declaration_params(opaque_type_key, self.tcx, false, origin)
+            .remap_generic_params_to_declaration_params(opaque_type_key, self.tcx, false)
             .ty;
 
         if !check_opaque_type_parameter_valid(
@@ -389,17 +391,13 @@ fn check_opaque_type_parameter_valid(
         } else {
             // Prevent `fn foo() -> Foo<u32>` from being defining.
             let opaque_param = opaque_generics.param_at(i, tcx);
-            tcx.sess
-                .struct_span_err(span, "non-defining opaque type use in defining scope")
-                .span_note(
-                    tcx.def_span(opaque_param.def_id),
-                    &format!(
-                        "used non-generic {} `{}` for generic parameter",
-                        opaque_param.kind.descr(),
-                        arg,
-                    ),
-                )
-                .emit();
+            let kind = opaque_param.kind.descr();
+            tcx.sess.emit_err(NonGenericOpaqueTypeParam {
+                ty: arg,
+                kind,
+                span,
+                param_span: tcx.def_span(opaque_param.def_id),
+            });
             return false;
         }
     }
diff --git a/compiler/rustc_borrowck/src/session_diagnostics.rs b/compiler/rustc_borrowck/src/session_diagnostics.rs
index 577332c0744..23acf159240 100644
--- a/compiler/rustc_borrowck/src/session_diagnostics.rs
+++ b/compiler/rustc_borrowck/src/session_diagnostics.rs
@@ -1,6 +1,6 @@
 use rustc_errors::{IntoDiagnosticArg, MultiSpan};
 use rustc_macros::{Diagnostic, LintDiagnostic, Subdiagnostic};
-use rustc_middle::ty::Ty;
+use rustc_middle::ty::{GenericArg, Ty};
 use rustc_span::Span;
 
 use crate::diagnostics::RegionName;
@@ -240,3 +240,14 @@ pub(crate) struct MoveBorrow<'a> {
     #[label]
     pub borrow_span: Span,
 }
+
+#[derive(Diagnostic)]
+#[diag(borrowck_opaque_type_non_generic_param, code = "E0792")]
+pub(crate) struct NonGenericOpaqueTypeParam<'a, 'tcx> {
+    pub ty: GenericArg<'tcx>,
+    pub kind: &'a str,
+    #[primary_span]
+    pub span: Span,
+    #[label]
+    pub param_span: Span,
+}
diff --git a/compiler/rustc_borrowck/src/type_check/canonical.rs b/compiler/rustc_borrowck/src/type_check/canonical.rs
index 02222c0a03c..11729e2c83f 100644
--- a/compiler/rustc_borrowck/src/type_check/canonical.rs
+++ b/compiler/rustc_borrowck/src/type_check/canonical.rs
@@ -107,11 +107,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         instantiated_predicates: ty::InstantiatedPredicates<'tcx>,
         locations: Locations,
     ) {
-        for (predicate, span) in instantiated_predicates
-            .predicates
-            .into_iter()
-            .zip(instantiated_predicates.spans.into_iter())
-        {
+        for (predicate, span) in instantiated_predicates {
             debug!(?predicate);
             let category = ConstraintCategory::Predicate(span);
             let predicate = self.normalize_with_category(predicate, locations, category);
diff --git a/compiler/rustc_borrowck/src/type_check/free_region_relations.rs b/compiler/rustc_borrowck/src/type_check/free_region_relations.rs
index a1256008990..82ff862479e 100644
--- a/compiler/rustc_borrowck/src/type_check/free_region_relations.rs
+++ b/compiler/rustc_borrowck/src/type_check/free_region_relations.rs
@@ -359,14 +359,9 @@ impl<'tcx> UniversalRegionRelationsBuilder<'_, 'tcx> {
                         .insert(ty::OutlivesPredicate(GenericKind::Param(param_b), r_a));
                 }
 
-                OutlivesBound::RegionSubProjection(r_a, projection_b) => {
+                OutlivesBound::RegionSubAlias(r_a, alias_b) => {
                     self.region_bound_pairs
-                        .insert(ty::OutlivesPredicate(GenericKind::Projection(projection_b), r_a));
-                }
-
-                OutlivesBound::RegionSubOpaque(r_a, def_id, substs) => {
-                    self.region_bound_pairs
-                        .insert(ty::OutlivesPredicate(GenericKind::Opaque(def_id, substs), r_a));
+                        .insert(ty::OutlivesPredicate(GenericKind::Alias(alias_b), r_a));
                 }
             }
         }
diff --git a/compiler/rustc_builtin_macros/src/deriving/clone.rs b/compiler/rustc_builtin_macros/src/deriving/clone.rs
index 3f174e2d901..ef5a75f428d 100644
--- a/compiler/rustc_builtin_macros/src/deriving/clone.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/clone.rs
@@ -82,7 +82,7 @@ pub fn expand_deriving_clone(
             nonself_args: Vec::new(),
             ret_ty: Self_,
             attributes: attrs,
-            unify_fieldless_variants: false,
+            fieldless_variants_strategy: FieldlessVariantsStrategy::Default,
             combine_substructure: substructure,
         }],
         associated_types: Vec::new(),
@@ -177,7 +177,9 @@ fn cs_clone(
             all_fields = af;
             vdata = &variant.data;
         }
-        EnumTag(..) => cx.span_bug(trait_span, &format!("enum tags in `derive({})`", name,)),
+        EnumTag(..) | AllFieldlessEnum(..) => {
+            cx.span_bug(trait_span, &format!("enum tags in `derive({})`", name,))
+        }
         StaticEnum(..) | StaticStruct(..) => {
             cx.span_bug(trait_span, &format!("associated function in `derive({})`", name))
         }
diff --git a/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs b/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs
index f861d47ed40..3e994f037ad 100644
--- a/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/cmp/eq.rs
@@ -36,7 +36,7 @@ pub fn expand_deriving_eq(
             nonself_args: vec![],
             ret_ty: Unit,
             attributes: attrs,
-            unify_fieldless_variants: true,
+            fieldless_variants_strategy: FieldlessVariantsStrategy::Unify,
             combine_substructure: combine_substructure(Box::new(|a, b, c| {
                 cs_total_eq_assert(a, b, c)
             })),
diff --git a/compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs b/compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs
index 96d18c7afb9..a926fca4e65 100644
--- a/compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/cmp/ord.rs
@@ -29,7 +29,7 @@ pub fn expand_deriving_ord(
             nonself_args: vec![(self_ref(), sym::other)],
             ret_ty: Path(path_std!(cmp::Ordering)),
             attributes: attrs,
-            unify_fieldless_variants: true,
+            fieldless_variants_strategy: FieldlessVariantsStrategy::Unify,
             combine_substructure: combine_substructure(Box::new(|a, b, c| cs_cmp(a, b, c))),
         }],
         associated_types: Vec::new(),
diff --git a/compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs b/compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs
index 7f95551fc48..9051fe0b28a 100644
--- a/compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/cmp/partial_eq.rs
@@ -76,7 +76,7 @@ pub fn expand_deriving_partial_eq(
         nonself_args: vec![(self_ref(), sym::other)],
         ret_ty: Path(path_local!(bool)),
         attributes: attrs,
-        unify_fieldless_variants: true,
+        fieldless_variants_strategy: FieldlessVariantsStrategy::Unify,
         combine_substructure: combine_substructure(Box::new(|a, b, c| cs_eq(a, b, c))),
     }];
 
diff --git a/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs b/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs
index 5c4e5b7f816..c9dc8921262 100644
--- a/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/cmp/partial_ord.rs
@@ -28,7 +28,7 @@ pub fn expand_deriving_partial_ord(
         nonself_args: vec![(self_ref(), sym::other)],
         ret_ty,
         attributes: attrs,
-        unify_fieldless_variants: true,
+        fieldless_variants_strategy: FieldlessVariantsStrategy::Unify,
         combine_substructure: combine_substructure(Box::new(|cx, span, substr| {
             cs_partial_cmp(cx, span, substr)
         })),
diff --git a/compiler/rustc_builtin_macros/src/deriving/debug.rs b/compiler/rustc_builtin_macros/src/deriving/debug.rs
index 5b1b7e6804c..e0f487e8648 100644
--- a/compiler/rustc_builtin_macros/src/deriving/debug.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/debug.rs
@@ -2,6 +2,7 @@ use crate::deriving::generic::ty::*;
 use crate::deriving::generic::*;
 use crate::deriving::path_std;
 
+use ast::EnumDef;
 use rustc_ast::{self as ast, MetaItem};
 use rustc_expand::base::{Annotatable, ExtCtxt};
 use rustc_span::symbol::{sym, Ident, Symbol};
@@ -31,7 +32,8 @@ pub fn expand_deriving_debug(
             nonself_args: vec![(fmtr, sym::f)],
             ret_ty: Path(path_std!(fmt::Result)),
             attributes: ast::AttrVec::new(),
-            unify_fieldless_variants: false,
+            fieldless_variants_strategy:
+                FieldlessVariantsStrategy::SpecializeIfAllVariantsFieldless,
             combine_substructure: combine_substructure(Box::new(|a, b, c| {
                 show_substructure(a, b, c)
             })),
@@ -43,16 +45,18 @@ pub fn expand_deriving_debug(
 }
 
 fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>) -> BlockOrExpr {
+    // We want to make sure we have the ctxt set so that we can use unstable methods
+    let span = cx.with_def_site_ctxt(span);
+
     let (ident, vdata, fields) = match substr.fields {
         Struct(vdata, fields) => (substr.type_ident, *vdata, fields),
         EnumMatching(_, _, v, fields) => (v.ident, &v.data, fields),
+        AllFieldlessEnum(enum_def) => return show_fieldless_enum(cx, span, enum_def, substr),
         EnumTag(..) | StaticStruct(..) | StaticEnum(..) => {
             cx.span_bug(span, "nonsensical .fields in `#[derive(Debug)]`")
         }
     };
 
-    // We want to make sure we have the ctxt set so that we can use unstable methods
-    let span = cx.with_def_site_ctxt(span);
     let name = cx.expr_str(span, ident.name);
     let fmt = substr.nonselflike_args[0].clone();
 
@@ -173,3 +177,47 @@ fn show_substructure(cx: &mut ExtCtxt<'_>, span: Span, substr: &Substructure<'_>
         BlockOrExpr::new_mixed(stmts, Some(expr))
     }
 }
+
+/// Special case for enums with no fields. Builds:
+/// ```text
+/// impl ::core::fmt::Debug for A {
+///     fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
+///          ::core::fmt::Formatter::write_str(f,
+///             match self {
+///                 A::A => "A",
+///                 A::B() => "B",
+///                 A::C {} => "C",
+///             })
+///     }
+/// }
+/// ```
+fn show_fieldless_enum(
+    cx: &mut ExtCtxt<'_>,
+    span: Span,
+    def: &EnumDef,
+    substr: &Substructure<'_>,
+) -> BlockOrExpr {
+    let fmt = substr.nonselflike_args[0].clone();
+    let arms = def
+        .variants
+        .iter()
+        .map(|v| {
+            let variant_path = cx.path(span, vec![substr.type_ident, v.ident]);
+            let pat = match &v.data {
+                ast::VariantData::Tuple(fields, _) => {
+                    debug_assert!(fields.is_empty());
+                    cx.pat_tuple_struct(span, variant_path, vec![])
+                }
+                ast::VariantData::Struct(fields, _) => {
+                    debug_assert!(fields.is_empty());
+                    cx.pat_struct(span, variant_path, vec![])
+                }
+                ast::VariantData::Unit(_) => cx.pat_path(span, variant_path),
+            };
+            cx.arm(span, pat, cx.expr_str(span, v.ident.name))
+        })
+        .collect::<Vec<_>>();
+    let name = cx.expr_match(span, cx.expr_self(span), arms);
+    let fn_path_write_str = cx.std_path(&[sym::fmt, sym::Formatter, sym::write_str]);
+    BlockOrExpr::new_expr(cx.expr_call_global(span, fn_path_write_str, vec![fmt, name]))
+}
diff --git a/compiler/rustc_builtin_macros/src/deriving/decodable.rs b/compiler/rustc_builtin_macros/src/deriving/decodable.rs
index 62af02c2bb4..5f9519dad1b 100644
--- a/compiler/rustc_builtin_macros/src/deriving/decodable.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/decodable.rs
@@ -49,7 +49,7 @@ pub fn expand_deriving_rustc_decodable(
                 PathKind::Std,
             )),
             attributes: ast::AttrVec::new(),
-            unify_fieldless_variants: false,
+            fieldless_variants_strategy: FieldlessVariantsStrategy::Default,
             combine_substructure: combine_substructure(Box::new(|a, b, c| {
                 decodable_substructure(a, b, c, krate)
             })),
diff --git a/compiler/rustc_builtin_macros/src/deriving/default.rs b/compiler/rustc_builtin_macros/src/deriving/default.rs
index eb66c4a69a6..18270747296 100644
--- a/compiler/rustc_builtin_macros/src/deriving/default.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/default.rs
@@ -34,7 +34,7 @@ pub fn expand_deriving_default(
             nonself_args: Vec::new(),
             ret_ty: Self_,
             attributes: attrs,
-            unify_fieldless_variants: false,
+            fieldless_variants_strategy: FieldlessVariantsStrategy::Default,
             combine_substructure: combine_substructure(Box::new(|cx, trait_span, substr| {
                 match substr.fields {
                     StaticStruct(_, fields) => {
diff --git a/compiler/rustc_builtin_macros/src/deriving/encodable.rs b/compiler/rustc_builtin_macros/src/deriving/encodable.rs
index 68bc0ff2ec0..2afeed927ac 100644
--- a/compiler/rustc_builtin_macros/src/deriving/encodable.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/encodable.rs
@@ -133,7 +133,7 @@ pub fn expand_deriving_rustc_encodable(
                 PathKind::Std,
             )),
             attributes: AttrVec::new(),
-            unify_fieldless_variants: false,
+            fieldless_variants_strategy: FieldlessVariantsStrategy::Default,
             combine_substructure: combine_substructure(Box::new(|a, b, c| {
                 encodable_substructure(a, b, c, krate)
             })),
diff --git a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
index beac591bfc8..17b7ac0eba1 100644
--- a/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/generic/mod.rs
@@ -222,14 +222,27 @@ pub struct MethodDef<'a> {
 
     pub attributes: ast::AttrVec,
 
-    /// Can we combine fieldless variants for enums into a single match arm?
-    /// If true, indicates that the trait operation uses the enum tag in some
-    /// way.
-    pub unify_fieldless_variants: bool,
+    pub fieldless_variants_strategy: FieldlessVariantsStrategy,
 
     pub combine_substructure: RefCell<CombineSubstructureFunc<'a>>,
 }
 
+/// How to handle fieldless enum variants.
+#[derive(PartialEq)]
+pub enum FieldlessVariantsStrategy {
+    /// Combine fieldless variants into a single match arm.
+    /// This assumes that relevant information has been handled
+    /// by looking at the enum's discriminant.
+    Unify,
+    /// Don't do anything special about fieldless variants. They are
+    /// handled like any other variant.
+    Default,
+    /// If all variants of the enum are fieldless, expand the special
+    /// `AllFieldLessEnum` substructure, so that the entire enum can be handled
+    /// at once.
+    SpecializeIfAllVariantsFieldless,
+}
+
 /// All the data about the data structure/method being derived upon.
 pub struct Substructure<'a> {
     /// ident of self
@@ -264,9 +277,14 @@ pub enum StaticFields {
 
 /// A summary of the possible sets of fields.
 pub enum SubstructureFields<'a> {
-    /// A non-static method with `Self` is a struct.
+    /// A non-static method where `Self` is a struct.
     Struct(&'a ast::VariantData, Vec<FieldInfo>),
 
+    /// A non-static method handling the entire enum at once
+    /// (after it has been determined that none of the enum
+    /// variants has any fields).
+    AllFieldlessEnum(&'a ast::EnumDef),
+
     /// Matching variants of the enum: variant index, variant count, ast::Variant,
     /// fields: the field name is only non-`None` in the case of a struct
     /// variant.
@@ -1086,8 +1104,8 @@ impl<'a> MethodDef<'a> {
     /// ```
     /// Creates a tag check combined with a match for a tuple of all
     /// `selflike_args`, with an arm for each variant with fields, possibly an
-    /// arm for each fieldless variant (if `!unify_fieldless_variants` is not
-    /// true), and possibly a default arm.
+    /// arm for each fieldless variant (if `unify_fieldless_variants` is not
+    /// `Unify`), and possibly a default arm.
     fn expand_enum_method_body<'b>(
         &self,
         cx: &mut ExtCtxt<'_>,
@@ -1101,7 +1119,8 @@ impl<'a> MethodDef<'a> {
         let variants = &enum_def.variants;
 
         // Traits that unify fieldless variants always use the tag(s).
-        let uses_tags = self.unify_fieldless_variants;
+        let unify_fieldless_variants =
+            self.fieldless_variants_strategy == FieldlessVariantsStrategy::Unify;
 
         // There is no sensible code to be generated for *any* deriving on a
         // zero-variant enum. So we just generate a failing expression.
@@ -1161,23 +1180,35 @@ impl<'a> MethodDef<'a> {
         // match is necessary.
         let all_fieldless = variants.iter().all(|v| v.data.fields().is_empty());
         if all_fieldless {
-            if uses_tags && variants.len() > 1 {
-                // If the type is fieldless and the trait uses the tag and
-                // there are multiple variants, we need just an operation on
-                // the tag(s).
-                let (tag_field, mut tag_let_stmts) = get_tag_pieces(cx);
-                let mut tag_check = self.call_substructure_method(
-                    cx,
-                    trait_,
-                    type_ident,
-                    nonselflike_args,
-                    &EnumTag(tag_field, None),
-                );
-                tag_let_stmts.append(&mut tag_check.0);
-                return BlockOrExpr(tag_let_stmts, tag_check.1);
-            }
-
-            if variants.len() == 1 {
+            if variants.len() > 1 {
+                match self.fieldless_variants_strategy {
+                    FieldlessVariantsStrategy::Unify => {
+                        // If the type is fieldless and the trait uses the tag and
+                        // there are multiple variants, we need just an operation on
+                        // the tag(s).
+                        let (tag_field, mut tag_let_stmts) = get_tag_pieces(cx);
+                        let mut tag_check = self.call_substructure_method(
+                            cx,
+                            trait_,
+                            type_ident,
+                            nonselflike_args,
+                            &EnumTag(tag_field, None),
+                        );
+                        tag_let_stmts.append(&mut tag_check.0);
+                        return BlockOrExpr(tag_let_stmts, tag_check.1);
+                    }
+                    FieldlessVariantsStrategy::SpecializeIfAllVariantsFieldless => {
+                        return self.call_substructure_method(
+                            cx,
+                            trait_,
+                            type_ident,
+                            nonselflike_args,
+                            &AllFieldlessEnum(enum_def),
+                        );
+                    }
+                    FieldlessVariantsStrategy::Default => (),
+                }
+            } else if variants.len() == 1 {
                 // If there is a single variant, we don't need an operation on
                 // the tag(s). Just use the most degenerate result.
                 return self.call_substructure_method(
@@ -1187,7 +1218,7 @@ impl<'a> MethodDef<'a> {
                     nonselflike_args,
                     &EnumMatching(0, 1, &variants[0], Vec::new()),
                 );
-            };
+            }
         }
 
         // These arms are of the form:
@@ -1198,7 +1229,7 @@ impl<'a> MethodDef<'a> {
         let mut match_arms: Vec<ast::Arm> = variants
             .iter()
             .enumerate()
-            .filter(|&(_, v)| !(self.unify_fieldless_variants && v.data.fields().is_empty()))
+            .filter(|&(_, v)| !(unify_fieldless_variants && v.data.fields().is_empty()))
             .map(|(index, variant)| {
                 // A single arm has form (&VariantK, &VariantK, ...) => BodyK
                 // (see "Final wrinkle" note below for why.)
@@ -1249,7 +1280,7 @@ impl<'a> MethodDef<'a> {
         // Add a default arm to the match, if necessary.
         let first_fieldless = variants.iter().find(|v| v.data.fields().is_empty());
         let default = match first_fieldless {
-            Some(v) if self.unify_fieldless_variants => {
+            Some(v) if unify_fieldless_variants => {
                 // We need a default case that handles all the fieldless
                 // variants. The index and actual variant aren't meaningful in
                 // this case, so just use dummy values.
@@ -1296,7 +1327,7 @@ impl<'a> MethodDef<'a> {
         // If the trait uses the tag and there are multiple variants, we need
         // to add a tag check operation before the match. Otherwise, the match
         // is enough.
-        if uses_tags && variants.len() > 1 {
+        if unify_fieldless_variants && variants.len() > 1 {
             let (tag_field, mut tag_let_stmts) = get_tag_pieces(cx);
 
             // Combine a tag check with the match.
@@ -1580,5 +1611,6 @@ where
             }
         }
         StaticEnum(..) | StaticStruct(..) => cx.span_bug(trait_span, "static function in `derive`"),
+        AllFieldlessEnum(..) => cx.span_bug(trait_span, "fieldless enum in `derive`"),
     }
 }
diff --git a/compiler/rustc_builtin_macros/src/deriving/hash.rs b/compiler/rustc_builtin_macros/src/deriving/hash.rs
index c136bb7141a..f8570d8f86a 100644
--- a/compiler/rustc_builtin_macros/src/deriving/hash.rs
+++ b/compiler/rustc_builtin_macros/src/deriving/hash.rs
@@ -33,7 +33,7 @@ pub fn expand_deriving_hash(
             nonself_args: vec![(Ref(Box::new(Path(arg)), Mutability::Mut), sym::state)],
             ret_ty: Unit,
             attributes: AttrVec::new(),
-            unify_fieldless_variants: true,
+            fieldless_variants_strategy: FieldlessVariantsStrategy::Unify,
             combine_substructure: combine_substructure(Box::new(|a, b, c| {
                 hash_substructure(a, b, c)
             })),
diff --git a/compiler/rustc_codegen_cranelift/src/debuginfo/mod.rs b/compiler/rustc_codegen_cranelift/src/debuginfo/mod.rs
index 2ba012a77b0..28fbcb15b2b 100644
--- a/compiler/rustc_codegen_cranelift/src/debuginfo/mod.rs
+++ b/compiler/rustc_codegen_cranelift/src/debuginfo/mod.rs
@@ -68,7 +68,7 @@ impl DebugContext {
             .working_dir
             .to_string_lossy(FileNameDisplayPreference::Remapped)
             .into_owned();
-        let (name, file_info) = match tcx.sess.local_crate_source_file.clone() {
+        let (name, file_info) = match tcx.sess.local_crate_source_file() {
             Some(path) => {
                 let name = path.to_string_lossy().into_owned();
                 (name, None)
diff --git a/compiler/rustc_codegen_llvm/src/builder.rs b/compiler/rustc_codegen_llvm/src/builder.rs
index 5bf45a81e43..5e98deae48a 100644
--- a/compiler/rustc_codegen_llvm/src/builder.rs
+++ b/compiler/rustc_codegen_llvm/src/builder.rs
@@ -501,7 +501,7 @@ impl<'a, 'll, 'tcx> BuilderMethods<'a, 'tcx> for Builder<'a, 'll, 'tcx> {
             layout: TyAndLayout<'tcx>,
             offset: Size,
         ) {
-            if !scalar.is_always_valid(bx) {
+            if !scalar.is_uninit_valid() {
                 bx.noundef_metadata(load);
             }
 
diff --git a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
index 393bf30e9f8..22c61248b7d 100644
--- a/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
+++ b/compiler/rustc_codegen_llvm/src/coverageinfo/mapgen.rs
@@ -8,7 +8,7 @@ use rustc_codegen_ssa::coverageinfo::map::{Counter, CounterExpression};
 use rustc_codegen_ssa::traits::{ConstMethods, CoverageInfoMethods};
 use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir::def::DefKind;
-use rustc_hir::def_id::DefIdSet;
+use rustc_hir::def_id::DefId;
 use rustc_llvm::RustString;
 use rustc_middle::bug;
 use rustc_middle::middle::codegen_fn_attrs::CodegenFnAttrFlags;
@@ -291,7 +291,7 @@ fn add_unused_functions(cx: &CodegenCx<'_, '_>) {
 
     let ignore_unused_generics = tcx.sess.instrument_coverage_except_unused_generics();
 
-    let eligible_def_ids: DefIdSet = tcx
+    let eligible_def_ids: Vec<DefId> = tcx
         .mir_keys(())
         .iter()
         .filter_map(|local_def_id| {
@@ -317,7 +317,9 @@ fn add_unused_functions(cx: &CodegenCx<'_, '_>) {
 
     let codegenned_def_ids = tcx.codegened_and_inlined_items(());
 
-    for &non_codegenned_def_id in eligible_def_ids.difference(codegenned_def_ids) {
+    for non_codegenned_def_id in
+        eligible_def_ids.into_iter().filter(|id| !codegenned_def_ids.contains(id))
+    {
         let codegen_fn_attrs = tcx.codegen_fn_attrs(non_codegenned_def_id);
 
         // If a function is marked `#[no_coverage]`, then skip generating a
diff --git a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
index 48e3a812e4f..b6eb5ee183f 100644
--- a/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
+++ b/compiler/rustc_codegen_llvm/src/debuginfo/metadata.rs
@@ -782,10 +782,10 @@ pub fn build_compile_unit_di_node<'ll, 'tcx>(
     codegen_unit_name: &str,
     debug_context: &CodegenUnitDebugContext<'ll, 'tcx>,
 ) -> &'ll DIDescriptor {
-    let mut name_in_debuginfo = match tcx.sess.local_crate_source_file {
-        Some(ref path) => path.clone(),
-        None => PathBuf::from(tcx.crate_name(LOCAL_CRATE).as_str()),
-    };
+    let mut name_in_debuginfo = tcx
+        .sess
+        .local_crate_source_file()
+        .unwrap_or_else(|| PathBuf::from(tcx.crate_name(LOCAL_CRATE).as_str()));
 
     // To avoid breaking split DWARF, we need to ensure that each codegen unit
     // has a unique `DW_AT_name`. This is because there's a remote chance that
diff --git a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
index 8cb7d74b90d..57a99e74c21 100644
--- a/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
+++ b/compiler/rustc_codegen_ssa/src/back/symbol_export.rs
@@ -173,11 +173,15 @@ fn exported_symbols_provider_local(
         return &[];
     }
 
-    let mut symbols: Vec<_> = tcx
-        .reachable_non_generics(LOCAL_CRATE)
-        .iter()
-        .map(|(&def_id, &info)| (ExportedSymbol::NonGeneric(def_id), info))
-        .collect();
+    // FIXME: Sorting this is unnecessary since we are sorting later anyway.
+    //        Can we skip the later sorting?
+    let mut symbols: Vec<_> = tcx.with_stable_hashing_context(|hcx| {
+        tcx.reachable_non_generics(LOCAL_CRATE)
+            .to_sorted(&hcx, true)
+            .into_iter()
+            .map(|(&def_id, &info)| (ExportedSymbol::NonGeneric(def_id), info))
+            .collect()
+    });
 
     if tcx.entry_fn(()).is_some() {
         let exported_symbol =
diff --git a/compiler/rustc_codegen_ssa/src/base.rs b/compiler/rustc_codegen_ssa/src/base.rs
index f7312f6fcda..32d3cfe6fc6 100644
--- a/compiler/rustc_codegen_ssa/src/base.rs
+++ b/compiler/rustc_codegen_ssa/src/base.rs
@@ -964,16 +964,19 @@ pub fn provide(providers: &mut Providers) {
         };
 
         let (defids, _) = tcx.collect_and_partition_mono_items(cratenum);
-        for id in &*defids {
+
+        let any_for_speed = defids.items().any(|id| {
             let CodegenFnAttrs { optimize, .. } = tcx.codegen_fn_attrs(*id);
             match optimize {
-                attr::OptimizeAttr::None => continue,
-                attr::OptimizeAttr::Size => continue,
-                attr::OptimizeAttr::Speed => {
-                    return for_speed;
-                }
+                attr::OptimizeAttr::None | attr::OptimizeAttr::Size => false,
+                attr::OptimizeAttr::Speed => true,
             }
+        });
+
+        if any_for_speed {
+            return for_speed;
         }
+
         tcx.sess.opts.optimize
     };
 }
diff --git a/compiler/rustc_const_eval/src/const_eval/error.rs b/compiler/rustc_const_eval/src/const_eval/error.rs
index 13472cc2bfa..0579f781535 100644
--- a/compiler/rustc_const_eval/src/const_eval/error.rs
+++ b/compiler/rustc_const_eval/src/const_eval/error.rs
@@ -36,16 +36,16 @@ impl<'tcx> Into<InterpErrorInfo<'tcx>> for ConstEvalErrKind {
 impl fmt::Display for ConstEvalErrKind {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         use self::ConstEvalErrKind::*;
-        match *self {
+        match self {
             ConstAccessesStatic => write!(f, "constant accesses static"),
             ModifiedGlobal => {
                 write!(f, "modifying a static's initial value from another static's initializer")
             }
-            AssertFailure(ref msg) => write!(f, "{:?}", msg),
+            AssertFailure(msg) => write!(f, "{:?}", msg),
             Panic { msg, line, col, file } => {
                 write!(f, "the evaluated program panicked at '{}', {}:{}:{}", msg, file, line, col)
             }
-            Abort(ref msg) => write!(f, "{}", msg),
+            Abort(msg) => write!(f, "{}", msg),
         }
     }
 }
diff --git a/compiler/rustc_const_eval/src/const_eval/machine.rs b/compiler/rustc_const_eval/src/const_eval/machine.rs
index 4f7c1fc96f1..4709514c82e 100644
--- a/compiler/rustc_const_eval/src/const_eval/machine.rs
+++ b/compiler/rustc_const_eval/src/const_eval/machine.rs
@@ -225,7 +225,7 @@ impl<'mir, 'tcx: 'mir> CompileTimeEvalContext<'mir, 'tcx> {
     /// `align_offset(ptr, target_align)` needs special handling in const eval, because the pointer
     /// may not have an address.
     ///
-    /// If `ptr` does have a known address, then we return `CONTINUE` and the function call should
+    /// If `ptr` does have a known address, then we return `Continue(())` and the function call should
     /// proceed as normal.
     ///
     /// If `ptr` doesn't have an address, but its underlying allocation's alignment is at most
@@ -273,18 +273,18 @@ impl<'mir, 'tcx: 'mir> CompileTimeEvalContext<'mir, 'tcx> {
                         ret,
                         StackPopUnwind::NotAllowed,
                     )?;
-                    Ok(ControlFlow::BREAK)
+                    Ok(ControlFlow::Break(()))
                 } else {
                     // Not alignable in const, return `usize::MAX`.
                     let usize_max = Scalar::from_machine_usize(self.machine_usize_max(), self);
                     self.write_scalar(usize_max, dest)?;
                     self.return_to_block(ret)?;
-                    Ok(ControlFlow::BREAK)
+                    Ok(ControlFlow::Break(()))
                 }
             }
             Err(_addr) => {
                 // The pointer has an address, continue with function call.
-                Ok(ControlFlow::CONTINUE)
+                Ok(ControlFlow::Continue(()))
             }
         }
     }
@@ -533,7 +533,7 @@ impl<'mir, 'tcx> interpret::Machine<'mir, 'tcx> for CompileTimeInterpreter<'mir,
         let eval_to_int =
             |op| ecx.read_immediate(&ecx.eval_operand(op, None)?).map(|x| x.to_const_int());
         let err = match msg {
-            BoundsCheck { ref len, ref index } => {
+            BoundsCheck { len, index } => {
                 let len = eval_to_int(len)?;
                 let index = eval_to_int(index)?;
                 BoundsCheck { len, index }
diff --git a/compiler/rustc_const_eval/src/interpret/cast.rs b/compiler/rustc_const_eval/src/interpret/cast.rs
index 986b6d65530..b2c847d3fd8 100644
--- a/compiler/rustc_const_eval/src/interpret/cast.rs
+++ b/compiler/rustc_const_eval/src/interpret/cast.rs
@@ -347,7 +347,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 let new_vptr = self.get_vtable_ptr(ty, data_b.principal())?;
                 self.write_immediate(Immediate::new_dyn_trait(old_data, new_vptr, self), dest)
             }
-            (_, &ty::Dynamic(ref data, _, ty::Dyn)) => {
+            (_, &ty::Dynamic(data, _, ty::Dyn)) => {
                 // Initial cast from sized to dyn trait
                 let vtable = self.get_vtable_ptr(src_pointee_ty, data.principal())?;
                 let ptr = self.read_scalar(src)?;
diff --git a/compiler/rustc_const_eval/src/interpret/intrinsics.rs b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
index 666fcbd6f80..cc7b6c91b60 100644
--- a/compiler/rustc_const_eval/src/interpret/intrinsics.rs
+++ b/compiler/rustc_const_eval/src/interpret/intrinsics.rs
@@ -79,9 +79,7 @@ pub(crate) fn eval_nullary_intrinsic<'tcx>(
         }
         sym::variant_count => match tp_ty.kind() {
             // Correctly handles non-monomorphic calls, so there is no need for ensure_monomorphic_enough.
-            ty::Adt(ref adt, _) => {
-                ConstValue::from_machine_usize(adt.variants().len() as u64, &tcx)
-            }
+            ty::Adt(adt, _) => ConstValue::from_machine_usize(adt.variants().len() as u64, &tcx),
             ty::Alias(..) | ty::Param(_) | ty::Placeholder(_) | ty::Infer(_) => {
                 throw_inval!(TooGeneric)
             }
diff --git a/compiler/rustc_const_eval/src/interpret/memory.rs b/compiler/rustc_const_eval/src/interpret/memory.rs
index 2f31bfc9100..291bfb2b558 100644
--- a/compiler/rustc_const_eval/src/interpret/memory.rs
+++ b/compiler/rustc_const_eval/src/interpret/memory.rs
@@ -863,7 +863,7 @@ impl<'a, 'mir, 'tcx, M: Machine<'mir, 'tcx>> std::fmt::Debug for DumpAllocs<'a,
 
             write!(fmt, "{id:?}")?;
             match self.ecx.memory.alloc_map.get(id) {
-                Some(&(kind, ref alloc)) => {
+                Some((kind, alloc)) => {
                     // normal alloc
                     write!(fmt, " ({}, ", kind)?;
                     write_allocation_track_relocs(
diff --git a/compiler/rustc_const_eval/src/interpret/operand.rs b/compiler/rustc_const_eval/src/interpret/operand.rs
index 7e93f1b8ef5..befc0928f3d 100644
--- a/compiler/rustc_const_eval/src/interpret/operand.rs
+++ b/compiler/rustc_const_eval/src/interpret/operand.rs
@@ -533,11 +533,11 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
         layout: Option<TyAndLayout<'tcx>>,
     ) -> InterpResult<'tcx, OpTy<'tcx, M::Provenance>> {
         use rustc_middle::mir::Operand::*;
-        let op = match *mir_op {
+        let op = match mir_op {
             // FIXME: do some more logic on `move` to invalidate the old location
-            Copy(place) | Move(place) => self.eval_place_to_op(place, layout)?,
+            &Copy(place) | &Move(place) => self.eval_place_to_op(place, layout)?,
 
-            Constant(ref constant) => {
+            Constant(constant) => {
                 let c =
                     self.subst_from_current_frame_and_normalize_erasing_regions(constant.literal)?;
 
diff --git a/compiler/rustc_const_eval/src/interpret/step.rs b/compiler/rustc_const_eval/src/interpret/step.rs
index 81b44a49484..fad4cb06cd6 100644
--- a/compiler/rustc_const_eval/src/interpret/step.rs
+++ b/compiler/rustc_const_eval/src/interpret/step.rs
@@ -111,7 +111,7 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 M::retag_place_contents(self, *kind, &dest)?;
             }
 
-            Intrinsic(box ref intrinsic) => self.emulate_nondiverging_intrinsic(intrinsic)?,
+            Intrinsic(box intrinsic) => self.emulate_nondiverging_intrinsic(intrinsic)?,
 
             // Statements we do not track.
             AscribeUserType(..) => {}
@@ -163,8 +163,8 @@ impl<'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> InterpCx<'mir, 'tcx, M> {
                 self.copy_op(&op, &dest, /*allow_transmute*/ false)?;
             }
 
-            CopyForDeref(ref place) => {
-                let op = self.eval_place_to_op(*place, Some(dest.layout))?;
+            CopyForDeref(place) => {
+                let op = self.eval_place_to_op(place, Some(dest.layout))?;
                 self.copy_op(&op, &dest, /* allow_transmute*/ false)?;
             }
 
diff --git a/compiler/rustc_const_eval/src/interpret/util.rs b/compiler/rustc_const_eval/src/interpret/util.rs
index a61d3ab40a5..cabc65e2c07 100644
--- a/compiler/rustc_const_eval/src/interpret/util.rs
+++ b/compiler/rustc_const_eval/src/interpret/util.rs
@@ -26,7 +26,7 @@ where
 
         fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
             if !ty.needs_subst() {
-                return ControlFlow::CONTINUE;
+                return ControlFlow::Continue(());
             }
 
             match *ty.kind() {
@@ -48,7 +48,7 @@ where
                             return subst.visit_with(self);
                         }
                     }
-                    ControlFlow::CONTINUE
+                    ControlFlow::Continue(())
                 }
                 _ => ty.super_visit_with(self),
             }
diff --git a/compiler/rustc_const_eval/src/interpret/validity.rs b/compiler/rustc_const_eval/src/interpret/validity.rs
index 43bea23b651..19e359986a1 100644
--- a/compiler/rustc_const_eval/src/interpret/validity.rs
+++ b/compiler/rustc_const_eval/src/interpret/validity.rs
@@ -419,7 +419,7 @@ impl<'rt, 'mir, 'tcx: 'mir, M: Machine<'mir, 'tcx>> ValidityVisitor<'rt, 'mir, '
             )
         }
         // Recursive checking
-        if let Some(ref mut ref_tracking) = self.ref_tracking {
+        if let Some(ref_tracking) = self.ref_tracking.as_deref_mut() {
             // Proceed recursively even for ZST, no reason to skip them!
             // `!` is a ZST and we want to validate it.
             if let Ok((alloc_id, _offset, _prov)) = self.ecx.ptr_try_get_alloc_id(place.ptr) {
diff --git a/compiler/rustc_const_eval/src/interpret/visitor.rs b/compiler/rustc_const_eval/src/interpret/visitor.rs
index 1a10851a9f9..f9efc2418db 100644
--- a/compiler/rustc_const_eval/src/interpret/visitor.rs
+++ b/compiler/rustc_const_eval/src/interpret/visitor.rs
@@ -481,12 +481,12 @@ macro_rules! make_value_visitor {
                 };
 
                 // Visit the fields of this value.
-                match v.layout().fields {
+                match &v.layout().fields {
                     FieldsShape::Primitive => {}
-                    FieldsShape::Union(fields) => {
+                    &FieldsShape::Union(fields) => {
                         self.visit_union(v, fields)?;
                     }
-                    FieldsShape::Arbitrary { ref offsets, .. } => {
+                    FieldsShape::Arbitrary { offsets, .. } => {
                         // FIXME: We collect in a vec because otherwise there are lifetime
                         // errors: Projecting to a field needs access to `ecx`.
                         let fields: Vec<InterpResult<'tcx, Self::V>> =
diff --git a/compiler/rustc_const_eval/src/lib.rs b/compiler/rustc_const_eval/src/lib.rs
index 46e7b09a55e..57b91df2d07 100644
--- a/compiler/rustc_const_eval/src/lib.rs
+++ b/compiler/rustc_const_eval/src/lib.rs
@@ -6,7 +6,6 @@ Rust MIR: a lowered representation of Rust.
 
 #![feature(assert_matches)]
 #![feature(box_patterns)]
-#![feature(control_flow_enum)]
 #![feature(decl_macro)]
 #![feature(exact_size_is_empty)]
 #![feature(let_chains)]
diff --git a/compiler/rustc_const_eval/src/transform/check_consts/check.rs b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
index d4c75cd55ce..79f1737e32b 100644
--- a/compiler/rustc_const_eval/src/transform/check_consts/check.rs
+++ b/compiler/rustc_const_eval/src/transform/check_consts/check.rs
@@ -442,7 +442,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
 
         self.super_rvalue(rvalue, location);
 
-        match *rvalue {
+        match rvalue {
             Rvalue::ThreadLocalRef(_) => self.check_op(ops::ThreadLocalAccess),
 
             Rvalue::Use(_)
@@ -451,18 +451,15 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
             | Rvalue::Discriminant(..)
             | Rvalue::Len(_) => {}
 
-            Rvalue::Aggregate(ref kind, ..) => {
-                if let AggregateKind::Generator(def_id, ..) = kind.as_ref() {
-                    if let Some(generator_kind) = self.tcx.generator_kind(def_id.to_def_id()) {
-                        if matches!(generator_kind, hir::GeneratorKind::Async(..)) {
-                            self.check_op(ops::Generator(generator_kind));
-                        }
-                    }
+            Rvalue::Aggregate(kind, ..) => {
+                if let AggregateKind::Generator(def_id, ..) = kind.as_ref()
+                    && let Some(generator_kind @ hir::GeneratorKind::Async(..)) = self.tcx.generator_kind(def_id.to_def_id())
+                {
+                    self.check_op(ops::Generator(generator_kind));
                 }
             }
 
-            Rvalue::Ref(_, kind @ BorrowKind::Mut { .. }, ref place)
-            | Rvalue::Ref(_, kind @ BorrowKind::Unique, ref place) => {
+            Rvalue::Ref(_, kind @ (BorrowKind::Mut { .. } | BorrowKind::Unique), place) => {
                 let ty = place.ty(self.body, self.tcx).ty;
                 let is_allowed = match ty.kind() {
                     // Inside a `static mut`, `&mut [...]` is allowed.
@@ -491,12 +488,12 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                 }
             }
 
-            Rvalue::AddressOf(Mutability::Mut, ref place) => {
+            Rvalue::AddressOf(Mutability::Mut, place) => {
                 self.check_mut_borrow(place.local, hir::BorrowKind::Raw)
             }
 
-            Rvalue::Ref(_, BorrowKind::Shared | BorrowKind::Shallow, ref place)
-            | Rvalue::AddressOf(Mutability::Not, ref place) => {
+            Rvalue::Ref(_, BorrowKind::Shared | BorrowKind::Shallow, place)
+            | Rvalue::AddressOf(Mutability::Not, place) => {
                 let borrowed_place_has_mut_interior = qualifs::in_place::<HasMutInterior, _>(
                     &self.ccx,
                     &mut |local| self.qualifs.has_mut_interior(self.ccx, local, location),
@@ -564,7 +561,7 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
             Rvalue::NullaryOp(NullOp::SizeOf | NullOp::AlignOf, _) => {}
             Rvalue::ShallowInitBox(_, _) => {}
 
-            Rvalue::UnaryOp(_, ref operand) => {
+            Rvalue::UnaryOp(_, operand) => {
                 let ty = operand.ty(self.body, self.tcx);
                 if is_int_bool_or_char(ty) {
                     // Int, bool, and char operations are fine.
@@ -575,8 +572,8 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                 }
             }
 
-            Rvalue::BinaryOp(op, box (ref lhs, ref rhs))
-            | Rvalue::CheckedBinaryOp(op, box (ref lhs, ref rhs)) => {
+            Rvalue::BinaryOp(op, box (lhs, rhs))
+            | Rvalue::CheckedBinaryOp(op, box (lhs, rhs)) => {
                 let lhs_ty = lhs.ty(self.body, self.tcx);
                 let rhs_ty = rhs.ty(self.body, self.tcx);
 
@@ -585,13 +582,16 @@ impl<'tcx> Visitor<'tcx> for Checker<'_, 'tcx> {
                 } else if lhs_ty.is_fn_ptr() || lhs_ty.is_unsafe_ptr() {
                     assert_eq!(lhs_ty, rhs_ty);
                     assert!(
-                        op == BinOp::Eq
-                            || op == BinOp::Ne
-                            || op == BinOp::Le
-                            || op == BinOp::Lt
-                            || op == BinOp::Ge
-                            || op == BinOp::Gt
-                            || op == BinOp::Offset
+                        matches!(
+                            op,
+                            BinOp::Eq
+                            | BinOp::Ne
+                            | BinOp::Le
+                            | BinOp::Lt
+                            | BinOp::Ge
+                            | BinOp::Gt
+                            | BinOp::Offset
+                        )
                     );
 
                     self.check_op(ops::RawPtrComparison);
diff --git a/compiler/rustc_const_eval/src/transform/promote_consts.rs b/compiler/rustc_const_eval/src/transform/promote_consts.rs
index 04ce701452b..fae6117f8f0 100644
--- a/compiler/rustc_const_eval/src/transform/promote_consts.rs
+++ b/compiler/rustc_const_eval/src/transform/promote_consts.rs
@@ -133,7 +133,7 @@ impl<'tcx> Visitor<'tcx> for Collector<'_, 'tcx> {
                 }
                 _ => { /* mark as unpromotable below */ }
             }
-        } else if let TempState::Defined { ref mut uses, .. } = *temp {
+        } else if let TempState::Defined { uses, .. } = temp {
             // We always allow borrows, even mutable ones, as we need
             // to promote mutable borrows of some ZSTs e.g., `&mut []`.
             let allowed_use = match context {
@@ -748,7 +748,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
         if loc.statement_index < num_stmts {
             let (mut rvalue, source_info) = {
                 let statement = &mut self.source[loc.block].statements[loc.statement_index];
-                let StatementKind::Assign(box (_, ref mut rhs)) = statement.kind else {
+                let StatementKind::Assign(box (_, rhs)) = &mut statement.kind else {
                     span_bug!(
                         statement.source_info.span,
                         "{:?} is not an assignment",
@@ -778,9 +778,9 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                 self.source[loc.block].terminator().clone()
             } else {
                 let terminator = self.source[loc.block].terminator_mut();
-                let target = match terminator.kind {
-                    TerminatorKind::Call { target: Some(target), .. } => target,
-                    ref kind => {
+                let target = match &terminator.kind {
+                    TerminatorKind::Call { target: Some(target), .. } => *target,
+                    kind => {
                         span_bug!(terminator.source_info.span, "{:?} not promotable", kind);
                     }
                 };
@@ -814,7 +814,7 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
                         ..terminator
                     };
                 }
-                ref kind => {
+                kind => {
                     span_bug!(terminator.source_info.span, "{:?} not promotable", kind);
                 }
             };
@@ -847,54 +847,50 @@ impl<'a, 'tcx> Promoter<'a, 'tcx> {
             let local_decls = &mut self.source.local_decls;
             let loc = candidate.location;
             let statement = &mut blocks[loc.block].statements[loc.statement_index];
-            match statement.kind {
-                StatementKind::Assign(box (
-                    _,
-                    Rvalue::Ref(ref mut region, borrow_kind, ref mut place),
-                )) => {
-                    // Use the underlying local for this (necessarily interior) borrow.
-                    let ty = local_decls[place.local].ty;
-                    let span = statement.source_info.span;
-
-                    let ref_ty = tcx.mk_ref(
-                        tcx.lifetimes.re_erased,
-                        ty::TypeAndMut { ty, mutbl: borrow_kind.to_mutbl_lossy() },
-                    );
+            let StatementKind::Assign(box (_, Rvalue::Ref(region, borrow_kind, place))) = &mut statement.kind else {
+                bug!()
+            };
 
-                    *region = tcx.lifetimes.re_erased;
-
-                    let mut projection = vec![PlaceElem::Deref];
-                    projection.extend(place.projection);
-                    place.projection = tcx.intern_place_elems(&projection);
-
-                    // Create a temp to hold the promoted reference.
-                    // This is because `*r` requires `r` to be a local,
-                    // otherwise we would use the `promoted` directly.
-                    let mut promoted_ref = LocalDecl::new(ref_ty, span);
-                    promoted_ref.source_info = statement.source_info;
-                    let promoted_ref = local_decls.push(promoted_ref);
-                    assert_eq!(self.temps.push(TempState::Unpromotable), promoted_ref);
-
-                    let promoted_ref_statement = Statement {
-                        source_info: statement.source_info,
-                        kind: StatementKind::Assign(Box::new((
-                            Place::from(promoted_ref),
-                            Rvalue::Use(promoted_operand(ref_ty, span)),
-                        ))),
-                    };
-                    self.extra_statements.push((loc, promoted_ref_statement));
-
-                    Rvalue::Ref(
-                        tcx.lifetimes.re_erased,
-                        borrow_kind,
-                        Place {
-                            local: mem::replace(&mut place.local, promoted_ref),
-                            projection: List::empty(),
-                        },
-                    )
-                }
-                _ => bug!(),
-            }
+            // Use the underlying local for this (necessarily interior) borrow.
+            let ty = local_decls[place.local].ty;
+            let span = statement.source_info.span;
+
+            let ref_ty = tcx.mk_ref(
+                tcx.lifetimes.re_erased,
+                ty::TypeAndMut { ty, mutbl: borrow_kind.to_mutbl_lossy() },
+            );
+
+            *region = tcx.lifetimes.re_erased;
+
+            let mut projection = vec![PlaceElem::Deref];
+            projection.extend(place.projection);
+            place.projection = tcx.intern_place_elems(&projection);
+
+            // Create a temp to hold the promoted reference.
+            // This is because `*r` requires `r` to be a local,
+            // otherwise we would use the `promoted` directly.
+            let mut promoted_ref = LocalDecl::new(ref_ty, span);
+            promoted_ref.source_info = statement.source_info;
+            let promoted_ref = local_decls.push(promoted_ref);
+            assert_eq!(self.temps.push(TempState::Unpromotable), promoted_ref);
+
+            let promoted_ref_statement = Statement {
+                source_info: statement.source_info,
+                kind: StatementKind::Assign(Box::new((
+                    Place::from(promoted_ref),
+                    Rvalue::Use(promoted_operand(ref_ty, span)),
+                ))),
+            };
+            self.extra_statements.push((loc, promoted_ref_statement));
+
+            Rvalue::Ref(
+                tcx.lifetimes.re_erased,
+                *borrow_kind,
+                Place {
+                    local: mem::replace(&mut place.local, promoted_ref),
+                    projection: List::empty(),
+                },
+            )
         };
 
         assert_eq!(self.new_block(), START_BLOCK);
diff --git a/compiler/rustc_const_eval/src/transform/validate.rs b/compiler/rustc_const_eval/src/transform/validate.rs
index 94e1b95a0eb..dd168a9ac3c 100644
--- a/compiler/rustc_const_eval/src/transform/validate.rs
+++ b/compiler/rustc_const_eval/src/transform/validate.rs
@@ -1,7 +1,8 @@
 //! Validates the MIR to ensure that invariants are upheld.
 
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_index::bit_set::BitSet;
+use rustc_index::vec::IndexVec;
 use rustc_infer::traits::Reveal;
 use rustc_middle::mir::interpret::Scalar;
 use rustc_middle::mir::visit::NonUseContext::VarDebugInfo;
@@ -18,7 +19,7 @@ use rustc_mir_dataflow::storage::always_storage_live_locals;
 use rustc_mir_dataflow::{Analysis, ResultsCursor};
 use rustc_target::abi::{Size, VariantIdx};
 
-#[derive(Copy, Clone, Debug)]
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
 enum EdgeKind {
     Unwind,
     Normal,
@@ -57,18 +58,20 @@ impl<'tcx> MirPass<'tcx> for Validator {
             .iterate_to_fixpoint()
             .into_results_cursor(body);
 
-        TypeChecker {
+        let mut checker = TypeChecker {
             when: &self.when,
             body,
             tcx,
             param_env,
             mir_phase,
+            unwind_edge_count: 0,
             reachable_blocks: traversal::reachable_as_bitset(body),
             storage_liveness,
             place_cache: Vec::new(),
             value_cache: Vec::new(),
-        }
-        .visit_body(body);
+        };
+        checker.visit_body(body);
+        checker.check_cleanup_control_flow();
     }
 }
 
@@ -78,6 +81,7 @@ struct TypeChecker<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     param_env: ParamEnv<'tcx>,
     mir_phase: MirPhase,
+    unwind_edge_count: usize,
     reachable_blocks: BitSet<BasicBlock>,
     storage_liveness: ResultsCursor<'a, 'tcx, MaybeStorageLive<'static>>,
     place_cache: Vec<PlaceRef<'tcx>>,
@@ -102,7 +106,7 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         );
     }
 
-    fn check_edge(&self, location: Location, bb: BasicBlock, edge_kind: EdgeKind) {
+    fn check_edge(&mut self, location: Location, bb: BasicBlock, edge_kind: EdgeKind) {
         if bb == START_BLOCK {
             self.fail(location, "start block must not have predecessors")
         }
@@ -111,10 +115,12 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
             match (src.is_cleanup, bb.is_cleanup, edge_kind) {
                 // Non-cleanup blocks can jump to non-cleanup blocks along non-unwind edges
                 (false, false, EdgeKind::Normal)
-                // Non-cleanup blocks can jump to cleanup blocks along unwind edges
-                | (false, true, EdgeKind::Unwind)
                 // Cleanup blocks can jump to cleanup blocks along non-unwind edges
                 | (true, true, EdgeKind::Normal) => {}
+                // Non-cleanup blocks can jump to cleanup blocks along unwind edges
+                (false, true, EdgeKind::Unwind) => {
+                    self.unwind_edge_count += 1;
+                }
                 // All other jumps are invalid
                 _ => {
                     self.fail(
@@ -134,6 +140,88 @@ impl<'a, 'tcx> TypeChecker<'a, 'tcx> {
         }
     }
 
+    fn check_cleanup_control_flow(&self) {
+        if self.unwind_edge_count <= 1 {
+            return;
+        }
+        let doms = self.body.basic_blocks.dominators();
+        let mut post_contract_node = FxHashMap::default();
+        // Reusing the allocation across invocations of the closure
+        let mut dom_path = vec![];
+        let mut get_post_contract_node = |mut bb| {
+            let root = loop {
+                if let Some(root) = post_contract_node.get(&bb) {
+                    break *root;
+                }
+                let parent = doms.immediate_dominator(bb);
+                dom_path.push(bb);
+                if !self.body.basic_blocks[parent].is_cleanup {
+                    break bb;
+                }
+                bb = parent;
+            };
+            for bb in dom_path.drain(..) {
+                post_contract_node.insert(bb, root);
+            }
+            root
+        };
+
+        let mut parent = IndexVec::from_elem(None, &self.body.basic_blocks);
+        for (bb, bb_data) in self.body.basic_blocks.iter_enumerated() {
+            if !bb_data.is_cleanup || !self.reachable_blocks.contains(bb) {
+                continue;
+            }
+            let bb = get_post_contract_node(bb);
+            for s in bb_data.terminator().successors() {
+                let s = get_post_contract_node(s);
+                if s == bb {
+                    continue;
+                }
+                let parent = &mut parent[bb];
+                match parent {
+                    None => {
+                        *parent = Some(s);
+                    }
+                    Some(e) if *e == s => (),
+                    Some(e) => self.fail(
+                        Location { block: bb, statement_index: 0 },
+                        format!(
+                            "Cleanup control flow violation: The blocks dominated by {:?} have edges to both {:?} and {:?}",
+                            bb,
+                            s,
+                            *e
+                        )
+                    ),
+                }
+            }
+        }
+
+        // Check for cycles
+        let mut stack = FxHashSet::default();
+        for i in 0..parent.len() {
+            let mut bb = BasicBlock::from_usize(i);
+            stack.clear();
+            stack.insert(bb);
+            loop {
+                let Some(parent)= parent[bb].take() else {
+                    break
+                };
+                let no_cycle = stack.insert(parent);
+                if !no_cycle {
+                    self.fail(
+                        Location { block: bb, statement_index: 0 },
+                        format!(
+                            "Cleanup control flow violation: Cycle involving edge {:?} -> {:?}",
+                            bb, parent,
+                        ),
+                    );
+                    break;
+                }
+                bb = parent;
+            }
+        }
+    }
+
     /// Check if src can be assigned into dest.
     /// This is not precise, it will accept some incorrect assignments.
     fn mir_assign_valid_types(&self, src: Ty<'tcx>, dest: Ty<'tcx>) -> bool {
diff --git a/compiler/rustc_data_structures/src/fx.rs b/compiler/rustc_data_structures/src/fx.rs
index 0d0c51b6819..9fce0e1e65c 100644
--- a/compiler/rustc_data_structures/src/fx.rs
+++ b/compiler/rustc_data_structures/src/fx.rs
@@ -11,8 +11,8 @@ pub type IndexEntry<'a, K, V> = indexmap::map::Entry<'a, K, V>;
 #[macro_export]
 macro_rules! define_id_collections {
     ($map_name:ident, $set_name:ident, $entry_name:ident, $key:ty) => {
-        pub type $map_name<T> = $crate::fx::FxHashMap<$key, T>;
-        pub type $set_name = $crate::fx::FxHashSet<$key>;
+        pub type $map_name<T> = $crate::unord::UnordMap<$key, T>;
+        pub type $set_name = $crate::unord::UnordSet<$key>;
         pub type $entry_name<'a, T> = $crate::fx::StdEntry<'a, $key, T>;
     };
 }
diff --git a/compiler/rustc_data_structures/src/graph/dominators/mod.rs b/compiler/rustc_data_structures/src/graph/dominators/mod.rs
index ea2a4388b92..471457f61b2 100644
--- a/compiler/rustc_data_structures/src/graph/dominators/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/dominators/mod.rs
@@ -135,7 +135,10 @@ pub fn dominators<G: ControlFlowGraph>(graph: G) -> Dominators<G::Node> {
         // This loop computes the semi[w] for w.
         semi[w] = w;
         for v in graph.predecessors(pre_order_to_real[w]) {
-            let v = real_to_pre_order[v].unwrap();
+            // Reachable vertices may have unreachable predecessors, so ignore any of them
+            let Some(v) = real_to_pre_order[v] else {
+                continue
+            };
 
             // eval returns a vertex x from which semi[x] is minimum among
             // vertices semi[v] +> x *> v.
@@ -268,10 +271,6 @@ pub struct Dominators<N: Idx> {
 }
 
 impl<Node: Idx> Dominators<Node> {
-    pub fn dummy() -> Self {
-        Self { post_order_rank: IndexVec::new(), immediate_dominators: IndexVec::new() }
-    }
-
     pub fn is_reachable(&self, node: Node) -> bool {
         self.immediate_dominators[node].is_some()
     }
@@ -296,7 +295,7 @@ impl<Node: Idx> Dominators<Node> {
     /// of two unrelated nodes will also be consistent, but otherwise the order has no
     /// meaning.) This method cannot be used to determine if either Node dominates the other.
     pub fn rank_partial_cmp(&self, lhs: Node, rhs: Node) -> Option<Ordering> {
-        self.post_order_rank[lhs].partial_cmp(&self.post_order_rank[rhs])
+        self.post_order_rank[rhs].partial_cmp(&self.post_order_rank[lhs])
     }
 }
 
diff --git a/compiler/rustc_data_structures/src/graph/implementation/tests.rs b/compiler/rustc_data_structures/src/graph/implementation/tests.rs
index e4e4d0d44ba..dc1ce1747bf 100644
--- a/compiler/rustc_data_structures/src/graph/implementation/tests.rs
+++ b/compiler/rustc_data_structures/src/graph/implementation/tests.rs
@@ -70,8 +70,8 @@ fn test_adjacent_edges<N: PartialEq + Debug, E: PartialEq + Debug>(
             "counter={:?} expected={:?} edge_index={:?} edge={:?}",
             counter, expected_incoming[counter], edge_index, edge
         );
-        match expected_incoming[counter] {
-            (ref e, ref n) => {
+        match &expected_incoming[counter] {
+            (e, n) => {
                 assert!(e == &edge.data);
                 assert!(n == graph.node_data(edge.source()));
                 assert!(start_index == edge.target);
@@ -88,8 +88,8 @@ fn test_adjacent_edges<N: PartialEq + Debug, E: PartialEq + Debug>(
             "counter={:?} expected={:?} edge_index={:?} edge={:?}",
             counter, expected_outgoing[counter], edge_index, edge
         );
-        match expected_outgoing[counter] {
-            (ref e, ref n) => {
+        match &expected_outgoing[counter] {
+            (e, n) => {
                 assert!(e == &edge.data);
                 assert!(start_index == edge.source);
                 assert!(n == graph.node_data(edge.target));
diff --git a/compiler/rustc_data_structures/src/graph/iterate/mod.rs b/compiler/rustc_data_structures/src/graph/iterate/mod.rs
index 57007611a76..8a9af300c06 100644
--- a/compiler/rustc_data_structures/src/graph/iterate/mod.rs
+++ b/compiler/rustc_data_structures/src/graph/iterate/mod.rs
@@ -317,12 +317,12 @@ where
         _node: G::Node,
         _prior_status: Option<NodeStatus>,
     ) -> ControlFlow<Self::BreakVal> {
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 
     /// Called after all nodes reachable from this one have been examined.
     fn node_settled(&mut self, _node: G::Node) -> ControlFlow<Self::BreakVal> {
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 
     /// Behave as if no edges exist from `source` to `target`.
@@ -346,8 +346,8 @@ where
         prior_status: Option<NodeStatus>,
     ) -> ControlFlow<Self::BreakVal> {
         match prior_status {
-            Some(NodeStatus::Visited) => ControlFlow::BREAK,
-            _ => ControlFlow::CONTINUE,
+            Some(NodeStatus::Visited) => ControlFlow::Break(()),
+            _ => ControlFlow::Continue(()),
         }
     }
 }
diff --git a/compiler/rustc_data_structures/src/lib.rs b/compiler/rustc_data_structures/src/lib.rs
index 3a2000233c5..954e84c303b 100644
--- a/compiler/rustc_data_structures/src/lib.rs
+++ b/compiler/rustc_data_structures/src/lib.rs
@@ -11,7 +11,6 @@
 #![feature(associated_type_bounds)]
 #![feature(auto_traits)]
 #![feature(cell_leak)]
-#![feature(control_flow_enum)]
 #![feature(extend_one)]
 #![feature(hash_raw_entry)]
 #![feature(hasher_prefixfree_extras)]
diff --git a/compiler/rustc_data_structures/src/sorted_map.rs b/compiler/rustc_data_structures/src/sorted_map.rs
index c63caa06818..9409057d484 100644
--- a/compiler/rustc_data_structures/src/sorted_map.rs
+++ b/compiler/rustc_data_structures/src/sorted_map.rs
@@ -1,6 +1,5 @@
 use crate::stable_hasher::{HashStable, StableHasher, StableOrd};
 use std::borrow::Borrow;
-use std::cmp::Ordering;
 use std::fmt::Debug;
 use std::mem;
 use std::ops::{Bound, Index, IndexMut, RangeBounds};
@@ -171,7 +170,7 @@ impl<K: Ord, V> SortedMap<K, V> {
     where
         F: Fn(&mut K),
     {
-        self.data.iter_mut().map(|&mut (ref mut k, _)| k).for_each(f);
+        self.data.iter_mut().map(|(k, _)| k).for_each(f);
     }
 
     /// Inserts a presorted range of elements into the map. If the range can be
@@ -232,10 +231,10 @@ impl<K: Ord, V> SortedMap<K, V> {
         R: RangeBounds<K>,
     {
         let start = match range.start_bound() {
-            Bound::Included(ref k) => match self.lookup_index_for(k) {
+            Bound::Included(k) => match self.lookup_index_for(k) {
                 Ok(index) | Err(index) => index,
             },
-            Bound::Excluded(ref k) => match self.lookup_index_for(k) {
+            Bound::Excluded(k) => match self.lookup_index_for(k) {
                 Ok(index) => index + 1,
                 Err(index) => index,
             },
@@ -243,11 +242,11 @@ impl<K: Ord, V> SortedMap<K, V> {
         };
 
         let end = match range.end_bound() {
-            Bound::Included(ref k) => match self.lookup_index_for(k) {
+            Bound::Included(k) => match self.lookup_index_for(k) {
                 Ok(index) => index + 1,
                 Err(index) => index,
             },
-            Bound::Excluded(ref k) => match self.lookup_index_for(k) {
+            Bound::Excluded(k) => match self.lookup_index_for(k) {
                 Ok(index) | Err(index) => index,
             },
             Bound::Unbounded => self.data.len(),
@@ -302,7 +301,7 @@ impl<K: Ord, V> FromIterator<(K, V)> for SortedMap<K, V> {
         let mut data: Vec<(K, V)> = iter.into_iter().collect();
 
         data.sort_unstable_by(|(k1, _), (k2, _)| k1.cmp(k2));
-        data.dedup_by(|&mut (ref k1, _), &mut (ref k2, _)| k1.cmp(k2) == Ordering::Equal);
+        data.dedup_by(|(k1, _), (k2, _)| k1 == k2);
 
         SortedMap { data }
     }
diff --git a/compiler/rustc_data_structures/src/sorted_map/index_map.rs b/compiler/rustc_data_structures/src/sorted_map/index_map.rs
index 7af5c14942a..814e7c7fb9b 100644
--- a/compiler/rustc_data_structures/src/sorted_map/index_map.rs
+++ b/compiler/rustc_data_structures/src/sorted_map/index_map.rs
@@ -63,13 +63,13 @@ impl<I: Idx, K: Ord, V> SortedIndexMultiMap<I, K, V> {
     /// Returns an iterator over the items in the map in insertion order.
     #[inline]
     pub fn iter(&self) -> impl '_ + DoubleEndedIterator<Item = (&K, &V)> {
-        self.items.iter().map(|(ref k, ref v)| (k, v))
+        self.items.iter().map(|(k, v)| (k, v))
     }
 
     /// Returns an iterator over the items in the map in insertion order along with their indices.
     #[inline]
     pub fn iter_enumerated(&self) -> impl '_ + DoubleEndedIterator<Item = (I, (&K, &V))> {
-        self.items.iter_enumerated().map(|(i, (ref k, ref v))| (i, (k, v)))
+        self.items.iter_enumerated().map(|(i, (k, v))| (i, (k, v)))
     }
 
     /// Returns the item in the map with the given index.
diff --git a/compiler/rustc_data_structures/src/sorted_map/tests.rs b/compiler/rustc_data_structures/src/sorted_map/tests.rs
index 1e977d709f1..3cc250862df 100644
--- a/compiler/rustc_data_structures/src/sorted_map/tests.rs
+++ b/compiler/rustc_data_structures/src/sorted_map/tests.rs
@@ -6,7 +6,7 @@ fn test_sorted_index_multi_map() {
     let set: SortedIndexMultiMap<usize, _, _> = entries.iter().copied().collect();
 
     // Insertion order is preserved.
-    assert!(entries.iter().map(|(ref k, ref v)| (k, v)).eq(set.iter()));
+    assert!(entries.iter().map(|(k, v)| (k, v)).eq(set.iter()));
 
     // Indexing
     for (i, expect) in entries.iter().enumerate() {
diff --git a/compiler/rustc_data_structures/src/tiny_list.rs b/compiler/rustc_data_structures/src/tiny_list.rs
index 9b07f86846e..11a408f216a 100644
--- a/compiler/rustc_data_structures/src/tiny_list.rs
+++ b/compiler/rustc_data_structures/src/tiny_list.rs
@@ -37,9 +37,9 @@ impl<T: PartialEq> TinyList<T> {
 
     #[inline]
     pub fn remove(&mut self, data: &T) -> bool {
-        self.head = match self.head {
-            Some(ref mut head) if head.data == *data => head.next.take().map(|x| *x),
-            Some(ref mut head) => return head.remove_next(data),
+        self.head = match &mut self.head {
+            Some(head) if head.data == *data => head.next.take().map(|x| *x),
+            Some(head) => return head.remove_next(data),
             None => return false,
         };
         true
@@ -48,7 +48,7 @@ impl<T: PartialEq> TinyList<T> {
     #[inline]
     pub fn contains(&self, data: &T) -> bool {
         let mut elem = self.head.as_ref();
-        while let Some(ref e) = elem {
+        while let Some(e) = elem {
             if &e.data == data {
                 return true;
             }
@@ -65,15 +65,14 @@ struct Element<T> {
 }
 
 impl<T: PartialEq> Element<T> {
-    fn remove_next(&mut self, data: &T) -> bool {
-        let mut n = self;
+    fn remove_next(mut self: &mut Self, data: &T) -> bool {
         loop {
-            match n.next {
+            match self.next {
                 Some(ref mut next) if next.data == *data => {
-                    n.next = next.next.take();
+                    self.next = next.next.take();
                     return true;
                 }
-                Some(ref mut next) => n = next,
+                Some(ref mut next) => self = next,
                 None => return false,
             }
         }
diff --git a/compiler/rustc_data_structures/src/tiny_list/tests.rs b/compiler/rustc_data_structures/src/tiny_list/tests.rs
index c0334d2e23e..4b95e62bef0 100644
--- a/compiler/rustc_data_structures/src/tiny_list/tests.rs
+++ b/compiler/rustc_data_structures/src/tiny_list/tests.rs
@@ -6,7 +6,7 @@ use test::{black_box, Bencher};
 impl<T> TinyList<T> {
     fn len(&self) -> usize {
         let (mut elem, mut count) = (self.head.as_ref(), 0);
-        while let Some(ref e) = elem {
+        while let Some(e) = elem {
             count += 1;
             elem = e.next.as_deref();
         }
diff --git a/compiler/rustc_data_structures/src/unord.rs b/compiler/rustc_data_structures/src/unord.rs
index 14257e4d5c6..f35f18e51cb 100644
--- a/compiler/rustc_data_structures/src/unord.rs
+++ b/compiler/rustc_data_structures/src/unord.rs
@@ -6,13 +6,15 @@ use rustc_hash::{FxHashMap, FxHashSet};
 use smallvec::SmallVec;
 use std::{
     borrow::Borrow,
+    collections::hash_map::Entry,
     hash::Hash,
     iter::{Product, Sum},
+    ops::Index,
 };
 
 use crate::{
     fingerprint::Fingerprint,
-    stable_hasher::{HashStable, StableHasher, ToStableHashKey},
+    stable_hasher::{HashStable, StableHasher, StableOrd, ToStableHashKey},
 };
 
 /// `UnordItems` is the order-less version of `Iterator`. It only contains methods
@@ -38,17 +40,17 @@ impl<T, I: Iterator<Item = T>> UnordItems<T, I> {
     }
 
     #[inline]
-    pub fn all<U, F: Fn(T) -> bool>(mut self, f: F) -> bool {
+    pub fn all<F: Fn(T) -> bool>(mut self, f: F) -> bool {
         self.0.all(f)
     }
 
     #[inline]
-    pub fn any<U, F: Fn(T) -> bool>(mut self, f: F) -> bool {
+    pub fn any<F: Fn(T) -> bool>(mut self, f: F) -> bool {
         self.0.any(f)
     }
 
     #[inline]
-    pub fn filter<U, F: Fn(&T) -> bool>(self, f: F) -> UnordItems<T, impl Iterator<Item = T>> {
+    pub fn filter<F: Fn(&T) -> bool>(self, f: F) -> UnordItems<T, impl Iterator<Item = T>> {
         UnordItems(self.0.filter(f))
     }
 
@@ -96,6 +98,15 @@ impl<T, I: Iterator<Item = T>> UnordItems<T, I> {
     pub fn count(self) -> usize {
         self.0.count()
     }
+
+    #[inline]
+    pub fn flat_map<U, F, O>(self, f: F) -> UnordItems<O, impl Iterator<Item = O>>
+    where
+        U: IntoIterator<Item = O>,
+        F: Fn(T) -> U,
+    {
+        UnordItems(self.0.flat_map(f))
+    }
 }
 
 impl<'a, T: Clone + 'a, I: Iterator<Item = &'a T>> UnordItems<&'a T, I> {
@@ -147,6 +158,7 @@ pub struct UnordSet<V: Eq + Hash> {
 }
 
 impl<V: Eq + Hash> Default for UnordSet<V> {
+    #[inline]
     fn default() -> Self {
         Self { inner: FxHashSet::default() }
     }
@@ -178,7 +190,16 @@ impl<V: Eq + Hash> UnordSet<V> {
     }
 
     #[inline]
-    pub fn items(&self) -> UnordItems<&V, impl Iterator<Item = &V>> {
+    pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> bool
+    where
+        V: Borrow<Q>,
+        Q: Hash + Eq,
+    {
+        self.inner.remove(k)
+    }
+
+    #[inline]
+    pub fn items<'a>(&'a self) -> UnordItems<&'a V, impl Iterator<Item = &'a V>> {
         UnordItems(self.inner.iter())
     }
 
@@ -187,20 +208,75 @@ impl<V: Eq + Hash> UnordSet<V> {
         UnordItems(self.inner.into_iter())
     }
 
+    /// Returns the items of this set in stable sort order (as defined by `ToStableHashKey`).
+    ///
+    /// The `cache_sort_key` parameter controls if [slice::sort_by_cached_key] or
+    /// [slice::sort_unstable_by_key] will be used for sorting the vec. Use
+    /// `cache_sort_key` when the [ToStableHashKey::to_stable_hash_key] implementation
+    /// for `V` is expensive (e.g. a `DefId -> DefPathHash` lookup).
+    #[inline]
+    pub fn to_sorted<HCX>(&self, hcx: &HCX, cache_sort_key: bool) -> Vec<&V>
+    where
+        V: ToStableHashKey<HCX>,
+    {
+        to_sorted_vec(hcx, self.inner.iter(), cache_sort_key, |&x| x)
+    }
+
+    /// Returns the items of this set in stable sort order (as defined by
+    /// `StableOrd`). This method is much more efficient than
+    /// `into_sorted` because it does not need to transform keys to their
+    /// `ToStableHashKey` equivalent.
+    #[inline]
+    pub fn to_sorted_stable_ord(&self) -> Vec<V>
+    where
+        V: Ord + StableOrd + Copy,
+    {
+        let mut items: Vec<V> = self.inner.iter().copied().collect();
+        items.sort_unstable();
+        items
+    }
+
+    /// Returns the items of this set in stable sort order (as defined by `ToStableHashKey`).
+    ///
+    /// The `cache_sort_key` parameter controls if [slice::sort_by_cached_key] or
+    /// [slice::sort_unstable_by_key] will be used for sorting the vec. Use
+    /// `cache_sort_key` when the [ToStableHashKey::to_stable_hash_key] implementation
+    /// for `V` is expensive (e.g. a `DefId -> DefPathHash` lookup).
+    #[inline]
+    pub fn into_sorted<HCX>(self, hcx: &HCX, cache_sort_key: bool) -> Vec<V>
+    where
+        V: ToStableHashKey<HCX>,
+    {
+        to_sorted_vec(hcx, self.inner.into_iter(), cache_sort_key, |x| x)
+    }
+
     // We can safely extend this UnordSet from a set of unordered values because that
     // won't expose the internal ordering anywhere.
     #[inline]
     pub fn extend<I: Iterator<Item = V>>(&mut self, items: UnordItems<V, I>) {
         self.inner.extend(items.0)
     }
+
+    #[inline]
+    pub fn clear(&mut self) {
+        self.inner.clear();
+    }
 }
 
 impl<V: Hash + Eq> Extend<V> for UnordSet<V> {
+    #[inline]
     fn extend<T: IntoIterator<Item = V>>(&mut self, iter: T) {
         self.inner.extend(iter)
     }
 }
 
+impl<V: Hash + Eq> FromIterator<V> for UnordSet<V> {
+    #[inline]
+    fn from_iter<T: IntoIterator<Item = V>>(iter: T) -> Self {
+        UnordSet { inner: FxHashSet::from_iter(iter) }
+    }
+}
+
 impl<HCX, V: Hash + Eq + HashStable<HCX>> HashStable<HCX> for UnordSet<V> {
     #[inline]
     fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) {
@@ -223,17 +299,33 @@ pub struct UnordMap<K: Eq + Hash, V> {
 }
 
 impl<K: Eq + Hash, V> Default for UnordMap<K, V> {
+    #[inline]
     fn default() -> Self {
         Self { inner: FxHashMap::default() }
     }
 }
 
 impl<K: Hash + Eq, V> Extend<(K, V)> for UnordMap<K, V> {
+    #[inline]
     fn extend<T: IntoIterator<Item = (K, V)>>(&mut self, iter: T) {
         self.inner.extend(iter)
     }
 }
 
+impl<K: Hash + Eq, V> FromIterator<(K, V)> for UnordMap<K, V> {
+    #[inline]
+    fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> Self {
+        UnordMap { inner: FxHashMap::from_iter(iter) }
+    }
+}
+
+impl<K: Hash + Eq, V, I: Iterator<Item = (K, V)>> From<UnordItems<(K, V), I>> for UnordMap<K, V> {
+    #[inline]
+    fn from(items: UnordItems<(K, V), I>) -> Self {
+        UnordMap { inner: FxHashMap::from_iter(items.0) }
+    }
+}
+
 impl<K: Eq + Hash, V> UnordMap<K, V> {
     #[inline]
     pub fn len(&self) -> usize {
@@ -255,7 +347,44 @@ impl<K: Eq + Hash, V> UnordMap<K, V> {
     }
 
     #[inline]
-    pub fn items(&self) -> UnordItems<(&K, &V), impl Iterator<Item = (&K, &V)>> {
+    pub fn is_empty(&self) -> bool {
+        self.inner.is_empty()
+    }
+
+    #[inline]
+    pub fn entry(&mut self, key: K) -> Entry<'_, K, V> {
+        self.inner.entry(key)
+    }
+
+    #[inline]
+    pub fn get<Q: ?Sized>(&self, k: &Q) -> Option<&V>
+    where
+        K: Borrow<Q>,
+        Q: Hash + Eq,
+    {
+        self.inner.get(k)
+    }
+
+    #[inline]
+    pub fn get_mut<Q: ?Sized>(&mut self, k: &Q) -> Option<&mut V>
+    where
+        K: Borrow<Q>,
+        Q: Hash + Eq,
+    {
+        self.inner.get_mut(k)
+    }
+
+    #[inline]
+    pub fn remove<Q: ?Sized>(&mut self, k: &Q) -> Option<V>
+    where
+        K: Borrow<Q>,
+        Q: Hash + Eq,
+    {
+        self.inner.remove(k)
+    }
+
+    #[inline]
+    pub fn items<'a>(&'a self) -> UnordItems<(&'a K, &'a V), impl Iterator<Item = (&'a K, &'a V)>> {
         UnordItems(self.inner.iter())
     }
 
@@ -270,6 +399,77 @@ impl<K: Eq + Hash, V> UnordMap<K, V> {
     pub fn extend<I: Iterator<Item = (K, V)>>(&mut self, items: UnordItems<(K, V), I>) {
         self.inner.extend(items.0)
     }
+
+    /// Returns the entries of this map in stable sort order (as defined by `ToStableHashKey`).
+    ///
+    /// The `cache_sort_key` parameter controls if [slice::sort_by_cached_key] or
+    /// [slice::sort_unstable_by_key] will be used for sorting the vec. Use
+    /// `cache_sort_key` when the [ToStableHashKey::to_stable_hash_key] implementation
+    /// for `K` is expensive (e.g. a `DefId -> DefPathHash` lookup).
+    #[inline]
+    pub fn to_sorted<HCX>(&self, hcx: &HCX, cache_sort_key: bool) -> Vec<(&K, &V)>
+    where
+        K: ToStableHashKey<HCX>,
+    {
+        to_sorted_vec(hcx, self.inner.iter(), cache_sort_key, |&(k, _)| k)
+    }
+
+    /// Returns the entries of this map in stable sort order (as defined by `StableOrd`).
+    /// This method can be much more efficient than `into_sorted` because it does not need
+    /// to transform keys to their `ToStableHashKey` equivalent.
+    #[inline]
+    pub fn to_sorted_stable_ord(&self) -> Vec<(K, &V)>
+    where
+        K: Ord + StableOrd + Copy,
+    {
+        let mut items: Vec<(K, &V)> = self.inner.iter().map(|(&k, v)| (k, v)).collect();
+        items.sort_unstable_by_key(|&(k, _)| k);
+        items
+    }
+
+    /// Returns the entries of this map in stable sort order (as defined by `ToStableHashKey`).
+    ///
+    /// The `cache_sort_key` parameter controls if [slice::sort_by_cached_key] or
+    /// [slice::sort_unstable_by_key] will be used for sorting the vec. Use
+    /// `cache_sort_key` when the [ToStableHashKey::to_stable_hash_key] implementation
+    /// for `K` is expensive (e.g. a `DefId -> DefPathHash` lookup).
+    #[inline]
+    pub fn into_sorted<HCX>(self, hcx: &HCX, cache_sort_key: bool) -> Vec<(K, V)>
+    where
+        K: ToStableHashKey<HCX>,
+    {
+        to_sorted_vec(hcx, self.inner.into_iter(), cache_sort_key, |(k, _)| k)
+    }
+
+    /// Returns the values of this map in stable sort order (as defined by K's
+    /// `ToStableHashKey` implementation).
+    ///
+    /// The `cache_sort_key` parameter controls if [slice::sort_by_cached_key] or
+    /// [slice::sort_unstable_by_key] will be used for sorting the vec. Use
+    /// `cache_sort_key` when the [ToStableHashKey::to_stable_hash_key] implementation
+    /// for `K` is expensive (e.g. a `DefId -> DefPathHash` lookup).
+    #[inline]
+    pub fn values_sorted<HCX>(&self, hcx: &HCX, cache_sort_key: bool) -> impl Iterator<Item = &V>
+    where
+        K: ToStableHashKey<HCX>,
+    {
+        to_sorted_vec(hcx, self.inner.iter(), cache_sort_key, |&(k, _)| k)
+            .into_iter()
+            .map(|(_, v)| v)
+    }
+}
+
+impl<K, Q: ?Sized, V> Index<&Q> for UnordMap<K, V>
+where
+    K: Eq + Hash + Borrow<Q>,
+    Q: Eq + Hash,
+{
+    type Output = V;
+
+    #[inline]
+    fn index(&self, key: &Q) -> &V {
+        &self.inner[key]
+    }
 }
 
 impl<HCX, K: Hash + Eq + HashStable<HCX>, V: HashStable<HCX>> HashStable<HCX> for UnordMap<K, V> {
@@ -334,6 +534,12 @@ impl<T> Extend<T> for UnordBag<T> {
     }
 }
 
+impl<T, I: Iterator<Item = T>> From<UnordItems<T, I>> for UnordBag<T> {
+    fn from(value: UnordItems<T, I>) -> Self {
+        UnordBag { inner: Vec::from_iter(value.0) }
+    }
+}
+
 impl<HCX, V: Hash + Eq + HashStable<HCX>> HashStable<HCX> for UnordBag<V> {
     #[inline]
     fn hash_stable(&self, hcx: &mut HCX, hasher: &mut StableHasher) {
@@ -341,6 +547,27 @@ impl<HCX, V: Hash + Eq + HashStable<HCX>> HashStable<HCX> for UnordBag<V> {
     }
 }
 
+#[inline]
+fn to_sorted_vec<HCX, T, K, I>(
+    hcx: &HCX,
+    iter: I,
+    cache_sort_key: bool,
+    extract_key: fn(&T) -> &K,
+) -> Vec<T>
+where
+    I: Iterator<Item = T>,
+    K: ToStableHashKey<HCX>,
+{
+    let mut items: Vec<T> = iter.collect();
+    if cache_sort_key {
+        items.sort_by_cached_key(|x| extract_key(x).to_stable_hash_key(hcx));
+    } else {
+        items.sort_unstable_by_key(|x| extract_key(x).to_stable_hash_key(hcx));
+    }
+
+    items
+}
+
 fn hash_iter_order_independent<
     HCX,
     T: HashStable<HCX>,
diff --git a/compiler/rustc_driver/src/lib.rs b/compiler/rustc_driver/src/lib.rs
index a62e5dec4b8..f50ad0137b8 100644
--- a/compiler/rustc_driver/src/lib.rs
+++ b/compiler/rustc_driver/src/lib.rs
@@ -219,7 +219,6 @@ fn run_compiler(
         crate_cfg: cfg,
         crate_check_cfg: check_cfg,
         input: Input::File(PathBuf::new()),
-        input_path: None,
         output_file: ofile,
         output_dir: odir,
         file_loader,
@@ -237,9 +236,8 @@ fn run_compiler(
 
     match make_input(config.opts.error_format, &matches.free) {
         Err(reported) => return Err(reported),
-        Ok(Some((input, input_file_path))) => {
+        Ok(Some(input)) => {
             config.input = input;
-            config.input_path = input_file_path;
 
             callbacks.config(&mut config);
         }
@@ -261,14 +259,8 @@ fn run_compiler(
                         describe_lints(compiler.session(), &lint_store, registered_lints);
                         return;
                     }
-                    let should_stop = print_crate_info(
-                        &***compiler.codegen_backend(),
-                        compiler.session(),
-                        None,
-                        compiler.output_dir(),
-                        compiler.output_file(),
-                        compiler.temps_dir(),
-                    );
+                    let should_stop =
+                        print_crate_info(&***compiler.codegen_backend(), compiler.session(), false);
 
                     if should_stop == Compilation::Stop {
                         return;
@@ -290,18 +282,9 @@ fn run_compiler(
 
     interface::run_compiler(config, |compiler| {
         let sess = compiler.session();
-        let should_stop = print_crate_info(
-            &***compiler.codegen_backend(),
-            sess,
-            Some(compiler.input()),
-            compiler.output_dir(),
-            compiler.output_file(),
-            compiler.temps_dir(),
-        )
-        .and_then(|| {
-            list_metadata(sess, &*compiler.codegen_backend().metadata_loader(), compiler.input())
-        })
-        .and_then(|| try_process_rlink(sess, compiler));
+        let should_stop = print_crate_info(&***compiler.codegen_backend(), sess, true)
+            .and_then(|| list_metadata(sess, &*compiler.codegen_backend().metadata_loader()))
+            .and_then(|| try_process_rlink(sess, compiler));
 
         if should_stop == Compilation::Stop {
             return sess.compile_status();
@@ -315,24 +298,12 @@ fn run_compiler(
                 if ppm.needs_ast_map() {
                     let expanded_crate = queries.expansion()?.borrow().0.clone();
                     queries.global_ctxt()?.enter(|tcx| {
-                        pretty::print_after_hir_lowering(
-                            tcx,
-                            compiler.input(),
-                            &*expanded_crate,
-                            *ppm,
-                            compiler.output_file().as_deref(),
-                        );
+                        pretty::print_after_hir_lowering(tcx, &*expanded_crate, *ppm);
                         Ok(())
                     })?;
                 } else {
                     let krate = queries.parse()?.steal();
-                    pretty::print_after_parsing(
-                        sess,
-                        compiler.input(),
-                        &krate,
-                        *ppm,
-                        compiler.output_file().as_deref(),
-                    );
+                    pretty::print_after_parsing(sess, &krate, *ppm);
                 }
                 trace!("finished pretty-printing");
                 return early_exit();
@@ -357,21 +328,17 @@ fn run_compiler(
                 }
             }
 
-            queries.expansion()?;
+            queries.global_ctxt()?;
             if callbacks.after_expansion(compiler, queries) == Compilation::Stop {
                 return early_exit();
             }
 
-            queries.prepare_outputs()?;
-
             if sess.opts.output_types.contains_key(&OutputType::DepInfo)
                 && sess.opts.output_types.len() == 1
             {
                 return early_exit();
             }
 
-            queries.global_ctxt()?;
-
             if sess.opts.unstable_opts.no_analysis {
                 return early_exit();
             }
@@ -384,9 +351,9 @@ fn run_compiler(
                         save::process_crate(
                             tcx,
                             crate_name,
-                            compiler.input(),
+                            &sess.io.input,
                             None,
-                            DumpHandler::new(compiler.output_dir().as_deref(), crate_name),
+                            DumpHandler::new(sess.io.output_dir.as_deref(), crate_name),
                         )
                     });
                 }
@@ -439,7 +406,7 @@ fn make_output(matches: &getopts::Matches) -> (Option<PathBuf>, Option<PathBuf>)
 fn make_input(
     error_format: ErrorOutputType,
     free_matches: &[String],
-) -> Result<Option<(Input, Option<PathBuf>)>, ErrorGuaranteed> {
+) -> Result<Option<Input>, ErrorGuaranteed> {
     if free_matches.len() == 1 {
         let ifile = &free_matches[0];
         if ifile == "-" {
@@ -461,12 +428,12 @@ fn make_input(
                 let line = isize::from_str_radix(&line, 10)
                     .expect("UNSTABLE_RUSTDOC_TEST_LINE needs to be an number");
                 let file_name = FileName::doc_test_source_code(PathBuf::from(path), line);
-                Ok(Some((Input::Str { name: file_name, input: src }, None)))
+                Ok(Some(Input::Str { name: file_name, input: src }))
             } else {
-                Ok(Some((Input::Str { name: FileName::anon_source_code(&src), input: src }, None)))
+                Ok(Some(Input::Str { name: FileName::anon_source_code(&src), input: src }))
             }
         } else {
-            Ok(Some((Input::File(PathBuf::from(ifile)), Some(PathBuf::from(ifile)))))
+            Ok(Some(Input::File(PathBuf::from(ifile))))
         }
     } else {
         Ok(None)
@@ -560,7 +527,7 @@ fn show_content_with_pager(content: &str) {
 
 pub fn try_process_rlink(sess: &Session, compiler: &interface::Compiler) -> Compilation {
     if sess.opts.unstable_opts.link_only {
-        if let Input::File(file) = compiler.input() {
+        if let Input::File(file) = &sess.io.input {
             // FIXME: #![crate_type] and #![crate_name] support not implemented yet
             sess.init_crate_types(collect_crate_types(sess, &[]));
             let outputs = compiler.build_output_filenames(sess, &[]);
@@ -601,13 +568,9 @@ pub fn try_process_rlink(sess: &Session, compiler: &interface::Compiler) -> Comp
     }
 }
 
-pub fn list_metadata(
-    sess: &Session,
-    metadata_loader: &dyn MetadataLoader,
-    input: &Input,
-) -> Compilation {
+pub fn list_metadata(sess: &Session, metadata_loader: &dyn MetadataLoader) -> Compilation {
     if sess.opts.unstable_opts.ls {
-        match *input {
+        match sess.io.input {
             Input::File(ref ifile) => {
                 let path = &(*ifile);
                 let mut v = Vec::new();
@@ -627,10 +590,7 @@ pub fn list_metadata(
 fn print_crate_info(
     codegen_backend: &dyn CodegenBackend,
     sess: &Session,
-    input: Option<&Input>,
-    odir: &Option<PathBuf>,
-    ofile: &Option<PathBuf>,
-    temps_dir: &Option<PathBuf>,
+    parse_attrs: bool,
 ) -> Compilation {
     use rustc_session::config::PrintRequest::*;
     // NativeStaticLibs and LinkArgs are special - printed during linking
@@ -639,18 +599,17 @@ fn print_crate_info(
         return Compilation::Continue;
     }
 
-    let attrs = match input {
-        None => None,
-        Some(input) => {
-            let result = parse_crate_attrs(sess, input);
-            match result {
-                Ok(attrs) => Some(attrs),
-                Err(mut parse_error) => {
-                    parse_error.emit();
-                    return Compilation::Stop;
-                }
+    let attrs = if parse_attrs {
+        let result = parse_crate_attrs(sess);
+        match result {
+            Ok(attrs) => Some(attrs),
+            Err(mut parse_error) => {
+                parse_error.emit();
+                return Compilation::Stop;
             }
         }
+    } else {
+        None
     };
     for req in &sess.opts.prints {
         match *req {
@@ -665,14 +624,9 @@ fn print_crate_info(
                 println!("{}", serde_json::to_string_pretty(&sess.target.to_json()).unwrap());
             }
             FileNames | CrateName => {
-                let input = input.unwrap_or_else(|| {
-                    early_error(ErrorOutputType::default(), "no input file provided")
-                });
                 let attrs = attrs.as_ref().unwrap();
-                let t_outputs = rustc_interface::util::build_output_filenames(
-                    input, odir, ofile, temps_dir, attrs, sess,
-                );
-                let id = rustc_session::output::find_crate_name(sess, attrs, input);
+                let t_outputs = rustc_interface::util::build_output_filenames(attrs, sess);
+                let id = rustc_session::output::find_crate_name(sess, attrs);
                 if *req == PrintRequest::CrateName {
                     println!("{id}");
                     continue;
@@ -1108,8 +1062,8 @@ pub fn handle_options(args: &[String]) -> Option<getopts::Matches> {
     Some(matches)
 }
 
-fn parse_crate_attrs<'a>(sess: &'a Session, input: &Input) -> PResult<'a, ast::AttrVec> {
-    match input {
+fn parse_crate_attrs<'a>(sess: &'a Session) -> PResult<'a, ast::AttrVec> {
+    match &sess.io.input {
         Input::File(ifile) => rustc_parse::parse_crate_attrs_from_file(ifile, &sess.parse_sess),
         Input::Str { name, input } => rustc_parse::parse_crate_attrs_from_source_str(
             name.clone(),
diff --git a/compiler/rustc_driver/src/pretty.rs b/compiler/rustc_driver/src/pretty.rs
index b2451bc730f..ae3ac8625b1 100644
--- a/compiler/rustc_driver/src/pretty.rs
+++ b/compiler/rustc_driver/src/pretty.rs
@@ -9,14 +9,13 @@ use rustc_hir_pretty as pprust_hir;
 use rustc_middle::hir::map as hir_map;
 use rustc_middle::mir::{write_mir_graphviz, write_mir_pretty};
 use rustc_middle::ty::{self, TyCtxt};
-use rustc_session::config::{Input, PpAstTreeMode, PpHirMode, PpMode, PpSourceMode};
+use rustc_session::config::{PpAstTreeMode, PpHirMode, PpMode, PpSourceMode};
 use rustc_session::Session;
 use rustc_span::symbol::Ident;
 use rustc_span::FileName;
 
 use std::cell::Cell;
 use std::fmt::Write;
-use std::path::Path;
 
 pub use self::PpMode::*;
 pub use self::PpSourceMode::*;
@@ -345,8 +344,8 @@ impl<'tcx> pprust_hir::PpAnn for TypedAnnotation<'tcx> {
     }
 }
 
-fn get_source(input: &Input, sess: &Session) -> (String, FileName) {
-    let src_name = input.source_name();
+fn get_source(sess: &Session) -> (String, FileName) {
+    let src_name = sess.io.input.source_name();
     let src = String::clone(
         sess.source_map()
             .get_source_file(&src_name)
@@ -358,8 +357,8 @@ fn get_source(input: &Input, sess: &Session) -> (String, FileName) {
     (src, src_name)
 }
 
-fn write_or_print(out: &str, ofile: Option<&Path>, sess: &Session) {
-    match ofile {
+fn write_or_print(out: &str, sess: &Session) {
+    match &sess.io.output_file {
         None => print!("{out}"),
         Some(p) => {
             if let Err(e) = std::fs::write(p, out) {
@@ -372,14 +371,8 @@ fn write_or_print(out: &str, ofile: Option<&Path>, sess: &Session) {
     }
 }
 
-pub fn print_after_parsing(
-    sess: &Session,
-    input: &Input,
-    krate: &ast::Crate,
-    ppm: PpMode,
-    ofile: Option<&Path>,
-) {
-    let (src, src_name) = get_source(input, sess);
+pub fn print_after_parsing(sess: &Session, krate: &ast::Crate, ppm: PpMode) {
+    let (src, src_name) = get_source(sess);
 
     let out = match ppm {
         Source(s) => {
@@ -407,22 +400,16 @@ pub fn print_after_parsing(
         _ => unreachable!(),
     };
 
-    write_or_print(&out, ofile, sess);
+    write_or_print(&out, sess);
 }
 
-pub fn print_after_hir_lowering<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    input: &Input,
-    krate: &ast::Crate,
-    ppm: PpMode,
-    ofile: Option<&Path>,
-) {
+pub fn print_after_hir_lowering<'tcx>(tcx: TyCtxt<'tcx>, krate: &ast::Crate, ppm: PpMode) {
     if ppm.needs_analysis() {
-        abort_on_err(print_with_analysis(tcx, ppm, ofile), tcx.sess);
+        abort_on_err(print_with_analysis(tcx, ppm), tcx.sess);
         return;
     }
 
-    let (src, src_name) = get_source(input, tcx.sess);
+    let (src, src_name) = get_source(tcx.sess);
 
     let out = match ppm {
         Source(s) => {
@@ -474,18 +461,14 @@ pub fn print_after_hir_lowering<'tcx>(
         _ => unreachable!(),
     };
 
-    write_or_print(&out, ofile, tcx.sess);
+    write_or_print(&out, tcx.sess);
 }
 
 // In an ideal world, this would be a public function called by the driver after
 // analysis is performed. However, we want to call `phase_3_run_analysis_passes`
 // with a different callback than the standard driver, so that isn't easy.
 // Instead, we call that function ourselves.
-fn print_with_analysis(
-    tcx: TyCtxt<'_>,
-    ppm: PpMode,
-    ofile: Option<&Path>,
-) -> Result<(), ErrorGuaranteed> {
+fn print_with_analysis(tcx: TyCtxt<'_>, ppm: PpMode) -> Result<(), ErrorGuaranteed> {
     tcx.analysis(())?;
     let out = match ppm {
         Mir => {
@@ -518,7 +501,7 @@ fn print_with_analysis(
         _ => unreachable!(),
     };
 
-    write_or_print(&out, ofile, tcx.sess);
+    write_or_print(&out, tcx.sess);
 
     Ok(())
 }
diff --git a/compiler/rustc_error_codes/src/error_codes.rs b/compiler/rustc_error_codes/src/error_codes.rs
index 2746396b75a..9d5f4ad7520 100644
--- a/compiler/rustc_error_codes/src/error_codes.rs
+++ b/compiler/rustc_error_codes/src/error_codes.rs
@@ -508,6 +508,7 @@ E0787: include_str!("./error_codes/E0787.md"),
 E0788: include_str!("./error_codes/E0788.md"),
 E0790: include_str!("./error_codes/E0790.md"),
 E0791: include_str!("./error_codes/E0791.md"),
+E0792: include_str!("./error_codes/E0792.md"),
 ;
 //  E0006, // merged with E0005
 //  E0008, // cannot bind by-move into a pattern guard
diff --git a/compiler/rustc_error_codes/src/error_codes/E0208.md b/compiler/rustc_error_codes/src/error_codes/E0208.md
index 7edd93e56a9..1ae01106f20 100644
--- a/compiler/rustc_error_codes/src/error_codes/E0208.md
+++ b/compiler/rustc_error_codes/src/error_codes/E0208.md
@@ -1 +1,46 @@
 #### This error code is internal to the compiler and will not be emitted with normal Rust code.
+#### Note: this error code is no longer emitted by the compiler.
+
+This error code shows the variance of a type's generic parameters.
+
+Erroneous code example:
+
+```compile_fail
+// NOTE: this feature is perma-unstable and should *only* be used for
+//       testing purposes.
+#![feature(rustc_attrs)]
+
+#[rustc_variance]
+struct Foo<'a, T> { // error: deliberate error to display type's variance
+    t: &'a mut T,
+}
+```
+
+which produces the following error:
+
+```text
+error: [-, o]
+ --> <anon>:4:1
+  |
+4 | struct Foo<'a, T> {
+  | ^^^^^^^^^^^^^^^^^
+```
+
+*Note that while `#[rustc_variance]` still exists and is used within the*
+*compiler, it no longer is marked as `E0208` and instead has no error code.*
+
+This error is deliberately triggered with the `#[rustc_variance]` attribute
+(`#![feature(rustc_attrs)]` must be enabled) and helps to show you the variance
+of the type's generic parameters. You can read more about variance and
+subtyping in [this section of the Rustnomicon]. For a more in depth look at
+variance (including a more complete list of common variances) see
+[this section of the Reference]. For information on how variance is implemented
+in the compiler, see [this section of `rustc-dev-guide`].
+
+This error can be easily fixed by removing the `#[rustc_variance]` attribute,
+the compiler's suggestion to comment it out can be applied automatically with
+`rustfix`.
+
+[this section of the Rustnomicon]: https://doc.rust-lang.org/nomicon/subtyping.html
+[this section of the Reference]: https://doc.rust-lang.org/reference/subtyping.html#variance
+[this section of `rustc-dev-guide`]: https://rustc-dev-guide.rust-lang.org/variance.html
diff --git a/compiler/rustc_error_codes/src/error_codes/E0792.md b/compiler/rustc_error_codes/src/error_codes/E0792.md
new file mode 100644
index 00000000000..bad2b5abfe4
--- /dev/null
+++ b/compiler/rustc_error_codes/src/error_codes/E0792.md
@@ -0,0 +1,60 @@
+A type alias impl trait can only have its hidden type assigned
+when used fully generically (and within their defining scope).
+This means
+
+```compile_fail,E0792
+#![feature(type_alias_impl_trait)]
+
+type Foo<T> = impl std::fmt::Debug;
+
+fn foo() -> Foo<u32> {
+    5u32
+}
+```
+
+is not accepted. If it were accepted, one could create unsound situations like
+
+```compile_fail,E0792
+#![feature(type_alias_impl_trait)]
+
+type Foo<T> = impl Default;
+
+fn foo() -> Foo<u32> {
+    5u32
+}
+
+fn main() {
+    let x = Foo::<&'static mut String>::default();
+}
+```
+
+
+Instead you need to make the function generic:
+
+```
+#![feature(type_alias_impl_trait)]
+
+type Foo<T> = impl std::fmt::Debug;
+
+fn foo<U>() -> Foo<U> {
+    5u32
+}
+```
+
+This means that no matter the generic parameter to `foo`,
+the hidden type will always be `u32`.
+If you want to link the generic parameter to the hidden type,
+you can do that, too:
+
+
+```
+#![feature(type_alias_impl_trait)]
+
+use std::fmt::Debug;
+
+type Foo<T: Debug> = impl Debug;
+
+fn foo<U: Debug>() -> Foo<U> {
+    Vec::<U>::new()
+}
+```
diff --git a/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl b/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl
index e5cd1142b20..5f28839f136 100644
--- a/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/ast_passes.ftl
@@ -88,4 +88,5 @@ ast_passes_ty_alias_without_body =
 ast_passes_fn_without_body =
     free function without a body
     .suggestion = provide a definition for the function
-    .extern_block_suggestion = if you meant to declare an externally defined function, use an `extern` block
+
+ast_passes_extern_block_suggestion = if you meant to declare an externally defined function, use an `extern` block
diff --git a/compiler/rustc_error_messages/locales/en-US/borrowck.ftl b/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
index 2cd4733220e..9e4332c4283 100644
--- a/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/borrowck.ftl
@@ -120,3 +120,7 @@ borrowck_cannot_move_when_borrowed =
         [value] value
         *[other] {$value_place}
     } occurs here
+
+borrowck_opaque_type_non_generic_param =
+    expected generic {$kind} parameter, found `{$ty}`
+    .label = this generic parameter must be used with a generic {$kind} parameter
diff --git a/compiler/rustc_error_messages/locales/en-US/infer.ftl b/compiler/rustc_error_messages/locales/en-US/infer.ftl
index ae0091b0373..164d6d26d23 100644
--- a/compiler/rustc_error_messages/locales/en-US/infer.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/infer.ftl
@@ -193,7 +193,7 @@ infer_actual_impl_expl_expected_signature_any = {$leading_ellipsis ->
 infer_actual_impl_expl_expected_signature_some = {$leading_ellipsis ->
     [true] ...
     *[false] {""}
-}closure with signature `{$ty_or_sig}` must implement `{$trait_path}`, for some specific lifetime `'{lifetime_1}`...
+}closure with signature `{$ty_or_sig}` must implement `{$trait_path}`, for some specific lifetime `'{$lifetime_1}`...
 infer_actual_impl_expl_expected_signature_nothing = {$leading_ellipsis ->
     [true] ...
     *[false] {""}
@@ -209,7 +209,7 @@ infer_actual_impl_expl_expected_passive_any = {$leading_ellipsis ->
 infer_actual_impl_expl_expected_passive_some = {$leading_ellipsis ->
     [true] ...
     *[false] {""}
-}`{$trait_path}` would have to be implemented for the type `{$ty_or_sig}`, for some specific lifetime `'{lifetime_1}`...
+}`{$trait_path}` would have to be implemented for the type `{$ty_or_sig}`, for some specific lifetime `'{$lifetime_1}`...
 infer_actual_impl_expl_expected_passive_nothing = {$leading_ellipsis ->
     [true] ...
     *[false] {""}
@@ -225,7 +225,7 @@ infer_actual_impl_expl_expected_other_any = {$leading_ellipsis ->
 infer_actual_impl_expl_expected_other_some = {$leading_ellipsis ->
     [true] ...
     *[false] {""}
-}`{$ty_or_sig}` must implement `{$trait_path}`, for some specific lifetime `'{lifetime_1}`...
+}`{$ty_or_sig}` must implement `{$trait_path}`, for some specific lifetime `'{$lifetime_1}`...
 infer_actual_impl_expl_expected_other_nothing = {$leading_ellipsis ->
     [true] ...
     *[false] {""}
@@ -268,28 +268,28 @@ infer_but_calling_introduces = {$has_param_name ->
     [true] `{$param_name}`
     *[false] `fn` parameter
 } has {$lifetime_kind ->
-    [named] lifetime `{lifetime}`
-    *[anon] an anonymous lifetime `'_`
-} but calling `{assoc_item}` introduces an implicit `'static` lifetime requirement
+    [true] lifetime `{$lifetime}`
+    *[false] an anonymous lifetime `'_`
+} but calling `{$assoc_item}` introduces an implicit `'static` lifetime requirement
     .label1 = {$has_lifetime ->
-        [named] lifetime `{lifetime}`
-        *[anon] an anonymous lifetime `'_`
+        [true] lifetime `{$lifetime}`
+        *[false] an anonymous lifetime `'_`
     }
     .label2 = ...is used and required to live as long as `'static` here because of an implicit lifetime bound on the {$has_impl_path ->
-        [named] `impl` of `{$impl_path}`
-        *[anon] inherent `impl`
+        [true] `impl` of `{$impl_path}`
+        *[false] inherent `impl`
     }
 
 infer_but_needs_to_satisfy = {$has_param_name ->
     [true] `{$param_name}`
     *[false] `fn` parameter
 } has {$has_lifetime ->
-    [named] lifetime `{lifetime}`
-    *[anon] an anonymous lifetime `'_`
+    [true] lifetime `{$lifetime}`
+    *[false] an anonymous lifetime `'_`
 } but it needs to satisfy a `'static` lifetime requirement
     .influencer = this data with {$has_lifetime ->
-        [named] lifetime `{lifetime}`
-        *[anon] an anonymous lifetime `'_`
+        [true] lifetime `{$lifetime}`
+        *[false] an anonymous lifetime `'_`
     }...
     .require = {$spans_empty ->
         *[true] ...is used and required to live as long as `'static` here
@@ -302,8 +302,8 @@ infer_more_targeted = {$has_param_name ->
     [true] `{$param_name}`
     *[false] `fn` parameter
 } has {$has_lifetime ->
-    [named] lifetime `{lifetime}`
-    *[anon] an anonymous lifetime `'_`
+    [true] lifetime `{$lifetime}`
+    *[false] an anonymous lifetime `'_`
 } but calling `{$ident}` introduces an implicit `'static` lifetime requirement
 
 infer_ril_introduced_here = `'static` requirement introduced here
diff --git a/compiler/rustc_error_messages/locales/en-US/mir_build.ftl b/compiler/rustc_error_messages/locales/en-US/mir_build.ftl
index a082c0b61fa..224855fff8b 100644
--- a/compiler/rustc_error_messages/locales/en-US/mir_build.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/mir_build.ftl
@@ -364,3 +364,5 @@ mir_build_suggest_let_else = you might want to use `let else` to handle the {$co
         [one] variant that isn't
         *[other] variants that aren't
     } matched
+
+mir_build_suggest_attempted_int_lit = alternatively, you could prepend the pattern with an underscore to define a new named variable; identifiers cannot begin with digits
diff --git a/compiler/rustc_error_messages/locales/en-US/ty_utils.ftl b/compiler/rustc_error_messages/locales/en-US/ty_utils.ftl
index 1040ee1c97d..abe65a0e3fe 100644
--- a/compiler/rustc_error_messages/locales/en-US/ty_utils.ftl
+++ b/compiler/rustc_error_messages/locales/en-US/ty_utils.ftl
@@ -10,17 +10,17 @@ ty_utils_address_and_deref_not_supported = dereferencing or taking the address i
 
 ty_utils_array_not_supported = array construction is not supported in generic constants
 
-ty_utils_block_not_supported = blocks are not supported in generic constant
+ty_utils_block_not_supported = blocks are not supported in generic constants
 
-ty_utils_never_to_any_not_supported = converting nevers to any is not supported in generic constant
+ty_utils_never_to_any_not_supported = converting nevers to any is not supported in generic constants
 
 ty_utils_tuple_not_supported = tuple construction is not supported in generic constants
 
-ty_utils_index_not_supported = indexing is not supported in generic constant
+ty_utils_index_not_supported = indexing is not supported in generic constants
 
-ty_utils_field_not_supported = field access is not supported in generic constant
+ty_utils_field_not_supported = field access is not supported in generic constants
 
-ty_utils_const_block_not_supported = const blocks are not supported in generic constant
+ty_utils_const_block_not_supported = const blocks are not supported in generic constants
 
 ty_utils_adt_not_supported = struct/enum construction is not supported in generic constants
 
@@ -44,4 +44,4 @@ ty_utils_control_flow_not_supported = control flow is not supported in generic c
 
 ty_utils_inline_asm_not_supported = assembly is not supported in generic constants
 
-ty_utils_operation_not_supported = unsupported operation in generic constant
+ty_utils_operation_not_supported = unsupported operation in generic constants
diff --git a/compiler/rustc_expand/src/base.rs b/compiler/rustc_expand/src/base.rs
index ffde8480c02..951d5924678 100644
--- a/compiler/rustc_expand/src/base.rs
+++ b/compiler/rustc_expand/src/base.rs
@@ -63,21 +63,21 @@ pub enum Annotatable {
 
 impl Annotatable {
     pub fn span(&self) -> Span {
-        match *self {
-            Annotatable::Item(ref item) => item.span,
-            Annotatable::TraitItem(ref trait_item) => trait_item.span,
-            Annotatable::ImplItem(ref impl_item) => impl_item.span,
-            Annotatable::ForeignItem(ref foreign_item) => foreign_item.span,
-            Annotatable::Stmt(ref stmt) => stmt.span,
-            Annotatable::Expr(ref expr) => expr.span,
-            Annotatable::Arm(ref arm) => arm.span,
-            Annotatable::ExprField(ref field) => field.span,
-            Annotatable::PatField(ref fp) => fp.pat.span,
-            Annotatable::GenericParam(ref gp) => gp.ident.span,
-            Annotatable::Param(ref p) => p.span,
-            Annotatable::FieldDef(ref sf) => sf.span,
-            Annotatable::Variant(ref v) => v.span,
-            Annotatable::Crate(ref c) => c.spans.inner_span,
+        match self {
+            Annotatable::Item(item) => item.span,
+            Annotatable::TraitItem(trait_item) => trait_item.span,
+            Annotatable::ImplItem(impl_item) => impl_item.span,
+            Annotatable::ForeignItem(foreign_item) => foreign_item.span,
+            Annotatable::Stmt(stmt) => stmt.span,
+            Annotatable::Expr(expr) => expr.span,
+            Annotatable::Arm(arm) => arm.span,
+            Annotatable::ExprField(field) => field.span,
+            Annotatable::PatField(fp) => fp.pat.span,
+            Annotatable::GenericParam(gp) => gp.ident.span,
+            Annotatable::Param(p) => p.span,
+            Annotatable::FieldDef(sf) => sf.span,
+            Annotatable::Variant(v) => v.span,
+            Annotatable::Crate(c) => c.spans.inner_span,
         }
     }
 
diff --git a/compiler/rustc_expand/src/config.rs b/compiler/rustc_expand/src/config.rs
index f4c6f3386ad..1fcbdfd9be5 100644
--- a/compiler/rustc_expand/src/config.rs
+++ b/compiler/rustc_expand/src/config.rs
@@ -298,7 +298,7 @@ impl<'a> StripUnconfigured<'a> {
                     Some(AttrTokenTree::Delimited(sp, delim, inner))
                         .into_iter()
                 }
-                AttrTokenTree::Token(ref token, _) if let TokenKind::Interpolated(ref nt) = token.kind => {
+                AttrTokenTree::Token(ref token, _) if let TokenKind::Interpolated(nt) = &token.kind => {
                     panic!(
                         "Nonterminal should have been flattened at {:?}: {:?}",
                         token.span, nt
diff --git a/compiler/rustc_expand/src/expand.rs b/compiler/rustc_expand/src/expand.rs
index 5d47c1ed363..79d058d9c97 100644
--- a/compiler/rustc_expand/src/expand.rs
+++ b/compiler/rustc_expand/src/expand.rs
@@ -144,12 +144,12 @@ macro_rules! ast_fragments {
             }
 
             pub fn visit_with<'a, V: Visitor<'a>>(&'a self, visitor: &mut V) {
-                match *self {
-                    AstFragment::OptExpr(Some(ref expr)) => visitor.visit_expr(expr),
+                match self {
+                    AstFragment::OptExpr(Some(expr)) => visitor.visit_expr(expr),
                     AstFragment::OptExpr(None) => {}
-                    AstFragment::MethodReceiverExpr(ref expr) => visitor.visit_method_receiver_expr(expr),
-                    $($(AstFragment::$Kind(ref ast) => visitor.$visit_ast(ast),)?)*
-                    $($(AstFragment::$Kind(ref ast) => for ast_elt in &ast[..] {
+                    AstFragment::MethodReceiverExpr(expr) => visitor.visit_method_receiver_expr(expr),
+                    $($(AstFragment::$Kind(ast) => visitor.$visit_ast(ast),)?)*
+                    $($(AstFragment::$Kind(ast) => for ast_elt in &ast[..] {
                         visitor.$visit_ast_elt(ast_elt, $($args)*);
                     })?)*
                 }
@@ -592,7 +592,7 @@ impl<'a, 'b> MacroExpander<'a, 'b> {
                     let expn_id = invoc.expansion_data.id;
                     let parent_def = self.cx.resolver.invocation_parent(expn_id);
                     let span = match &mut invoc.kind {
-                        InvocationKind::Bang { ref mut span, .. } => span,
+                        InvocationKind::Bang { span, .. } => span,
                         InvocationKind::Attr { attr, .. } => &mut attr.span,
                         InvocationKind::Derive { path, .. } => &mut path.span,
                     };
@@ -945,8 +945,8 @@ pub fn ensure_complete_parse<'a>(
         let def_site_span = parser.token.span.with_ctxt(SyntaxContext::root());
 
         let semi_span = parser.sess.source_map().next_point(span);
-        let add_semicolon = match parser.sess.source_map().span_to_snippet(semi_span) {
-            Ok(ref snippet) if &snippet[..] != ";" && kind_name == "expression" => {
+        let add_semicolon = match &parser.sess.source_map().span_to_snippet(semi_span) {
+            Ok(snippet) if &snippet[..] != ";" && kind_name == "expression" => {
                 Some(span.shrink_to_hi())
             }
             _ => None,
diff --git a/compiler/rustc_expand/src/mbe/macro_check.rs b/compiler/rustc_expand/src/mbe/macro_check.rs
index 0b8847f827d..5be134f4e66 100644
--- a/compiler/rustc_expand/src/mbe/macro_check.rs
+++ b/compiler/rustc_expand/src/mbe/macro_check.rs
@@ -151,9 +151,9 @@ impl<'a, T> Iterator for &'a Stack<'a, T> {
 
     // Iterates from top to bottom of the stack.
     fn next(&mut self) -> Option<&'a T> {
-        match *self {
+        match self {
             Stack::Empty => None,
-            Stack::Push { ref top, ref prev } => {
+            Stack::Push { top, prev } => {
                 *self = prev;
                 Some(top)
             }
@@ -437,8 +437,8 @@ fn check_nested_occurrences(
                 // We check that the meta-variable is correctly used.
                 check_occurrences(sess, node_id, tt, macros, binders, ops, valid);
             }
-            (NestedMacroState::MacroRulesNotName, &TokenTree::Delimited(_, ref del))
-            | (NestedMacroState::MacroName, &TokenTree::Delimited(_, ref del))
+            (NestedMacroState::MacroRulesNotName, TokenTree::Delimited(_, del))
+            | (NestedMacroState::MacroName, TokenTree::Delimited(_, del))
                 if del.delim == Delimiter::Brace =>
             {
                 let macro_rules = state == NestedMacroState::MacroRulesNotName;
@@ -497,7 +497,7 @@ fn check_nested_occurrences(
                     valid,
                 );
             }
-            (_, ref tt) => {
+            (_, tt) => {
                 state = NestedMacroState::Empty;
                 check_occurrences(sess, node_id, tt, macros, binders, ops, valid);
             }
diff --git a/compiler/rustc_expand/src/mbe/macro_rules.rs b/compiler/rustc_expand/src/mbe/macro_rules.rs
index c0489f68633..4ebd75f0185 100644
--- a/compiler/rustc_expand/src/mbe/macro_rules.rs
+++ b/compiler/rustc_expand/src/mbe/macro_rules.rs
@@ -486,11 +486,11 @@ pub fn compile_declarative_macro(
     let mut valid = true;
 
     // Extract the arguments:
-    let lhses = match argument_map[&MacroRulesNormalizedIdent::new(lhs_nm)] {
-        MatchedSeq(ref s) => s
+    let lhses = match &argument_map[&MacroRulesNormalizedIdent::new(lhs_nm)] {
+        MatchedSeq(s) => s
             .iter()
             .map(|m| {
-                if let MatchedTokenTree(ref tt) = *m {
+                if let MatchedTokenTree(tt) = m {
                     let tt = mbe::quoted::parse(
                         TokenStream::new(vec![tt.clone()]),
                         true,
@@ -510,11 +510,11 @@ pub fn compile_declarative_macro(
         _ => sess.parse_sess.span_diagnostic.span_bug(def.span, "wrong-structured lhs"),
     };
 
-    let rhses = match argument_map[&MacroRulesNormalizedIdent::new(rhs_nm)] {
-        MatchedSeq(ref s) => s
+    let rhses = match &argument_map[&MacroRulesNormalizedIdent::new(rhs_nm)] {
+        MatchedSeq(s) => s
             .iter()
             .map(|m| {
-                if let MatchedTokenTree(ref tt) = *m {
+                if let MatchedTokenTree(tt) = m {
                     return mbe::quoted::parse(
                         TokenStream::new(vec![tt.clone()]),
                         false,
@@ -624,21 +624,21 @@ fn check_lhs_nt_follows(sess: &ParseSess, def: &ast::Item, lhs: &mbe::TokenTree)
 fn check_lhs_no_empty_seq(sess: &ParseSess, tts: &[mbe::TokenTree]) -> bool {
     use mbe::TokenTree;
     for tt in tts {
-        match *tt {
+        match tt {
             TokenTree::Token(..)
             | TokenTree::MetaVar(..)
             | TokenTree::MetaVarDecl(..)
             | TokenTree::MetaVarExpr(..) => (),
-            TokenTree::Delimited(_, ref del) => {
+            TokenTree::Delimited(_, del) => {
                 if !check_lhs_no_empty_seq(sess, &del.tts) {
                     return false;
                 }
             }
-            TokenTree::Sequence(span, ref seq) => {
+            TokenTree::Sequence(span, seq) => {
                 if seq.separator.is_none()
-                    && seq.tts.iter().all(|seq_tt| match *seq_tt {
+                    && seq.tts.iter().all(|seq_tt| match seq_tt {
                         TokenTree::MetaVarDecl(_, _, Some(NonterminalKind::Vis)) => true,
-                        TokenTree::Sequence(_, ref sub_seq) => {
+                        TokenTree::Sequence(_, sub_seq) => {
                             sub_seq.kleene.op == mbe::KleeneOp::ZeroOrMore
                                 || sub_seq.kleene.op == mbe::KleeneOp::ZeroOrOne
                         }
@@ -736,21 +736,21 @@ impl<'tt> FirstSets<'tt> {
         fn build_recur<'tt>(sets: &mut FirstSets<'tt>, tts: &'tt [TokenTree]) -> TokenSet<'tt> {
             let mut first = TokenSet::empty();
             for tt in tts.iter().rev() {
-                match *tt {
+                match tt {
                     TokenTree::Token(..)
                     | TokenTree::MetaVar(..)
                     | TokenTree::MetaVarDecl(..)
                     | TokenTree::MetaVarExpr(..) => {
                         first.replace_with(TtHandle::TtRef(tt));
                     }
-                    TokenTree::Delimited(span, ref delimited) => {
+                    TokenTree::Delimited(span, delimited) => {
                         build_recur(sets, &delimited.tts);
                         first.replace_with(TtHandle::from_token_kind(
                             token::OpenDelim(delimited.delim),
                             span.open,
                         ));
                     }
-                    TokenTree::Sequence(sp, ref seq_rep) => {
+                    TokenTree::Sequence(sp, seq_rep) => {
                         let subfirst = build_recur(sets, &seq_rep.tts);
 
                         match sets.first.entry(sp.entire()) {
@@ -804,7 +804,7 @@ impl<'tt> FirstSets<'tt> {
         let mut first = TokenSet::empty();
         for tt in tts.iter() {
             assert!(first.maybe_empty);
-            match *tt {
+            match tt {
                 TokenTree::Token(..)
                 | TokenTree::MetaVar(..)
                 | TokenTree::MetaVarDecl(..)
@@ -812,14 +812,14 @@ impl<'tt> FirstSets<'tt> {
                     first.add_one(TtHandle::TtRef(tt));
                     return first;
                 }
-                TokenTree::Delimited(span, ref delimited) => {
+                TokenTree::Delimited(span, delimited) => {
                     first.add_one(TtHandle::from_token_kind(
                         token::OpenDelim(delimited.delim),
                         span.open,
                     ));
                     return first;
                 }
-                TokenTree::Sequence(sp, ref seq_rep) => {
+                TokenTree::Sequence(sp, seq_rep) => {
                     let subfirst_owned;
                     let subfirst = match self.first.get(&sp.entire()) {
                         Some(Some(subfirst)) => subfirst,
@@ -1041,7 +1041,7 @@ fn check_matcher_core<'tt>(
 
         // First, update `last` so that it corresponds to the set
         // of NT tokens that might end the sequence `... token`.
-        match *token {
+        match token {
             TokenTree::Token(..)
             | TokenTree::MetaVar(..)
             | TokenTree::MetaVarDecl(..)
@@ -1057,7 +1057,7 @@ fn check_matcher_core<'tt>(
                     suffix_first = build_suffix_first();
                 }
             }
-            TokenTree::Delimited(span, ref d) => {
+            TokenTree::Delimited(span, d) => {
                 let my_suffix = TokenSet::singleton(TtHandle::from_token_kind(
                     token::CloseDelim(d.delim),
                     span.close,
@@ -1070,7 +1070,7 @@ fn check_matcher_core<'tt>(
                 // against SUFFIX
                 continue 'each_token;
             }
-            TokenTree::Sequence(_, ref seq_rep) => {
+            TokenTree::Sequence(_, seq_rep) => {
                 suffix_first = build_suffix_first();
                 // The trick here: when we check the interior, we want
                 // to include the separator (if any) as a potential
@@ -1372,8 +1372,8 @@ fn is_in_follow(tok: &mbe::TokenTree, kind: NonterminalKind) -> IsInFollow {
 }
 
 fn quoted_tt_to_string(tt: &mbe::TokenTree) -> String {
-    match *tt {
-        mbe::TokenTree::Token(ref token) => pprust::token_to_string(&token).into(),
+    match tt {
+        mbe::TokenTree::Token(token) => pprust::token_to_string(&token).into(),
         mbe::TokenTree::MetaVar(_, name) => format!("${}", name),
         mbe::TokenTree::MetaVarDecl(_, name, Some(kind)) => format!("${}:{}", name, kind),
         mbe::TokenTree::MetaVarDecl(_, name, None) => format!("${}:", name),
diff --git a/compiler/rustc_expand/src/mbe/transcribe.rs b/compiler/rustc_expand/src/mbe/transcribe.rs
index bec6d1a2df7..b79835be73a 100644
--- a/compiler/rustc_expand/src/mbe/transcribe.rs
+++ b/compiler/rustc_expand/src/mbe/transcribe.rs
@@ -47,8 +47,7 @@ impl<'a> Iterator for Frame<'a> {
 
     fn next(&mut self) -> Option<&'a mbe::TokenTree> {
         match self {
-            Frame::Delimited { tts, ref mut idx, .. }
-            | Frame::Sequence { tts, ref mut idx, .. } => {
+            Frame::Delimited { tts, idx, .. } | Frame::Sequence { tts, idx, .. } => {
                 let res = tts.get(*idx);
                 *idx += 1;
                 res
@@ -220,13 +219,13 @@ pub(super) fn transcribe<'a>(
                 let ident = MacroRulesNormalizedIdent::new(original_ident);
                 if let Some(cur_matched) = lookup_cur_matched(ident, interp, &repeats) {
                     match cur_matched {
-                        MatchedTokenTree(ref tt) => {
+                        MatchedTokenTree(tt) => {
                             // `tt`s are emitted into the output stream directly as "raw tokens",
                             // without wrapping them into groups.
                             let token = tt.clone();
                             result.push(token);
                         }
-                        MatchedNonterminal(ref nt) => {
+                        MatchedNonterminal(nt) => {
                             // Other variables are emitted into the output stream as groups with
                             // `Delimiter::Invisible` to maintain parsing priorities.
                             // `Interpolated` is currently used for such groups in rustc parser.
@@ -299,12 +298,11 @@ fn lookup_cur_matched<'a>(
     interpolations: &'a FxHashMap<MacroRulesNormalizedIdent, NamedMatch>,
     repeats: &[(usize, usize)],
 ) -> Option<&'a NamedMatch> {
-    interpolations.get(&ident).map(|matched| {
-        let mut matched = matched;
+    interpolations.get(&ident).map(|mut matched| {
         for &(idx, _) in repeats {
             match matched {
                 MatchedTokenTree(_) | MatchedNonterminal(_) => break,
-                MatchedSeq(ref ads) => matched = ads.get(idx).unwrap(),
+                MatchedSeq(ads) => matched = ads.get(idx).unwrap(),
             }
         }
 
@@ -339,7 +337,7 @@ impl LockstepIterSize {
         match self {
             LockstepIterSize::Unconstrained => other,
             LockstepIterSize::Contradiction(_) => self,
-            LockstepIterSize::Constraint(l_len, ref l_id) => match other {
+            LockstepIterSize::Constraint(l_len, l_id) => match other {
                 LockstepIterSize::Unconstrained => self,
                 LockstepIterSize::Contradiction(_) => other,
                 LockstepIterSize::Constraint(r_len, _) if l_len == r_len => self,
@@ -378,33 +376,33 @@ fn lockstep_iter_size(
     repeats: &[(usize, usize)],
 ) -> LockstepIterSize {
     use mbe::TokenTree;
-    match *tree {
-        TokenTree::Delimited(_, ref delimited) => {
+    match tree {
+        TokenTree::Delimited(_, delimited) => {
             delimited.tts.iter().fold(LockstepIterSize::Unconstrained, |size, tt| {
                 size.with(lockstep_iter_size(tt, interpolations, repeats))
             })
         }
-        TokenTree::Sequence(_, ref seq) => {
+        TokenTree::Sequence(_, seq) => {
             seq.tts.iter().fold(LockstepIterSize::Unconstrained, |size, tt| {
                 size.with(lockstep_iter_size(tt, interpolations, repeats))
             })
         }
         TokenTree::MetaVar(_, name) | TokenTree::MetaVarDecl(_, name, _) => {
-            let name = MacroRulesNormalizedIdent::new(name);
+            let name = MacroRulesNormalizedIdent::new(*name);
             match lookup_cur_matched(name, interpolations, repeats) {
                 Some(matched) => match matched {
                     MatchedTokenTree(_) | MatchedNonterminal(_) => LockstepIterSize::Unconstrained,
-                    MatchedSeq(ref ads) => LockstepIterSize::Constraint(ads.len(), name),
+                    MatchedSeq(ads) => LockstepIterSize::Constraint(ads.len(), name),
                 },
                 _ => LockstepIterSize::Unconstrained,
             }
         }
-        TokenTree::MetaVarExpr(_, ref expr) => {
+        TokenTree::MetaVarExpr(_, expr) => {
             let default_rslt = LockstepIterSize::Unconstrained;
             let Some(ident) = expr.ident() else { return default_rslt; };
             let name = MacroRulesNormalizedIdent::new(ident);
             match lookup_cur_matched(name, interpolations, repeats) {
-                Some(MatchedSeq(ref ads)) => {
+                Some(MatchedSeq(ads)) => {
                     default_rslt.with(LockstepIterSize::Constraint(ads.len(), name))
                 }
                 _ => default_rslt,
@@ -449,7 +447,7 @@ fn count_repetitions<'a>(
                     Some(_) => Err(out_of_bounds_err(cx, declared_lhs_depth, sp.entire(), "count")),
                 }
             }
-            MatchedSeq(ref named_matches) => {
+            MatchedSeq(named_matches) => {
                 let new_declared_lhs_depth = declared_lhs_depth + 1;
                 match depth_opt {
                     None => named_matches
@@ -472,7 +470,7 @@ fn count_repetitions<'a>(
     // before we start counting. `matched` contains the various levels of the
     // tree as we descend, and its final value is the subtree we are currently at.
     for &(idx, _) in repeats {
-        if let MatchedSeq(ref ads) = matched {
+        if let MatchedSeq(ads) = matched {
             matched = &ads[idx];
         }
     }
diff --git a/compiler/rustc_expand/src/parse/tests.rs b/compiler/rustc_expand/src/parse/tests.rs
index e49f112bf20..0726d922c84 100644
--- a/compiler/rustc_expand/src/parse/tests.rs
+++ b/compiler/rustc_expand/src/parse/tests.rs
@@ -176,9 +176,9 @@ fn get_spans_of_pat_idents(src: &str) -> Vec<Span> {
     }
     impl<'a> visit::Visitor<'a> for PatIdentVisitor {
         fn visit_pat(&mut self, p: &'a ast::Pat) {
-            match p.kind {
-                PatKind::Ident(_, ref ident, _) => {
-                    self.spans.push(ident.span.clone());
+            match &p.kind {
+                PatKind::Ident(_, ident, _) => {
+                    self.spans.push(ident.span);
                 }
                 _ => {
                     visit::walk_pat(self, p);
@@ -290,10 +290,8 @@ fn ttdelim_span() {
         )
         .unwrap();
 
-        let tts: Vec<_> = match expr.kind {
-            ast::ExprKind::MacCall(ref mac) => mac.args.tokens.clone().into_trees().collect(),
-            _ => panic!("not a macro"),
-        };
+        let ast::ExprKind::MacCall(mac) = &expr.kind else { panic!("not a macro") };
+        let tts: Vec<_> = mac.args.tokens.clone().into_trees().collect();
 
         let span = tts.iter().rev().next().unwrap().span();
 
@@ -318,11 +316,8 @@ fn out_of_line_mod() {
         .unwrap()
         .unwrap();
 
-        if let ast::ItemKind::Mod(_, ref mod_kind) = item.kind {
-            assert!(matches!(mod_kind, ast::ModKind::Loaded(items, ..) if items.len() == 2));
-        } else {
-            panic!();
-        }
+        let ast::ItemKind::Mod(_, mod_kind) = &item.kind else { panic!() };
+        assert!(matches!(mod_kind, ast::ModKind::Loaded(items, ..) if items.len() == 2));
     });
 }
 
diff --git a/compiler/rustc_expand/src/proc_macro_server.rs b/compiler/rustc_expand/src/proc_macro_server.rs
index af38077b080..341ae18541b 100644
--- a/compiler/rustc_expand/src/proc_macro_server.rs
+++ b/compiler/rustc_expand/src/proc_macro_server.rs
@@ -597,8 +597,8 @@ impl server::SourceFile for Rustc<'_, '_> {
     }
 
     fn path(&mut self, file: &Self::SourceFile) -> String {
-        match file.name {
-            FileName::Real(ref name) => name
+        match &file.name {
+            FileName::Real(name) => name
                 .local_path()
                 .expect("attempting to get a file path in an imported file in `proc_macro::SourceFile::path`")
                 .to_str()
diff --git a/compiler/rustc_hir/src/hir.rs b/compiler/rustc_hir/src/hir.rs
index 56f0e0b3e7d..d6566860f81 100644
--- a/compiler/rustc_hir/src/hir.rs
+++ b/compiler/rustc_hir/src/hir.rs
@@ -1787,6 +1787,14 @@ impl Expr<'_> {
         expr
     }
 
+    pub fn peel_borrows(&self) -> &Self {
+        let mut expr = self;
+        while let ExprKind::AddrOf(.., inner) = &expr.kind {
+            expr = inner;
+        }
+        expr
+    }
+
     pub fn can_have_side_effects(&self) -> bool {
         match self.peel_drop_temps().kind {
             ExprKind::Path(_) | ExprKind::Lit(_) => false,
diff --git a/compiler/rustc_hir/src/lang_items.rs b/compiler/rustc_hir/src/lang_items.rs
index 3474fab34f0..54fa5702fbc 100644
--- a/compiler/rustc_hir/src/lang_items.rs
+++ b/compiler/rustc_hir/src/lang_items.rs
@@ -291,6 +291,7 @@ language_item_table! {
     IdentityFuture,          sym::identity_future,     identity_future_fn,         Target::Fn,             GenericRequirement::None;
     GetContext,              sym::get_context,         get_context_fn,             Target::Fn,             GenericRequirement::None;
 
+    Context,                 sym::Context,             context,                    Target::Struct,         GenericRequirement::None;
     FuturePoll,              sym::poll,                future_poll_fn,             Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
 
     FromFrom,                sym::from,                from_fn,                    Target::Method(MethodKind::Trait { body: false }), GenericRequirement::None;
diff --git a/compiler/rustc_hir_analysis/src/astconv/mod.rs b/compiler/rustc_hir_analysis/src/astconv/mod.rs
index 9031c04849d..6435b05cef8 100644
--- a/compiler/rustc_hir_analysis/src/astconv/mod.rs
+++ b/compiler/rustc_hir_analysis/src/astconv/mod.rs
@@ -569,17 +569,17 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
             .bindings
             .iter()
             .map(|binding| {
-                let kind = match binding.kind {
-                    hir::TypeBindingKind::Equality { ref term } => match term {
-                        hir::Term::Ty(ref ty) => {
+                let kind = match &binding.kind {
+                    hir::TypeBindingKind::Equality { term } => match term {
+                        hir::Term::Ty(ty) => {
                             ConvertedBindingKind::Equality(self.ast_ty_to_ty(ty).into())
                         }
-                        hir::Term::Const(ref c) => {
+                        hir::Term::Const(c) => {
                             let c = Const::from_anon_const(self.tcx(), c.def_id);
                             ConvertedBindingKind::Equality(c.into())
                         }
                     },
-                    hir::TypeBindingKind::Constraint { ref bounds } => {
+                    hir::TypeBindingKind::Constraint { bounds } => {
                         ConvertedBindingKind::Constraint(bounds)
                     }
                 };
@@ -1928,7 +1928,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     ) -> Result<(Ty<'tcx>, DefKind, DefId), ErrorGuaranteed> {
         let tcx = self.tcx();
         let assoc_ident = assoc_segment.ident;
-        let qself_res = if let hir::TyKind::Path(hir::QPath::Resolved(_, ref path)) = qself.kind {
+        let qself_res = if let hir::TyKind::Path(hir::QPath::Resolved(_, path)) = &qself.kind {
             path.res
         } else {
             Res::Err
@@ -1971,8 +1971,8 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                                 return;
                             };
                             let (qself_sugg_span, is_self) = if let hir::TyKind::Path(
-                                hir::QPath::Resolved(_, ref path)
-                            ) = qself.kind {
+                                hir::QPath::Resolved(_, path)
+                            ) = &qself.kind {
                                 // If the path segment already has type params, we want to overwrite
                                 // them.
                                 match &path.segments[..] {
@@ -2602,7 +2602,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
         match path.res {
             Res::Def(DefKind::OpaqueTy | DefKind::ImplTraitPlaceholder, did) => {
                 // Check for desugared `impl Trait`.
-                assert!(ty::is_impl_trait_defn(tcx, did).is_none());
+                assert!(tcx.is_type_alias_impl_trait(did));
                 let item_segment = path.segments.split_last().unwrap();
                 self.prohibit_generics(item_segment.1.iter(), |err| {
                     err.note("`impl Trait` types can't have type parameters");
@@ -2760,7 +2760,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                         "generic `Self` types are currently not permitted in anonymous constants",
                     );
                     if let Some(hir::Node::Item(&hir::Item {
-                        kind: hir::ItemKind::Impl(ref impl_),
+                        kind: hir::ItemKind::Impl(impl_),
                         ..
                     })) = tcx.hir().get_if_local(def_id)
                     {
@@ -2843,12 +2843,12 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
     fn ast_ty_to_ty_inner(&self, ast_ty: &hir::Ty<'_>, borrowed: bool, in_path: bool) -> Ty<'tcx> {
         let tcx = self.tcx();
 
-        let result_ty = match ast_ty.kind {
-            hir::TyKind::Slice(ref ty) => tcx.mk_slice(self.ast_ty_to_ty(ty)),
-            hir::TyKind::Ptr(ref mt) => {
+        let result_ty = match &ast_ty.kind {
+            hir::TyKind::Slice(ty) => tcx.mk_slice(self.ast_ty_to_ty(ty)),
+            hir::TyKind::Ptr(mt) => {
                 tcx.mk_ptr(ty::TypeAndMut { ty: self.ast_ty_to_ty(mt.ty), mutbl: mt.mutbl })
             }
-            hir::TyKind::Ref(ref region, ref mt) => {
+            hir::TyKind::Ref(region, mt) => {
                 let r = self.ast_region_to_region(region, None);
                 debug!(?r);
                 let t = self.ast_ty_to_ty_inner(mt.ty, true, false);
@@ -2868,7 +2868,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     Some(ast_ty),
                 ))
             }
-            hir::TyKind::TraitObject(bounds, ref lifetime, repr) => {
+            hir::TyKind::TraitObject(bounds, lifetime, repr) => {
                 self.maybe_lint_bare_trait(ast_ty, in_path);
                 let repr = match repr {
                     TraitObjectSyntax::Dyn | TraitObjectSyntax::None => ty::Dyn,
@@ -2876,12 +2876,12 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 };
                 self.conv_object_ty_poly_trait_ref(ast_ty.span, bounds, lifetime, borrowed, repr)
             }
-            hir::TyKind::Path(hir::QPath::Resolved(ref maybe_qself, ref path)) => {
+            hir::TyKind::Path(hir::QPath::Resolved(maybe_qself, path)) => {
                 debug!(?maybe_qself, ?path);
                 let opt_self_ty = maybe_qself.as_ref().map(|qself| self.ast_ty_to_ty(qself));
                 self.res_to_ty(opt_self_ty, path, false)
             }
-            hir::TyKind::OpaqueDef(item_id, lifetimes, in_trait) => {
+            &hir::TyKind::OpaqueDef(item_id, lifetimes, in_trait) => {
                 let opaque_ty = tcx.hir().item(item_id);
                 let def_id = item_id.owner_id.to_def_id();
 
@@ -2892,14 +2892,14 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                     ref i => bug!("`impl Trait` pointed to non-opaque type?? {:#?}", i),
                 }
             }
-            hir::TyKind::Path(hir::QPath::TypeRelative(ref qself, ref segment)) => {
+            hir::TyKind::Path(hir::QPath::TypeRelative(qself, segment)) => {
                 debug!(?qself, ?segment);
                 let ty = self.ast_ty_to_ty_inner(qself, false, true);
                 self.associated_path_to_ty(ast_ty.hir_id, ast_ty.span, ty, qself, segment, false)
                     .map(|(ty, _, _)| ty)
                     .unwrap_or_else(|_| tcx.ty_error())
             }
-            hir::TyKind::Path(hir::QPath::LangItem(lang_item, span, _)) => {
+            &hir::TyKind::Path(hir::QPath::LangItem(lang_item, span, _)) => {
                 let def_id = tcx.require_lang_item(lang_item, Some(span));
                 let (substs, _) = self.create_substs_for_ast_path(
                     span,
@@ -2913,7 +2913,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
                 );
                 EarlyBinder(tcx.at(span).type_of(def_id)).subst(tcx, substs)
             }
-            hir::TyKind::Array(ref ty, ref length) => {
+            hir::TyKind::Array(ty, length) => {
                 let length = match length {
                     &hir::ArrayLen::Infer(_, span) => self.ct_infer(tcx.types.usize, None, span),
                     hir::ArrayLen::Body(constant) => {
@@ -2923,7 +2923,7 @@ impl<'o, 'tcx> dyn AstConv<'tcx> + 'o {
 
                 tcx.mk_ty(ty::Array(self.ast_ty_to_ty(ty), length))
             }
-            hir::TyKind::Typeof(ref e) => {
+            hir::TyKind::Typeof(e) => {
                 let ty_erased = tcx.type_of(e.def_id);
                 let ty = tcx.fold_regions(ty_erased, |r, _| {
                     if r.is_erased() { tcx.lifetimes.re_static } else { r }
diff --git a/compiler/rustc_hir_analysis/src/check/check.rs b/compiler/rustc_hir_analysis/src/check/check.rs
index e58669433e2..abc1c2d7b8d 100644
--- a/compiler/rustc_hir_analysis/src/check/check.rs
+++ b/compiler/rustc_hir_analysis/src/check/check.rs
@@ -267,7 +267,7 @@ pub(super) fn check_opaque_for_inheriting_lifetimes(
         fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
             debug!(?t, "root_visit_ty");
             if t == self.opaque_identity_ty {
-                ControlFlow::CONTINUE
+                ControlFlow::Continue(())
             } else {
                 t.visit_with(&mut ConstrainOpaqueTypeRegionVisitor {
                     tcx: self.tcx,
@@ -282,7 +282,7 @@ pub(super) fn check_opaque_for_inheriting_lifetimes(
                 if self.references_parent_regions {
                     ControlFlow::Break(t)
                 } else {
-                    ControlFlow::CONTINUE
+                    ControlFlow::Continue(())
                 }
             }
         }
@@ -531,9 +531,7 @@ fn check_item_type(tcx: TyCtxt<'_>, id: hir::ItemId) {
         DefKind::Fn => {} // entirely within check_item_body
         DefKind::Impl => {
             let it = tcx.hir().item(id);
-            let hir::ItemKind::Impl(ref impl_) = it.kind else {
-                return;
-            };
+            let hir::ItemKind::Impl(impl_) = it.kind else { return };
             debug!("ItemKind::Impl {} with id {:?}", it.ident, it.owner_id);
             if let Some(impl_trait_ref) = tcx.impl_trait_ref(it.owner_id) {
                 check_impl_items_against_trait(
@@ -548,15 +546,15 @@ fn check_item_type(tcx: TyCtxt<'_>, id: hir::ItemId) {
         }
         DefKind::Trait => {
             let it = tcx.hir().item(id);
-            let hir::ItemKind::Trait(_, _, _, _, ref items) = it.kind else {
+            let hir::ItemKind::Trait(_, _, _, _, items) = it.kind else {
                 return;
             };
             check_on_unimplemented(tcx, it);
 
             for item in items.iter() {
                 let item = tcx.hir().trait_item(item.id);
-                match item.kind {
-                    hir::TraitItemKind::Fn(ref sig, _) => {
+                match &item.kind {
+                    hir::TraitItemKind::Fn(sig, _) => {
                         let abi = sig.header.abi;
                         fn_maybe_err(tcx, item.ident.span, abi);
                     }
@@ -652,8 +650,8 @@ fn check_item_type(tcx: TyCtxt<'_>, id: hir::ItemId) {
                     }
 
                     let item = tcx.hir().foreign_item(item.id);
-                    match item.kind {
-                        hir::ForeignItemKind::Fn(ref fn_decl, _, _) => {
+                    match &item.kind {
+                        hir::ForeignItemKind::Fn(fn_decl, _, _) => {
                             require_c_abi_if_c_variadic(tcx, fn_decl, abi, item.span);
                         }
                         hir::ForeignItemKind::Static(..) => {
@@ -1393,11 +1391,15 @@ fn async_opaque_type_cycle_error(tcx: TyCtxt<'_>, span: Span) -> ErrorGuaranteed
 ///
 /// If all the return expressions evaluate to `!`, then we explain that the error will go away
 /// after changing it. This can happen when a user uses `panic!()` or similar as a placeholder.
-fn opaque_type_cycle_error(tcx: TyCtxt<'_>, def_id: LocalDefId, span: Span) -> ErrorGuaranteed {
+fn opaque_type_cycle_error(
+    tcx: TyCtxt<'_>,
+    opaque_def_id: LocalDefId,
+    span: Span,
+) -> ErrorGuaranteed {
     let mut err = struct_span_err!(tcx.sess, span, E0720, "cannot resolve opaque type");
 
     let mut label = false;
-    if let Some((def_id, visitor)) = get_owner_return_paths(tcx, def_id) {
+    if let Some((def_id, visitor)) = get_owner_return_paths(tcx, opaque_def_id) {
         let typeck_results = tcx.typeck(def_id);
         if visitor
             .returns
@@ -1433,21 +1435,30 @@ fn opaque_type_cycle_error(tcx: TyCtxt<'_>, def_id: LocalDefId, span: Span) -> E
                 .filter_map(|e| typeck_results.node_type_opt(e.hir_id).map(|t| (e.span, t)))
                 .filter(|(_, ty)| !matches!(ty.kind(), ty::Never))
             {
-                struct OpaqueTypeCollector(Vec<DefId>);
+                #[derive(Default)]
+                struct OpaqueTypeCollector {
+                    opaques: Vec<DefId>,
+                    closures: Vec<DefId>,
+                }
                 impl<'tcx> ty::visit::TypeVisitor<'tcx> for OpaqueTypeCollector {
                     fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
                         match *t.kind() {
                             ty::Alias(ty::Opaque, ty::AliasTy { def_id: def, .. }) => {
-                                self.0.push(def);
-                                ControlFlow::CONTINUE
+                                self.opaques.push(def);
+                                ControlFlow::Continue(())
+                            }
+                            ty::Closure(def_id, ..) | ty::Generator(def_id, ..) => {
+                                self.closures.push(def_id);
+                                t.super_visit_with(self)
                             }
                             _ => t.super_visit_with(self),
                         }
                     }
                 }
-                let mut visitor = OpaqueTypeCollector(vec![]);
+
+                let mut visitor = OpaqueTypeCollector::default();
                 ty.visit_with(&mut visitor);
-                for def_id in visitor.0 {
+                for def_id in visitor.opaques {
                     let ty_span = tcx.def_span(def_id);
                     if !seen.contains(&ty_span) {
                         err.span_label(ty_span, &format!("returning this opaque type `{ty}`"));
@@ -1455,6 +1466,40 @@ fn opaque_type_cycle_error(tcx: TyCtxt<'_>, def_id: LocalDefId, span: Span) -> E
                     }
                     err.span_label(sp, &format!("returning here with type `{ty}`"));
                 }
+
+                for closure_def_id in visitor.closures {
+                    let Some(closure_local_did) = closure_def_id.as_local() else { continue; };
+                    let typeck_results = tcx.typeck(closure_local_did);
+
+                    let mut label_match = |ty: Ty<'_>, span| {
+                        for arg in ty.walk() {
+                            if let ty::GenericArgKind::Type(ty) = arg.unpack()
+                                && let ty::Alias(ty::Opaque, ty::AliasTy { def_id: captured_def_id, .. }) = *ty.kind()
+                                && captured_def_id == opaque_def_id.to_def_id()
+                            {
+                                err.span_label(
+                                    span,
+                                    format!(
+                                        "{} captures itself here",
+                                        tcx.def_kind(closure_def_id).descr(closure_def_id)
+                                    ),
+                                );
+                            }
+                        }
+                    };
+
+                    // Label any closure upvars that capture the opaque
+                    for capture in typeck_results.closure_min_captures_flattened(closure_local_did)
+                    {
+                        label_match(capture.place.ty(), capture.get_path_span(tcx));
+                    }
+                    // Label any generator locals that capture the opaque
+                    for interior_ty in
+                        typeck_results.generator_interior_types.as_ref().skip_binder()
+                    {
+                        label_match(interior_ty.ty, interior_ty.span);
+                    }
+                }
             }
         }
     }
diff --git a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
index 609c8377f68..cfebcceef3c 100644
--- a/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
+++ b/compiler/rustc_hir_analysis/src/check/compare_impl_item.rs
@@ -47,42 +47,22 @@ pub(super) fn compare_impl_method<'tcx>(
 
     let impl_m_span = tcx.def_span(impl_m.def_id);
 
-    if let Err(_) = compare_self_type(tcx, impl_m, impl_m_span, trait_m, impl_trait_ref) {
-        return;
-    }
-
-    if let Err(_) = compare_number_of_generics(tcx, impl_m, trait_m, trait_item_span, false) {
-        return;
-    }
-
-    if let Err(_) = compare_generic_param_kinds(tcx, impl_m, trait_m, false) {
-        return;
-    }
-
-    if let Err(_) =
-        compare_number_of_method_arguments(tcx, impl_m, impl_m_span, trait_m, trait_item_span)
-    {
-        return;
-    }
-
-    if let Err(_) = compare_synthetic_generics(tcx, impl_m, trait_m) {
-        return;
-    }
-
-    if let Err(_) = compare_asyncness(tcx, impl_m, impl_m_span, trait_m, trait_item_span) {
-        return;
-    }
-
-    if let Err(_) = compare_method_predicate_entailment(
-        tcx,
-        impl_m,
-        impl_m_span,
-        trait_m,
-        impl_trait_ref,
-        CheckImpliedWfMode::Check,
-    ) {
-        return;
-    }
+    let _: Result<_, ErrorGuaranteed> = try {
+        compare_self_type(tcx, impl_m, impl_m_span, trait_m, impl_trait_ref)?;
+        compare_number_of_generics(tcx, impl_m, trait_m, trait_item_span, false)?;
+        compare_generic_param_kinds(tcx, impl_m, trait_m, false)?;
+        compare_number_of_method_arguments(tcx, impl_m, impl_m_span, trait_m, trait_item_span)?;
+        compare_synthetic_generics(tcx, impl_m, trait_m)?;
+        compare_asyncness(tcx, impl_m, impl_m_span, trait_m, trait_item_span)?;
+        compare_method_predicate_entailment(
+            tcx,
+            impl_m,
+            impl_m_span,
+            trait_m,
+            impl_trait_ref,
+            CheckImpliedWfMode::Check,
+        )?;
+    };
 }
 
 /// This function is best explained by example. Consider a trait:
@@ -209,9 +189,11 @@ fn compare_method_predicate_entailment<'tcx>(
     //
     // We then register the obligations from the impl_m and check to see
     // if all constraints hold.
-    hybrid_preds
-        .predicates
-        .extend(trait_m_predicates.instantiate_own(tcx, trait_to_placeholder_substs).predicates);
+    hybrid_preds.predicates.extend(
+        trait_m_predicates
+            .instantiate_own(tcx, trait_to_placeholder_substs)
+            .map(|(predicate, _)| predicate),
+    );
 
     // Construct trait parameter environment and then shift it into the placeholder viewpoint.
     // The key step here is to update the caller_bounds's predicates to be
@@ -230,7 +212,7 @@ fn compare_method_predicate_entailment<'tcx>(
     debug!("compare_impl_method: caller_bounds={:?}", param_env.caller_bounds());
 
     let impl_m_own_bounds = impl_m_predicates.instantiate_own(tcx, impl_to_placeholder_substs);
-    for (predicate, span) in iter::zip(impl_m_own_bounds.predicates, impl_m_own_bounds.spans) {
+    for (predicate, span) in impl_m_own_bounds {
         let normalize_cause = traits::ObligationCause::misc(span, impl_m_hir_id);
         let predicate = ocx.normalize(&normalize_cause, param_env, predicate);
 
@@ -934,16 +916,14 @@ fn report_trait_method_mismatch<'tcx>(
             // When the `impl` receiver is an arbitrary self type, like `self: Box<Self>`, the
             // span points only at the type `Box<Self`>, but we want to cover the whole
             // argument pattern and type.
-            let span = match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind {
-                ImplItemKind::Fn(ref sig, body) => tcx
-                    .hir()
-                    .body_param_names(body)
-                    .zip(sig.decl.inputs.iter())
-                    .map(|(param, ty)| param.span.to(ty.span))
-                    .next()
-                    .unwrap_or(impl_err_span),
-                _ => bug!("{:?} is not a method", impl_m),
-            };
+            let ImplItemKind::Fn(ref sig, body) = tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind else { bug!("{impl_m:?} is not a method") };
+            let span = tcx
+                .hir()
+                .body_param_names(body)
+                .zip(sig.decl.inputs.iter())
+                .map(|(param, ty)| param.span.to(ty.span))
+                .next()
+                .unwrap_or(impl_err_span);
 
             diag.span_suggestion(
                 span,
@@ -956,22 +936,21 @@ fn report_trait_method_mismatch<'tcx>(
             if trait_sig.inputs().len() == *i {
                 // Suggestion to change output type. We do not suggest in `async` functions
                 // to avoid complex logic or incorrect output.
-                match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind {
-                    ImplItemKind::Fn(ref sig, _) if !sig.header.asyncness.is_async() => {
-                        let msg = "change the output type to match the trait";
-                        let ap = Applicability::MachineApplicable;
-                        match sig.decl.output {
-                            hir::FnRetTy::DefaultReturn(sp) => {
-                                let sugg = format!("-> {} ", trait_sig.output());
-                                diag.span_suggestion_verbose(sp, msg, sugg, ap);
-                            }
-                            hir::FnRetTy::Return(hir_ty) => {
-                                let sugg = trait_sig.output();
-                                diag.span_suggestion(hir_ty.span, msg, sugg, ap);
-                            }
-                        };
-                    }
-                    _ => {}
+                if let ImplItemKind::Fn(sig, _) = &tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind
+                    && !sig.header.asyncness.is_async()
+                {
+                    let msg = "change the output type to match the trait";
+                    let ap = Applicability::MachineApplicable;
+                    match sig.decl.output {
+                        hir::FnRetTy::DefaultReturn(sp) => {
+                            let sugg = format!("-> {} ", trait_sig.output());
+                            diag.span_suggestion_verbose(sp, msg, sugg, ap);
+                        }
+                        hir::FnRetTy::Return(hir_ty) => {
+                            let sugg = trait_sig.output();
+                            diag.span_suggestion(hir_ty.span, msg, sugg, ap);
+                        }
+                    };
                 };
             } else if let Some(trait_ty) = trait_sig.inputs().get(*i) {
                 diag.span_suggestion(
@@ -1098,25 +1077,18 @@ fn extract_spans_for_error_reporting<'tcx>(
     trait_m: &ty::AssocItem,
 ) -> (Span, Option<Span>) {
     let tcx = infcx.tcx;
-    let mut impl_args = match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind {
-        ImplItemKind::Fn(ref sig, _) => {
-            sig.decl.inputs.iter().map(|t| t.span).chain(iter::once(sig.decl.output.span()))
-        }
-        _ => bug!("{:?} is not a method", impl_m),
+    let mut impl_args = {
+        let ImplItemKind::Fn(sig, _) = &tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind else { bug!("{:?} is not a method", impl_m) };
+        sig.decl.inputs.iter().map(|t| t.span).chain(iter::once(sig.decl.output.span()))
     };
-    let trait_args =
-        trait_m.def_id.as_local().map(|def_id| match tcx.hir().expect_trait_item(def_id).kind {
-            TraitItemKind::Fn(ref sig, _) => {
-                sig.decl.inputs.iter().map(|t| t.span).chain(iter::once(sig.decl.output.span()))
-            }
-            _ => bug!("{:?} is not a TraitItemKind::Fn", trait_m),
-        });
+
+    let trait_args = trait_m.def_id.as_local().map(|def_id| {
+        let TraitItemKind::Fn(sig, _) = &tcx.hir().expect_trait_item(def_id).kind else { bug!("{:?} is not a TraitItemKind::Fn", trait_m) };
+        sig.decl.inputs.iter().map(|t| t.span).chain(iter::once(sig.decl.output.span()))
+    });
 
     match terr {
-        TypeError::ArgumentMutability(i) => {
-            (impl_args.nth(i).unwrap(), trait_args.and_then(|mut args| args.nth(i)))
-        }
-        TypeError::ArgumentSorts(ExpectedFound { .. }, i) => {
+        TypeError::ArgumentMutability(i) | TypeError::ArgumentSorts(ExpectedFound { .. }, i) => {
             (impl_args.nth(i).unwrap(), trait_args.and_then(|mut args| args.nth(i)))
         }
         _ => (cause.span(), tcx.hir().span_if_local(trait_m.def_id)),
@@ -1176,8 +1148,7 @@ fn compare_self_type<'tcx>(
             } else {
                 err.note_trait_signature(trait_m.name, trait_m.signature(tcx));
             }
-            let reported = err.emit();
-            return Err(reported);
+            return Err(err.emit());
         }
 
         (true, false) => {
@@ -1196,8 +1167,8 @@ fn compare_self_type<'tcx>(
             } else {
                 err.note_trait_signature(trait_m.name, trait_m.signature(tcx));
             }
-            let reported = err.emit();
-            return Err(reported);
+
+            return Err(err.emit());
         }
     }
 
@@ -1379,41 +1350,39 @@ fn compare_number_of_method_arguments<'tcx>(
     let trait_m_fty = tcx.fn_sig(trait_m.def_id);
     let trait_number_args = trait_m_fty.inputs().skip_binder().len();
     let impl_number_args = impl_m_fty.inputs().skip_binder().len();
+
     if trait_number_args != impl_number_args {
-        let trait_span = if let Some(def_id) = trait_m.def_id.as_local() {
-            match tcx.hir().expect_trait_item(def_id).kind {
-                TraitItemKind::Fn(ref trait_m_sig, _) => {
-                    let pos = if trait_number_args > 0 { trait_number_args - 1 } else { 0 };
-                    if let Some(arg) = trait_m_sig.decl.inputs.get(pos) {
-                        Some(if pos == 0 {
-                            arg.span
-                        } else {
-                            arg.span.with_lo(trait_m_sig.decl.inputs[0].span.lo())
-                        })
-                    } else {
-                        trait_item_span
-                    }
-                }
-                _ => bug!("{:?} is not a method", impl_m),
-            }
-        } else {
-            trait_item_span
-        };
-        let impl_span = match tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind {
-            ImplItemKind::Fn(ref impl_m_sig, _) => {
-                let pos = if impl_number_args > 0 { impl_number_args - 1 } else { 0 };
-                if let Some(arg) = impl_m_sig.decl.inputs.get(pos) {
+        let trait_span = trait_m
+            .def_id
+            .as_local()
+            .and_then(|def_id| {
+                let TraitItemKind::Fn(trait_m_sig, _) = &tcx.hir().expect_trait_item(def_id).kind else { bug!("{:?} is not a method", impl_m) };
+                let pos = trait_number_args.saturating_sub(1);
+                trait_m_sig.decl.inputs.get(pos).map(|arg| {
                     if pos == 0 {
                         arg.span
                     } else {
-                        arg.span.with_lo(impl_m_sig.decl.inputs[0].span.lo())
+                        arg.span.with_lo(trait_m_sig.decl.inputs[0].span.lo())
                     }
+                })
+            })
+            .or(trait_item_span);
+
+        let ImplItemKind::Fn(impl_m_sig, _) = &tcx.hir().expect_impl_item(impl_m.def_id.expect_local()).kind else { bug!("{:?} is not a method", impl_m) };
+        let pos = impl_number_args.saturating_sub(1);
+        let impl_span = impl_m_sig
+            .decl
+            .inputs
+            .get(pos)
+            .map(|arg| {
+                if pos == 0 {
+                    arg.span
                 } else {
-                    impl_m_span
+                    arg.span.with_lo(impl_m_sig.decl.inputs[0].span.lo())
                 }
-            }
-            _ => bug!("{:?} is not a method", impl_m),
-        };
+            })
+            .unwrap_or(impl_m_span);
+
         let mut err = struct_span_err!(
             tcx.sess,
             impl_span,
@@ -1424,6 +1393,7 @@ fn compare_number_of_method_arguments<'tcx>(
             tcx.def_path_str(trait_m.def_id),
             trait_number_args
         );
+
         if let Some(trait_span) = trait_span {
             err.span_label(
                 trait_span,
@@ -1435,6 +1405,7 @@ fn compare_number_of_method_arguments<'tcx>(
         } else {
             err.note_trait_signature(trait_m.name, trait_m.signature(tcx));
         }
+
         err.span_label(
             impl_span,
             format!(
@@ -1443,8 +1414,8 @@ fn compare_number_of_method_arguments<'tcx>(
                 impl_number_args
             ),
         );
-        let reported = err.emit();
-        return Err(reported);
+
+        return Err(err.emit());
     }
 
     Ok(())
@@ -1491,7 +1462,7 @@ fn compare_synthetic_generics<'tcx>(
                 // explicit generics
                 (true, false) => {
                     err.span_label(impl_span, "expected generic parameter, found `impl Trait`");
-                    (|| {
+                    let _: Option<_> = try {
                         // try taking the name from the trait impl
                         // FIXME: this is obviously suboptimal since the name can already be used
                         // as another generic argument
@@ -1524,26 +1495,23 @@ fn compare_synthetic_generics<'tcx>(
                             ],
                             Applicability::MaybeIncorrect,
                         );
-                        Some(())
-                    })();
+                    };
                 }
                 // The case where the trait method uses `impl Trait`, but the impl method uses
                 // explicit generics.
                 (false, true) => {
                     err.span_label(impl_span, "expected `impl Trait`, found generic parameter");
-                    (|| {
+                    let _: Option<_> = try {
                         let impl_m = impl_m.def_id.as_local()?;
                         let impl_m = tcx.hir().expect_impl_item(impl_m);
-                        let input_tys = match impl_m.kind {
-                            hir::ImplItemKind::Fn(ref sig, _) => sig.decl.inputs,
-                            _ => unreachable!(),
-                        };
+                        let hir::ImplItemKind::Fn(sig, _) = &impl_m.kind else { unreachable!() };
+                        let input_tys = sig.decl.inputs;
+
                         struct Visitor(Option<Span>, hir::def_id::LocalDefId);
                         impl<'v> intravisit::Visitor<'v> for Visitor {
                             fn visit_ty(&mut self, ty: &'v hir::Ty<'v>) {
                                 intravisit::walk_ty(self, ty);
-                                if let hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) =
-                                    ty.kind
+                                if let hir::TyKind::Path(hir::QPath::Resolved(None, path)) = ty.kind
                                     && let Res::Def(DefKind::TyParam, def_id) = path.res
                                     && def_id == self.1.to_def_id()
                                 {
@@ -1551,6 +1519,7 @@ fn compare_synthetic_generics<'tcx>(
                                 }
                             }
                         }
+
                         let mut visitor = Visitor(None, impl_def_id);
                         for ty in input_tys {
                             intravisit::Visitor::visit_ty(&mut visitor, ty);
@@ -1571,13 +1540,11 @@ fn compare_synthetic_generics<'tcx>(
                             ],
                             Applicability::MaybeIncorrect,
                         );
-                        Some(())
-                    })();
+                    };
                 }
                 _ => unreachable!(),
             }
-            let reported = err.emit();
-            error_found = Some(reported);
+            error_found = Some(err.emit());
         }
     }
     if let Some(reported) = error_found { Err(reported) } else { Ok(()) }
@@ -1737,10 +1704,8 @@ pub(super) fn compare_impl_const_raw(
         );
 
         // Locate the Span containing just the type of the offending impl
-        match tcx.hir().expect_impl_item(impl_const_item_def).kind {
-            ImplItemKind::Const(ref ty, _) => cause.span = ty.span,
-            _ => bug!("{:?} is not a impl const", impl_const_item),
-        }
+        let ImplItemKind::Const(ty, _) = tcx.hir().expect_impl_item(impl_const_item_def).kind else { bug!("{impl_const_item:?} is not a impl const") };
+        cause.span = ty.span;
 
         let mut diag = struct_span_err!(
             tcx.sess,
@@ -1752,10 +1717,8 @@ pub(super) fn compare_impl_const_raw(
 
         let trait_c_span = trait_const_item_def.as_local().map(|trait_c_def_id| {
             // Add a label to the Span containing just the type of the const
-            match tcx.hir().expect_trait_item(trait_c_def_id).kind {
-                TraitItemKind::Const(ref ty, _) => ty.span,
-                _ => bug!("{:?} is not a trait const", trait_const_item),
-            }
+            let TraitItemKind::Const(ty, _) = tcx.hir().expect_trait_item(trait_c_def_id).kind else { bug!("{trait_const_item:?} is not a trait const") };
+            ty.span
         });
 
         infcx.err_ctxt().note_type_err(
@@ -1797,7 +1760,7 @@ pub(super) fn compare_impl_ty<'tcx>(
 ) {
     debug!("compare_impl_type(impl_trait_ref={:?})", impl_trait_ref);
 
-    let _: Result<(), ErrorGuaranteed> = (|| {
+    let _: Result<(), ErrorGuaranteed> = try {
         compare_number_of_generics(tcx, impl_ty, trait_ty, trait_item_span, false)?;
 
         compare_generic_param_kinds(tcx, impl_ty, trait_ty, false)?;
@@ -1805,8 +1768,8 @@ pub(super) fn compare_impl_ty<'tcx>(
         let sp = tcx.def_span(impl_ty.def_id);
         compare_type_predicate_entailment(tcx, impl_ty, sp, trait_ty, impl_trait_ref)?;
 
-        check_type_bounds(tcx, trait_ty, impl_ty, impl_ty_span, impl_trait_ref)
-    })();
+        check_type_bounds(tcx, trait_ty, impl_ty, impl_ty_span, impl_trait_ref)?;
+    };
 }
 
 /// The equivalent of [compare_method_predicate_entailment], but for associated types
@@ -1828,8 +1791,7 @@ fn compare_type_predicate_entailment<'tcx>(
     check_region_bounds_on_impl_item(tcx, impl_ty, trait_ty, false)?;
 
     let impl_ty_own_bounds = impl_ty_predicates.instantiate_own(tcx, impl_substs);
-
-    if impl_ty_own_bounds.is_empty() {
+    if impl_ty_own_bounds.len() == 0 {
         // Nothing to check.
         return Ok(());
     }
@@ -1844,9 +1806,11 @@ fn compare_type_predicate_entailment<'tcx>(
     // associated type in the trait are assumed.
     let impl_predicates = tcx.predicates_of(impl_ty_predicates.parent.unwrap());
     let mut hybrid_preds = impl_predicates.instantiate_identity(tcx);
-    hybrid_preds
-        .predicates
-        .extend(trait_ty_predicates.instantiate_own(tcx, trait_to_impl_substs).predicates);
+    hybrid_preds.predicates.extend(
+        trait_ty_predicates
+            .instantiate_own(tcx, trait_to_impl_substs)
+            .map(|(predicate, _)| predicate),
+    );
 
     debug!("compare_type_predicate_entailment: bounds={:?}", hybrid_preds);
 
@@ -1862,9 +1826,7 @@ fn compare_type_predicate_entailment<'tcx>(
 
     debug!("compare_type_predicate_entailment: caller_bounds={:?}", param_env.caller_bounds());
 
-    assert_eq!(impl_ty_own_bounds.predicates.len(), impl_ty_own_bounds.spans.len());
-    for (span, predicate) in std::iter::zip(impl_ty_own_bounds.spans, impl_ty_own_bounds.predicates)
-    {
+    for (predicate, span) in impl_ty_own_bounds {
         let cause = ObligationCause::misc(span, impl_ty_hir_id);
         let predicate = ocx.normalize(&cause, param_env, predicate);
 
diff --git a/compiler/rustc_hir_analysis/src/check/intrinsicck.rs b/compiler/rustc_hir_analysis/src/check/intrinsicck.rs
index 17c4d0d482f..82030d82f57 100644
--- a/compiler/rustc_hir_analysis/src/check/intrinsicck.rs
+++ b/compiler/rustc_hir_analysis/src/check/intrinsicck.rs
@@ -351,7 +351,7 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
             }
 
             match *op {
-                hir::InlineAsmOperand::In { reg, ref expr } => {
+                hir::InlineAsmOperand::In { reg, expr } => {
                     self.check_asm_operand_type(
                         idx,
                         reg,
@@ -362,7 +362,7 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
                         &target_features,
                     );
                 }
-                hir::InlineAsmOperand::Out { reg, late: _, ref expr } => {
+                hir::InlineAsmOperand::Out { reg, late: _, expr } => {
                     if let Some(expr) = expr {
                         self.check_asm_operand_type(
                             idx,
@@ -375,7 +375,7 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
                         );
                     }
                 }
-                hir::InlineAsmOperand::InOut { reg, late: _, ref expr } => {
+                hir::InlineAsmOperand::InOut { reg, late: _, expr } => {
                     self.check_asm_operand_type(
                         idx,
                         reg,
@@ -386,7 +386,7 @@ impl<'a, 'tcx> InlineAsmCtxt<'a, 'tcx> {
                         &target_features,
                     );
                 }
-                hir::InlineAsmOperand::SplitInOut { reg, late: _, ref in_expr, ref out_expr } => {
+                hir::InlineAsmOperand::SplitInOut { reg, late: _, in_expr, out_expr } => {
                     let in_ty = self.check_asm_operand_type(
                         idx,
                         reg,
diff --git a/compiler/rustc_hir_analysis/src/check/region.rs b/compiler/rustc_hir_analysis/src/check/region.rs
index 479a10d6000..b28bfb1d54b 100644
--- a/compiler/rustc_hir_analysis/src/check/region.rs
+++ b/compiler/rustc_hir_analysis/src/check/region.rs
@@ -180,7 +180,7 @@ fn resolve_arm<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, arm: &'tcx hir
 
     visitor.terminating_scopes.insert(arm.body.hir_id.local_id);
 
-    if let Some(hir::Guard::If(ref expr)) = arm.guard {
+    if let Some(hir::Guard::If(expr)) = arm.guard {
         visitor.terminating_scopes.insert(expr.hir_id.local_id);
     }
 
@@ -242,8 +242,8 @@ fn resolve_expr<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, expr: &'tcx h
             // This ensures fixed size stacks.
             hir::ExprKind::Binary(
                 source_map::Spanned { node: hir::BinOpKind::And | hir::BinOpKind::Or, .. },
-                ref l,
-                ref r,
+                l,
+                r,
             ) => {
                 // expr is a short circuiting operator (|| or &&). As its
                 // functionality can't be overridden by traits, it always
@@ -288,20 +288,20 @@ fn resolve_expr<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, expr: &'tcx h
                     terminating(r.hir_id.local_id);
                 }
             }
-            hir::ExprKind::If(_, ref then, Some(ref otherwise)) => {
+            hir::ExprKind::If(_, then, Some(otherwise)) => {
                 terminating(then.hir_id.local_id);
                 terminating(otherwise.hir_id.local_id);
             }
 
-            hir::ExprKind::If(_, ref then, None) => {
+            hir::ExprKind::If(_, then, None) => {
                 terminating(then.hir_id.local_id);
             }
 
-            hir::ExprKind::Loop(ref body, _, _, _) => {
+            hir::ExprKind::Loop(body, _, _, _) => {
                 terminating(body.hir_id.local_id);
             }
 
-            hir::ExprKind::DropTemps(ref expr) => {
+            hir::ExprKind::DropTemps(expr) => {
                 // `DropTemps(expr)` does not denote a conditional scope.
                 // Rather, we want to achieve the same behavior as `{ let _t = expr; _t }`.
                 terminating(expr.hir_id.local_id);
@@ -396,7 +396,7 @@ fn resolve_expr<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, expr: &'tcx h
             let body = visitor.tcx.hir().body(body);
             visitor.visit_body(body);
         }
-        hir::ExprKind::AssignOp(_, ref left_expr, ref right_expr) => {
+        hir::ExprKind::AssignOp(_, left_expr, right_expr) => {
             debug!(
                 "resolve_expr - enabling pessimistic_yield, was previously {}",
                 prev_pessimistic
@@ -447,7 +447,7 @@ fn resolve_expr<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, expr: &'tcx h
             }
         }
 
-        hir::ExprKind::If(ref cond, ref then, Some(ref otherwise)) => {
+        hir::ExprKind::If(cond, then, Some(otherwise)) => {
             let expr_cx = visitor.cx;
             visitor.enter_scope(Scope { id: then.hir_id.local_id, data: ScopeData::IfThen });
             visitor.cx.var_parent = visitor.cx.parent;
@@ -457,7 +457,7 @@ fn resolve_expr<'tcx>(visitor: &mut RegionResolutionVisitor<'tcx>, expr: &'tcx h
             visitor.visit_expr(otherwise);
         }
 
-        hir::ExprKind::If(ref cond, ref then, None) => {
+        hir::ExprKind::If(cond, then, None) => {
             let expr_cx = visitor.cx;
             visitor.enter_scope(Scope { id: then.hir_id.local_id, data: ScopeData::IfThen });
             visitor.cx.var_parent = visitor.cx.parent;
@@ -641,21 +641,21 @@ fn resolve_local<'tcx>(
         match pat.kind {
             PatKind::Binding(hir::BindingAnnotation(hir::ByRef::Yes, _), ..) => true,
 
-            PatKind::Struct(_, ref field_pats, _) => {
+            PatKind::Struct(_, field_pats, _) => {
                 field_pats.iter().any(|fp| is_binding_pat(&fp.pat))
             }
 
-            PatKind::Slice(ref pats1, ref pats2, ref pats3) => {
+            PatKind::Slice(pats1, pats2, pats3) => {
                 pats1.iter().any(|p| is_binding_pat(&p))
                     || pats2.iter().any(|p| is_binding_pat(&p))
                     || pats3.iter().any(|p| is_binding_pat(&p))
             }
 
-            PatKind::Or(ref subpats)
-            | PatKind::TupleStruct(_, ref subpats, _)
-            | PatKind::Tuple(ref subpats, _) => subpats.iter().any(|p| is_binding_pat(&p)),
+            PatKind::Or(subpats)
+            | PatKind::TupleStruct(_, subpats, _)
+            | PatKind::Tuple(subpats, _) => subpats.iter().any(|p| is_binding_pat(&p)),
 
-            PatKind::Box(ref subpat) => is_binding_pat(&subpat),
+            PatKind::Box(subpat) => is_binding_pat(&subpat),
 
             PatKind::Ref(_, _)
             | PatKind::Binding(hir::BindingAnnotation(hir::ByRef::No, _), ..)
@@ -704,11 +704,11 @@ fn resolve_local<'tcx>(
                     record_rvalue_scope_if_borrow_expr(visitor, &subexpr, blk_id);
                 }
             }
-            hir::ExprKind::Cast(ref subexpr, _) => {
+            hir::ExprKind::Cast(subexpr, _) => {
                 record_rvalue_scope_if_borrow_expr(visitor, &subexpr, blk_id)
             }
-            hir::ExprKind::Block(ref block, _) => {
-                if let Some(ref subexpr) = block.expr {
+            hir::ExprKind::Block(block, _) => {
+                if let Some(subexpr) = block.expr {
                     record_rvalue_scope_if_borrow_expr(visitor, &subexpr, blk_id);
                 }
             }
diff --git a/compiler/rustc_hir_analysis/src/check/wfcheck.rs b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
index 912e0ec560b..11237afe8a0 100644
--- a/compiler/rustc_hir_analysis/src/check/wfcheck.rs
+++ b/compiler/rustc_hir_analysis/src/check/wfcheck.rs
@@ -32,7 +32,6 @@ use rustc_trait_selection::traits::{
 };
 
 use std::cell::LazyCell;
-use std::iter;
 use std::ops::{ControlFlow, Deref};
 
 pub(super) struct WfCheckingCtxt<'a, 'tcx> {
@@ -179,7 +178,7 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) {
         //
         // won't be allowed unless there's an *explicit* implementation of `Send`
         // for `T`
-        hir::ItemKind::Impl(ref impl_) => {
+        hir::ItemKind::Impl(impl_) => {
             let is_auto = tcx
                 .impl_trait_ref(def_id)
                 .map_or(false, |trait_ref| tcx.trait_is_auto(trait_ref.skip_binder().def_id));
@@ -225,15 +224,15 @@ fn check_item<'tcx>(tcx: TyCtxt<'tcx>, item: &'tcx hir::Item<'tcx>) {
         hir::ItemKind::Const(ty, ..) => {
             check_item_type(tcx, def_id, ty.span, false);
         }
-        hir::ItemKind::Struct(_, ref ast_generics) => {
+        hir::ItemKind::Struct(_, ast_generics) => {
             check_type_defn(tcx, item, false);
             check_variances_for_type_defn(tcx, item, ast_generics);
         }
-        hir::ItemKind::Union(_, ref ast_generics) => {
+        hir::ItemKind::Union(_, ast_generics) => {
             check_type_defn(tcx, item, true);
             check_variances_for_type_defn(tcx, item, ast_generics);
         }
-        hir::ItemKind::Enum(_, ref ast_generics) => {
+        hir::ItemKind::Enum(_, ast_generics) => {
             check_type_defn(tcx, item, true);
             check_variances_for_type_defn(tcx, item, ast_generics);
         }
@@ -1248,8 +1247,8 @@ fn check_impl<'tcx>(
     constness: hir::Constness,
 ) {
     enter_wf_checking_ctxt(tcx, item.span, item.owner_id.def_id, |wfcx| {
-        match *ast_trait_ref {
-            Some(ref ast_trait_ref) => {
+        match ast_trait_ref {
+            Some(ast_trait_ref) => {
                 // `#[rustc_reservation_impl]` impls are not real impls and
                 // therefore don't need to be WF (the trait's `Self: Trait` predicate
                 // won't hold).
@@ -1310,7 +1309,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
     let infcx = wfcx.infcx;
     let tcx = wfcx.tcx();
 
-    let predicates = tcx.bound_predicates_of(def_id.to_def_id());
+    let predicates = tcx.predicates_of(def_id.to_def_id());
     let generics = tcx.generics_of(def_id);
 
     let is_our_default = |def: &ty::GenericParamDef| match def.kind {
@@ -1411,7 +1410,6 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
 
     // Now we build the substituted predicates.
     let default_obligations = predicates
-        .0
         .predicates
         .iter()
         .flat_map(|&(pred, sp)| {
@@ -1430,7 +1428,7 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
                 }
 
                 fn visit_region(&mut self, _: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
-                    ControlFlow::BREAK
+                    ControlFlow::Break(())
                 }
 
                 fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
@@ -1442,13 +1440,13 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
             }
             let mut param_count = CountParams::default();
             let has_region = pred.visit_with(&mut param_count).is_break();
-            let substituted_pred = predicates.rebind(pred).subst(tcx, substs);
+            let substituted_pred = ty::EarlyBinder(pred).subst(tcx, substs);
             // Don't check non-defaulted params, dependent defaults (including lifetimes)
             // or preds with multiple params.
             if substituted_pred.has_non_region_param() || param_count.params.len() > 1 || has_region
             {
                 None
-            } else if predicates.0.predicates.iter().any(|&(p, _)| p == substituted_pred) {
+            } else if predicates.predicates.iter().any(|&(p, _)| p == substituted_pred) {
                 // Avoid duplication of predicates that contain no parameters, for example.
                 None
             } else {
@@ -1474,22 +1472,21 @@ fn check_where_clauses<'tcx>(wfcx: &WfCheckingCtxt<'_, 'tcx>, span: Span, def_id
             traits::Obligation::new(tcx, cause, wfcx.param_env, pred)
         });
 
-    let predicates = predicates.0.instantiate_identity(tcx);
+    let predicates = predicates.instantiate_identity(tcx);
 
     let predicates = wfcx.normalize(span, None, predicates);
 
     debug!(?predicates.predicates);
     assert_eq!(predicates.predicates.len(), predicates.spans.len());
-    let wf_obligations =
-        iter::zip(&predicates.predicates, &predicates.spans).flat_map(|(&p, &sp)| {
-            traits::wf::predicate_obligations(
-                infcx,
-                wfcx.param_env.without_const(),
-                wfcx.body_id,
-                p,
-                sp,
-            )
-        });
+    let wf_obligations = predicates.into_iter().flat_map(|(p, sp)| {
+        traits::wf::predicate_obligations(
+            infcx,
+            wfcx.param_env.without_const(),
+            wfcx.body_id,
+            p,
+            sp,
+        )
+    });
 
     let obligations: Vec<_> = wf_obligations.chain(default_obligations).collect();
     wfcx.register_obligations(obligations);
diff --git a/compiler/rustc_hir_analysis/src/coherence/builtin.rs b/compiler/rustc_hir_analysis/src/coherence/builtin.rs
index 4edd9221ab2..28c04087868 100644
--- a/compiler/rustc_hir_analysis/src/coherence/builtin.rs
+++ b/compiler/rustc_hir_analysis/src/coherence/builtin.rs
@@ -7,13 +7,15 @@ use rustc_hir as hir;
 use rustc_hir::def_id::{DefId, LocalDefId};
 use rustc_hir::lang_items::LangItem;
 use rustc_hir::ItemKind;
-use rustc_infer::infer;
 use rustc_infer::infer::outlives::env::OutlivesEnvironment;
 use rustc_infer::infer::TyCtxtInferExt;
+use rustc_infer::infer::{self, RegionResolutionError};
 use rustc_middle::ty::adjustment::CoerceUnsizedInfo;
 use rustc_middle::ty::{self, suggest_constraining_type_params, Ty, TyCtxt, TypeVisitable};
 use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt;
-use rustc_trait_selection::traits::misc::{can_type_implement_copy, CopyImplementationError};
+use rustc_trait_selection::traits::misc::{
+    type_allowed_to_implement_copy, CopyImplementationError, InfringingFieldsReason,
+};
 use rustc_trait_selection::traits::predicate_for_trait_def;
 use rustc_trait_selection::traits::{self, ObligationCause};
 use std::collections::BTreeMap;
@@ -54,12 +56,9 @@ fn visit_implementation_of_drop(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
         _ => {}
     }
 
-    let sp = match tcx.hir().expect_item(impl_did).kind {
-        ItemKind::Impl(ref impl_) => impl_.self_ty.span,
-        _ => bug!("expected Drop impl item"),
-    };
+    let ItemKind::Impl(impl_) = tcx.hir().expect_item(impl_did).kind else { bug!("expected Drop impl item") };
 
-    tcx.sess.emit_err(DropImplOnWrongItem { span: sp });
+    tcx.sess.emit_err(DropImplOnWrongItem { span: impl_.self_ty.span });
 }
 
 fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
@@ -82,7 +81,7 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
     };
 
     let cause = traits::ObligationCause::misc(span, impl_hir_id);
-    match can_type_implement_copy(tcx, param_env, self_type, cause) {
+    match type_allowed_to_implement_copy(tcx, param_env, self_type, cause) {
         Ok(()) => {}
         Err(CopyImplementationError::InfrigingFields(fields)) => {
             let mut err = struct_span_err!(
@@ -97,50 +96,70 @@ fn visit_implementation_of_copy(tcx: TyCtxt<'_>, impl_did: LocalDefId) {
             let mut errors: BTreeMap<_, Vec<_>> = Default::default();
             let mut bounds = vec![];
 
-            for (field, ty) in fields {
+            for (field, ty, reason) in fields {
                 let field_span = tcx.def_span(field.did);
-                let field_ty_span = match tcx.hir().get_if_local(field.did) {
-                    Some(hir::Node::Field(field_def)) => field_def.ty.span,
-                    _ => field_span,
-                };
                 err.span_label(field_span, "this field does not implement `Copy`");
-                // Spin up a new FulfillmentContext, so we can get the _precise_ reason
-                // why this field does not implement Copy. This is useful because sometimes
-                // it is not immediately clear why Copy is not implemented for a field, since
-                // all we point at is the field itself.
-                let infcx = tcx.infer_ctxt().ignoring_regions().build();
-                for error in traits::fully_solve_bound(
-                    &infcx,
-                    traits::ObligationCause::dummy_with_span(field_ty_span),
-                    param_env,
-                    ty,
-                    tcx.require_lang_item(LangItem::Copy, Some(span)),
-                ) {
-                    let error_predicate = error.obligation.predicate;
-                    // Only note if it's not the root obligation, otherwise it's trivial and
-                    // should be self-explanatory (i.e. a field literally doesn't implement Copy).
-
-                    // FIXME: This error could be more descriptive, especially if the error_predicate
-                    // contains a foreign type or if it's a deeply nested type...
-                    if error_predicate != error.root_obligation.predicate {
-                        errors
-                            .entry((ty.to_string(), error_predicate.to_string()))
-                            .or_default()
-                            .push(error.obligation.cause.span);
+
+                match reason {
+                    InfringingFieldsReason::Fulfill(fulfillment_errors) => {
+                        for error in fulfillment_errors {
+                            let error_predicate = error.obligation.predicate;
+                            // Only note if it's not the root obligation, otherwise it's trivial and
+                            // should be self-explanatory (i.e. a field literally doesn't implement Copy).
+
+                            // FIXME: This error could be more descriptive, especially if the error_predicate
+                            // contains a foreign type or if it's a deeply nested type...
+                            if error_predicate != error.root_obligation.predicate {
+                                errors
+                                    .entry((ty.to_string(), error_predicate.to_string()))
+                                    .or_default()
+                                    .push(error.obligation.cause.span);
+                            }
+                            if let ty::PredicateKind::Clause(ty::Clause::Trait(
+                                ty::TraitPredicate {
+                                    trait_ref,
+                                    polarity: ty::ImplPolarity::Positive,
+                                    ..
+                                },
+                            )) = error_predicate.kind().skip_binder()
+                            {
+                                let ty = trait_ref.self_ty();
+                                if let ty::Param(_) = ty.kind() {
+                                    bounds.push((
+                                        format!("{ty}"),
+                                        trait_ref.print_only_trait_path().to_string(),
+                                        Some(trait_ref.def_id),
+                                    ));
+                                }
+                            }
+                        }
                     }
-                    if let ty::PredicateKind::Clause(ty::Clause::Trait(ty::TraitPredicate {
-                        trait_ref,
-                        polarity: ty::ImplPolarity::Positive,
-                        ..
-                    })) = error_predicate.kind().skip_binder()
-                    {
-                        let ty = trait_ref.self_ty();
-                        if let ty::Param(_) = ty.kind() {
-                            bounds.push((
-                                format!("{ty}"),
-                                trait_ref.print_only_trait_path().to_string(),
-                                Some(trait_ref.def_id),
-                            ));
+                    InfringingFieldsReason::Regions(region_errors) => {
+                        for error in region_errors {
+                            let ty = ty.to_string();
+                            match error {
+                                RegionResolutionError::ConcreteFailure(origin, a, b) => {
+                                    let predicate = format!("{b}: {a}");
+                                    errors
+                                        .entry((ty.clone(), predicate.clone()))
+                                        .or_default()
+                                        .push(origin.span());
+                                    if let ty::RegionKind::ReEarlyBound(ebr) = *b && ebr.has_name() {
+                                        bounds.push((b.to_string(), a.to_string(), None));
+                                    }
+                                }
+                                RegionResolutionError::GenericBoundFailure(origin, a, b) => {
+                                    let predicate = format!("{a}: {b}");
+                                    errors
+                                        .entry((ty.clone(), predicate.clone()))
+                                        .or_default()
+                                        .push(origin.span());
+                                    if let infer::region_constraints::GenericKind::Param(_) = a {
+                                        bounds.push((a.to_string(), b.to_string(), None));
+                                    }
+                                }
+                                _ => continue,
+                            }
                         }
                     }
                 }
@@ -505,12 +524,11 @@ pub fn coerce_unsized_info<'tcx>(tcx: TyCtxt<'tcx>, impl_did: DefId) -> CoerceUn
                 return err_info;
             } else if diff_fields.len() > 1 {
                 let item = tcx.hir().expect_item(impl_did);
-                let span =
-                    if let ItemKind::Impl(hir::Impl { of_trait: Some(ref t), .. }) = item.kind {
-                        t.path.span
-                    } else {
-                        tcx.def_span(impl_did)
-                    };
+                let span = if let ItemKind::Impl(hir::Impl { of_trait: Some(t), .. }) = &item.kind {
+                    t.path.span
+                } else {
+                    tcx.def_span(impl_did)
+                };
 
                 struct_span_err!(
                     tcx.sess,
diff --git a/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs b/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs
index 6469f389bf9..dfb98240943 100644
--- a/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs
+++ b/compiler/rustc_hir_analysis/src/coherence/inherent_impls.rs
@@ -182,7 +182,7 @@ impl<'tcx> InherentCollect<'tcx> {
         }
 
         let item = self.tcx.hir().item(id);
-        let hir::ItemKind::Impl(hir::Impl { of_trait: None, self_ty: ty, ref items, .. }) = item.kind else {
+        let hir::ItemKind::Impl(hir::Impl { of_trait: None, self_ty: ty, items, .. }) = item.kind else {
             return;
         };
 
diff --git a/compiler/rustc_hir_analysis/src/coherence/orphan.rs b/compiler/rustc_hir_analysis/src/coherence/orphan.rs
index 0aadc9f311b..95b03eb8263 100644
--- a/compiler/rustc_hir_analysis/src/coherence/orphan.rs
+++ b/compiler/rustc_hir_analysis/src/coherence/orphan.rs
@@ -40,7 +40,7 @@ fn do_orphan_check_impl<'tcx>(
     let trait_def_id = trait_ref.def_id;
 
     let item = tcx.hir().expect_item(def_id);
-    let hir::ItemKind::Impl(ref impl_) = item.kind else {
+    let hir::ItemKind::Impl(impl_) = item.kind else {
         bug!("{:?} is not an impl: {:?}", def_id, item);
     };
     let sp = tcx.def_span(def_id);
@@ -416,13 +416,13 @@ fn fast_reject_auto_impl<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId, self_ty:
             if t != self.self_ty_root {
                 for impl_def_id in tcx.non_blanket_impls_for_ty(self.trait_def_id, t) {
                     match tcx.impl_polarity(impl_def_id) {
-                        ImplPolarity::Negative => return ControlFlow::BREAK,
+                        ImplPolarity::Negative => return ControlFlow::Break(()),
                         ImplPolarity::Reservation => {}
                         // FIXME(@lcnr): That's probably not good enough, idk
                         //
                         // We might just want to take the rustdoc code and somehow avoid
                         // explicit impls for `Self`.
-                        ImplPolarity::Positive => return ControlFlow::CONTINUE,
+                        ImplPolarity::Positive => return ControlFlow::Continue(()),
                     }
                 }
             }
@@ -440,7 +440,7 @@ fn fast_reject_auto_impl<'tcx>(tcx: TyCtxt<'tcx>, trait_def_id: DefId, self_ty:
                         }
                     }
 
-                    ControlFlow::CONTINUE
+                    ControlFlow::Continue(())
                 }
                 _ => t.super_visit_with(self),
             }
diff --git a/compiler/rustc_hir_analysis/src/coherence/unsafety.rs b/compiler/rustc_hir_analysis/src/coherence/unsafety.rs
index a485768e37b..fe6119dce87 100644
--- a/compiler/rustc_hir_analysis/src/coherence/unsafety.rs
+++ b/compiler/rustc_hir_analysis/src/coherence/unsafety.rs
@@ -11,7 +11,7 @@ use rustc_span::def_id::LocalDefId;
 pub(super) fn check_item(tcx: TyCtxt<'_>, def_id: LocalDefId) {
     debug_assert!(matches!(tcx.def_kind(def_id), DefKind::Impl));
     let item = tcx.hir().expect_item(def_id);
-    let hir::ItemKind::Impl(ref impl_) = item.kind else { bug!() };
+    let hir::ItemKind::Impl(impl_) = item.kind else { bug!() };
 
     if let Some(trait_ref) = tcx.impl_trait_ref(item.owner_id) {
         let trait_ref = trait_ref.subst_identity();
diff --git a/compiler/rustc_hir_analysis/src/collect.rs b/compiler/rustc_hir_analysis/src/collect.rs
index 35f47dfc1a5..c17778ce8bc 100644
--- a/compiler/rustc_hir_analysis/src/collect.rs
+++ b/compiler/rustc_hir_analysis/src/collect.rs
@@ -76,6 +76,7 @@ pub fn provide(providers: &mut Providers) {
         is_foreign_item,
         generator_kind,
         collect_mod_item_types,
+        is_type_alias_impl_trait,
         ..*providers
     };
 }
@@ -560,7 +561,7 @@ fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
     debug!("convert: item {} with id {}", it.ident, it.hir_id());
     let def_id = item_id.owner_id.def_id;
 
-    match it.kind {
+    match &it.kind {
         // These don't define types.
         hir::ItemKind::ExternCrate(_)
         | hir::ItemKind::Use(..)
@@ -568,7 +569,7 @@ fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
         | hir::ItemKind::Mod(_)
         | hir::ItemKind::GlobalAsm(_) => {}
         hir::ItemKind::ForeignMod { items, .. } => {
-            for item in items {
+            for item in *items {
                 let item = tcx.hir().foreign_item(item.id);
                 tcx.ensure().generics_of(item.owner_id);
                 tcx.ensure().type_of(item.owner_id);
@@ -618,7 +619,7 @@ fn convert_item(tcx: TyCtxt<'_>, item_id: hir::ItemId) {
             tcx.at(it.span).super_predicates_of(def_id);
             tcx.ensure().predicates_of(def_id);
         }
-        hir::ItemKind::Struct(ref struct_def, _) | hir::ItemKind::Union(ref struct_def, _) => {
+        hir::ItemKind::Struct(struct_def, _) | hir::ItemKind::Union(struct_def, _) => {
             tcx.ensure().generics_of(def_id);
             tcx.ensure().type_of(def_id);
             tcx.ensure().predicates_of(def_id);
@@ -853,14 +854,14 @@ fn adt_def(tcx: TyCtxt<'_>, def_id: DefId) -> ty::AdtDef<'_> {
     };
 
     let repr = tcx.repr_options_of_def(def_id.to_def_id());
-    let (kind, variants) = match item.kind {
-        ItemKind::Enum(ref def, _) => {
+    let (kind, variants) = match &item.kind {
+        ItemKind::Enum(def, _) => {
             let mut distance_from_explicit = 0;
             let variants = def
                 .variants
                 .iter()
                 .map(|v| {
-                    let discr = if let Some(ref e) = v.disr_expr {
+                    let discr = if let Some(e) = &v.disr_expr {
                         distance_from_explicit = 0;
                         ty::VariantDiscr::Explicit(e.def_id.to_def_id())
                     } else {
@@ -882,7 +883,7 @@ fn adt_def(tcx: TyCtxt<'_>, def_id: DefId) -> ty::AdtDef<'_> {
 
             (AdtKind::Enum, variants)
         }
-        ItemKind::Struct(ref def, _) | ItemKind::Union(ref def, _) => {
+        ItemKind::Struct(def, _) | ItemKind::Union(def, _) => {
             let adt_kind = match item.kind {
                 ItemKind::Struct(..) => AdtKind::Struct,
                 _ => AdtKind::Union,
@@ -1342,21 +1343,19 @@ fn suggest_impl_trait<'tcx>(
 fn impl_trait_ref(tcx: TyCtxt<'_>, def_id: DefId) -> Option<ty::EarlyBinder<ty::TraitRef<'_>>> {
     let icx = ItemCtxt::new(tcx, def_id);
     let item = tcx.hir().expect_item(def_id.expect_local());
-    match item.kind {
-        hir::ItemKind::Impl(ref impl_) => impl_
-            .of_trait
-            .as_ref()
-            .map(|ast_trait_ref| {
-                let selfty = tcx.type_of(def_id);
-                icx.astconv().instantiate_mono_trait_ref(
-                    ast_trait_ref,
-                    selfty,
-                    check_impl_constness(tcx, impl_.constness, ast_trait_ref),
-                )
-            })
-            .map(ty::EarlyBinder),
-        _ => bug!(),
-    }
+    let hir::ItemKind::Impl(impl_) = item.kind else { bug!() };
+    impl_
+        .of_trait
+        .as_ref()
+        .map(|ast_trait_ref| {
+            let selfty = tcx.type_of(def_id);
+            icx.astconv().instantiate_mono_trait_ref(
+                ast_trait_ref,
+                selfty,
+                check_impl_constness(tcx, impl_.constness, ast_trait_ref),
+            )
+        })
+        .map(ty::EarlyBinder)
 }
 
 fn check_impl_constness(
@@ -1511,7 +1510,7 @@ fn compute_sig_of_foreign_fn_decl<'tcx>(
         for (input, ty) in iter::zip(decl.inputs, fty.inputs().skip_binder()) {
             check(input, *ty)
         }
-        if let hir::FnRetTy::Return(ref ty) = decl.output {
+        if let hir::FnRetTy::Return(ty) = decl.output {
             check(ty, fty.output().skip_binder())
         }
     }
@@ -1537,3 +1536,13 @@ fn generator_kind(tcx: TyCtxt<'_>, def_id: DefId) -> Option<hir::GeneratorKind>
         _ => bug!("generator_kind applied to non-local def-id {:?}", def_id),
     }
 }
+
+fn is_type_alias_impl_trait<'tcx>(tcx: TyCtxt<'tcx>, def_id: DefId) -> bool {
+    match tcx.hir().get_if_local(def_id) {
+        Some(Node::Item(hir::Item { kind: hir::ItemKind::OpaqueTy(opaque), .. })) => {
+            matches!(opaque.origin, hir::OpaqueTyOrigin::TyAlias)
+        }
+        Some(_) => bug!("tried getting opaque_ty_origin for non-opaque: {:?}", def_id),
+        _ => bug!("tried getting opaque_ty_origin for non-local def-id {:?}", def_id),
+    }
+}
diff --git a/compiler/rustc_hir_analysis/src/collect/generics_of.rs b/compiler/rustc_hir_analysis/src/collect/generics_of.rs
index 9a5f447c260..014ee9fcc20 100644
--- a/compiler/rustc_hir_analysis/src/collect/generics_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/generics_of.rs
@@ -110,12 +110,12 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
                     // expressions' count (i.e. `N` in `[x; N]`), and explicit
                     // `enum` discriminants (i.e. `D` in `enum Foo { Bar = D }`),
                     // as they shouldn't be able to cause query cycle errors.
-                    Node::Expr(&Expr { kind: ExprKind::Repeat(_, ref constant), .. })
+                    Node::Expr(Expr { kind: ExprKind::Repeat(_, constant), .. })
                         if constant.hir_id() == hir_id =>
                     {
                         Some(parent_def_id.to_def_id())
                     }
-                    Node::Variant(Variant { disr_expr: Some(ref constant), .. })
+                    Node::Variant(Variant { disr_expr: Some(constant), .. })
                         if constant.hir_id == hir_id =>
                     {
                         Some(parent_def_id.to_def_id())
@@ -259,7 +259,7 @@ pub(super) fn generics_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::Generics {
 
     params.extend(ast_generics.params.iter().filter_map(|param| match param.kind {
         GenericParamKind::Lifetime { .. } => None,
-        GenericParamKind::Type { ref default, synthetic, .. } => {
+        GenericParamKind::Type { default, synthetic, .. } => {
             if default.is_some() {
                 match allow_defaults {
                     Defaults::Allowed => {}
@@ -426,26 +426,22 @@ fn has_late_bound_regions<'tcx>(tcx: TyCtxt<'tcx>, node: Node<'tcx>) -> Option<S
     }
 
     match node {
-        Node::TraitItem(item) => match item.kind {
-            hir::TraitItemKind::Fn(ref sig, _) => {
-                has_late_bound_regions(tcx, &item.generics, sig.decl)
-            }
+        Node::TraitItem(item) => match &item.kind {
+            hir::TraitItemKind::Fn(sig, _) => has_late_bound_regions(tcx, &item.generics, sig.decl),
             _ => None,
         },
-        Node::ImplItem(item) => match item.kind {
-            hir::ImplItemKind::Fn(ref sig, _) => {
-                has_late_bound_regions(tcx, &item.generics, sig.decl)
-            }
+        Node::ImplItem(item) => match &item.kind {
+            hir::ImplItemKind::Fn(sig, _) => has_late_bound_regions(tcx, &item.generics, sig.decl),
             _ => None,
         },
         Node::ForeignItem(item) => match item.kind {
-            hir::ForeignItemKind::Fn(fn_decl, _, ref generics) => {
+            hir::ForeignItemKind::Fn(fn_decl, _, generics) => {
                 has_late_bound_regions(tcx, generics, fn_decl)
             }
             _ => None,
         },
-        Node::Item(item) => match item.kind {
-            hir::ItemKind::Fn(ref sig, .., ref generics, _) => {
+        Node::Item(item) => match &item.kind {
+            hir::ItemKind::Fn(sig, .., generics, _) => {
                 has_late_bound_regions(tcx, generics, sig.decl)
             }
             _ => None,
diff --git a/compiler/rustc_hir_analysis/src/collect/item_bounds.rs b/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
index 62eef710ba4..8d479f1c3e3 100644
--- a/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
+++ b/compiler/rustc_hir_analysis/src/collect/item_bounds.rs
@@ -99,12 +99,16 @@ pub(super) fn explicit_item_bounds(
     }
 }
 
-pub(super) fn item_bounds(tcx: TyCtxt<'_>, def_id: DefId) -> &'_ ty::List<ty::Predicate<'_>> {
-    tcx.mk_predicates(
+pub(super) fn item_bounds(
+    tcx: TyCtxt<'_>,
+    def_id: DefId,
+) -> ty::EarlyBinder<&'_ ty::List<ty::Predicate<'_>>> {
+    let bounds = tcx.mk_predicates(
         util::elaborate_predicates(
             tcx,
             tcx.explicit_item_bounds(def_id).iter().map(|&(bound, _span)| bound),
         )
         .map(|obligation| obligation.predicate),
-    )
+    );
+    ty::EarlyBinder(bounds)
 }
diff --git a/compiler/rustc_hir_analysis/src/collect/lifetimes.rs b/compiler/rustc_hir_analysis/src/collect/lifetimes.rs
index 9435022ddf0..359122d4e16 100644
--- a/compiler/rustc_hir_analysis/src/collect/lifetimes.rs
+++ b/compiler/rustc_hir_analysis/src/collect/lifetimes.rs
@@ -428,7 +428,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
             _ => {}
         }
         match item.kind {
-            hir::ItemKind::Fn(_, ref generics, _) => {
+            hir::ItemKind::Fn(_, generics, _) => {
                 self.visit_early_late(item.hir_id(), generics, |this| {
                     intravisit::walk_item(this, item);
                 });
@@ -508,13 +508,13 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                     this.with(scope, |this| intravisit::walk_item(this, item))
                 });
             }
-            hir::ItemKind::TyAlias(_, ref generics)
-            | hir::ItemKind::Enum(_, ref generics)
-            | hir::ItemKind::Struct(_, ref generics)
-            | hir::ItemKind::Union(_, ref generics)
-            | hir::ItemKind::Trait(_, _, ref generics, ..)
-            | hir::ItemKind::TraitAlias(ref generics, ..)
-            | hir::ItemKind::Impl(hir::Impl { ref generics, .. }) => {
+            hir::ItemKind::TyAlias(_, generics)
+            | hir::ItemKind::Enum(_, generics)
+            | hir::ItemKind::Struct(_, generics)
+            | hir::ItemKind::Union(_, generics)
+            | hir::ItemKind::Trait(_, _, generics, ..)
+            | hir::ItemKind::TraitAlias(generics, ..)
+            | hir::ItemKind::Impl(&hir::Impl { generics, .. }) => {
                 // These kinds of items have only early-bound lifetime parameters.
                 let lifetimes = generics
                     .params
@@ -544,7 +544,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
 
     fn visit_foreign_item(&mut self, item: &'tcx hir::ForeignItem<'tcx>) {
         match item.kind {
-            hir::ForeignItemKind::Fn(_, _, ref generics) => {
+            hir::ForeignItemKind::Fn(_, _, generics) => {
                 self.visit_early_late(item.hir_id(), generics, |this| {
                     intravisit::walk_foreign_item(this, item);
                 })
@@ -561,7 +561,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
     #[instrument(level = "debug", skip(self))]
     fn visit_ty(&mut self, ty: &'tcx hir::Ty<'tcx>) {
         match ty.kind {
-            hir::TyKind::BareFn(ref c) => {
+            hir::TyKind::BareFn(c) => {
                 let (lifetimes, binders): (FxIndexMap<LocalDefId, Region>, Vec<_>) = c
                     .generic_params
                     .iter()
@@ -587,7 +587,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                     intravisit::walk_ty(this, ty);
                 });
             }
-            hir::TyKind::TraitObject(bounds, ref lifetime, _) => {
+            hir::TyKind::TraitObject(bounds, lifetime, _) => {
                 debug!(?bounds, ?lifetime, "TraitObject");
                 let scope = Scope::TraitRefBoundary { s: self.scope };
                 self.with(scope, |this| {
@@ -617,7 +617,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                     LifetimeName::Error => {}
                 }
             }
-            hir::TyKind::Ref(ref lifetime_ref, ref mt) => {
+            hir::TyKind::Ref(lifetime_ref, ref mt) => {
                 self.visit_lifetime(lifetime_ref);
                 let scope = Scope::ObjectLifetimeDefault {
                     lifetime: self.map.defs.get(&lifetime_ref.hir_id).cloned(),
@@ -632,7 +632,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                 //                 ^                  ^ this gets resolved in the scope of
                 //                                      the opaque_ty generics
                 let opaque_ty = self.tcx.hir().item(item_id);
-                match opaque_ty.kind {
+                match &opaque_ty.kind {
                     hir::ItemKind::OpaqueTy(hir::OpaqueTy {
                         origin: hir::OpaqueTyOrigin::TyAlias,
                         ..
@@ -655,7 +655,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                         origin: hir::OpaqueTyOrigin::FnReturn(..) | hir::OpaqueTyOrigin::AsyncFn(..),
                         ..
                     }) => {}
-                    ref i => bug!("`impl Trait` pointed to non-opaque type?? {:#?}", i),
+                    i => bug!("`impl Trait` pointed to non-opaque type?? {:#?}", i),
                 };
 
                 // Resolve the lifetimes that are applied to the opaque type.
@@ -720,7 +720,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                     intravisit::walk_trait_item(this, trait_item)
                 });
             }
-            Type(bounds, ref ty) => {
+            Type(bounds, ty) => {
                 let generics = &trait_item.generics;
                 let lifetimes = generics
                     .params
@@ -766,7 +766,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
             Fn(..) => self.visit_early_late(impl_item.hir_id(), &impl_item.generics, |this| {
                 intravisit::walk_impl_item(this, impl_item)
             }),
-            Type(ref ty) => {
+            Type(ty) => {
                 let generics = &impl_item.generics;
                 let lifetimes: FxIndexMap<LocalDefId, Region> = generics
                     .params
@@ -817,7 +817,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
     fn visit_path(&mut self, path: &hir::Path<'tcx>, _: hir::HirId) {
         for (i, segment) in path.segments.iter().enumerate() {
             let depth = path.segments.len() - i - 1;
-            if let Some(ref args) = segment.args {
+            if let Some(args) = segment.args {
                 self.visit_segment_args(path.res, depth, args);
             }
         }
@@ -833,7 +833,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
     ) {
         let output = match fd.output {
             hir::FnRetTy::DefaultReturn(_) => None,
-            hir::FnRetTy::Return(ref ty) => Some(&**ty),
+            hir::FnRetTy::Return(ty) => Some(ty),
         };
         self.visit_fn_like_elision(&fd.inputs, output, matches!(fk, intravisit::FnKind::Closure));
         intravisit::walk_fn_kind(self, fk);
@@ -846,13 +846,13 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
             for param in generics.params {
                 match param.kind {
                     GenericParamKind::Lifetime { .. } => {}
-                    GenericParamKind::Type { ref default, .. } => {
-                        if let Some(ref ty) = default {
-                            this.visit_ty(&ty);
+                    GenericParamKind::Type { default, .. } => {
+                        if let Some(ty) = default {
+                            this.visit_ty(ty);
                         }
                     }
-                    GenericParamKind::Const { ref ty, default } => {
-                        this.visit_ty(&ty);
+                    GenericParamKind::Const { ty, default } => {
+                        this.visit_ty(ty);
                         if let Some(default) = default {
                             this.visit_body(this.tcx.hir().body(default.body));
                         }
@@ -863,9 +863,9 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                 match predicate {
                     &hir::WherePredicate::BoundPredicate(hir::WhereBoundPredicate {
                         hir_id,
-                        ref bounded_ty,
+                        bounded_ty,
                         bounds,
-                        ref bound_generic_params,
+                        bound_generic_params,
                         origin,
                         ..
                     }) => {
@@ -905,7 +905,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                         })
                     }
                     &hir::WherePredicate::RegionPredicate(hir::WhereRegionPredicate {
-                        ref lifetime,
+                        lifetime,
                         bounds,
                         ..
                     }) => {
@@ -914,7 +914,7 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
 
                         if lifetime.res != hir::LifetimeName::Static {
                             for bound in bounds {
-                                let hir::GenericBound::Outlives(ref lt) = bound else {
+                                let hir::GenericBound::Outlives(lt) = bound else {
                                     continue;
                                 };
                                 if lt.res != hir::LifetimeName::Static {
@@ -939,8 +939,8 @@ impl<'a, 'tcx> Visitor<'tcx> for LifetimeContext<'a, 'tcx> {
                         }
                     }
                     &hir::WherePredicate::EqPredicate(hir::WhereEqPredicate {
-                        ref lhs_ty,
-                        ref rhs_ty,
+                        lhs_ty,
+                        rhs_ty,
                         ..
                     }) => {
                         this.visit_ty(lhs_ty);
@@ -1042,7 +1042,7 @@ fn object_lifetime_default(tcx: TyCtxt<'_>, param_def_id: DefId) -> ObjectLifeti
                 }
 
                 for bound in bound.bounds {
-                    if let hir::GenericBound::Outlives(ref lifetime) = *bound {
+                    if let hir::GenericBound::Outlives(lifetime) = bound {
                         set.insert(lifetime.res);
                     }
                 }
@@ -1828,7 +1828,7 @@ fn is_late_bound_map(tcx: TyCtxt<'_>, def_id: LocalDefId) -> Option<&FxIndexSet<
                     }
                 }
 
-                hir::TyKind::Path(hir::QPath::Resolved(None, ref path)) => {
+                hir::TyKind::Path(hir::QPath::Resolved(None, path)) => {
                     // consider only the lifetimes on the final
                     // segment; I am not sure it's even currently
                     // valid to have them elsewhere, but even if it
diff --git a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
index 62ad0a6c0fc..46b277d9803 100644
--- a/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/predicates_of.rs
@@ -85,30 +85,30 @@ fn gather_explicit_predicates_of(tcx: TyCtxt<'_>, def_id: DefId) -> ty::GenericP
         Node::ImplItem(item) => item.generics,
 
         Node::Item(item) => match item.kind {
-            ItemKind::Impl(ref impl_) => {
+            ItemKind::Impl(impl_) => {
                 if impl_.defaultness.is_default() {
                     is_default_impl_trait =
                         tcx.impl_trait_ref(def_id).map(|t| ty::Binder::dummy(t.subst_identity()));
                 }
-                &impl_.generics
+                impl_.generics
             }
-            ItemKind::Fn(.., ref generics, _)
-            | ItemKind::TyAlias(_, ref generics)
-            | ItemKind::Enum(_, ref generics)
-            | ItemKind::Struct(_, ref generics)
-            | ItemKind::Union(_, ref generics) => *generics,
+            ItemKind::Fn(.., generics, _)
+            | ItemKind::TyAlias(_, generics)
+            | ItemKind::Enum(_, generics)
+            | ItemKind::Struct(_, generics)
+            | ItemKind::Union(_, generics) => generics,
 
-            ItemKind::Trait(_, _, ref generics, ..) | ItemKind::TraitAlias(ref generics, _) => {
+            ItemKind::Trait(_, _, generics, ..) | ItemKind::TraitAlias(generics, _) => {
                 is_trait = Some(ty::TraitRef::identity(tcx, def_id));
-                *generics
+                generics
             }
-            ItemKind::OpaqueTy(OpaqueTy { ref generics, .. }) => generics,
+            ItemKind::OpaqueTy(OpaqueTy { generics, .. }) => generics,
             _ => NO_GENERICS,
         },
 
         Node::ForeignItem(item) => match item.kind {
             ForeignItemKind::Static(..) => NO_GENERICS,
-            ForeignItemKind::Fn(_, _, ref generics) => *generics,
+            ForeignItemKind::Fn(_, _, generics) => generics,
             ForeignItemKind::Type => NO_GENERICS,
         },
 
@@ -350,7 +350,7 @@ fn const_evaluatable_predicates_of(
     let node = tcx.hir().get(hir_id);
 
     let mut collector = ConstCollector { tcx, preds: FxIndexSet::default() };
-    if let hir::Node::Item(item) = node && let hir::ItemKind::Impl(ref impl_) = item.kind {
+    if let hir::Node::Item(item) = node && let hir::ItemKind::Impl(impl_) = item.kind {
         if let Some(of_trait) = &impl_.of_trait {
             debug!("const_evaluatable_predicates_of({:?}): visit impl trait_ref", def_id);
             collector.visit_trait_ref(of_trait);
@@ -511,8 +511,8 @@ pub(super) fn super_predicates_that_define_assoc_type(
         };
 
         let (generics, bounds) = match item.kind {
-            hir::ItemKind::Trait(.., ref generics, ref supertraits, _) => (generics, supertraits),
-            hir::ItemKind::TraitAlias(ref generics, ref supertraits) => (generics, supertraits),
+            hir::ItemKind::Trait(.., generics, supertraits, _) => (generics, supertraits),
+            hir::ItemKind::TraitAlias(generics, supertraits) => (generics, supertraits),
             _ => span_bug!(item.span, "super_predicates invoked on non-trait"),
         };
 
@@ -612,18 +612,18 @@ pub(super) fn type_param_predicates(
 
         Node::Item(item) => {
             match item.kind {
-                ItemKind::Fn(.., ref generics, _)
-                | ItemKind::Impl(hir::Impl { ref generics, .. })
-                | ItemKind::TyAlias(_, ref generics)
+                ItemKind::Fn(.., generics, _)
+                | ItemKind::Impl(&hir::Impl { generics, .. })
+                | ItemKind::TyAlias(_, generics)
                 | ItemKind::OpaqueTy(OpaqueTy {
-                    ref generics,
+                    generics,
                     origin: hir::OpaqueTyOrigin::TyAlias,
                     ..
                 })
-                | ItemKind::Enum(_, ref generics)
-                | ItemKind::Struct(_, ref generics)
-                | ItemKind::Union(_, ref generics) => generics,
-                ItemKind::Trait(_, _, ref generics, ..) => {
+                | ItemKind::Enum(_, generics)
+                | ItemKind::Struct(_, generics)
+                | ItemKind::Union(_, generics) => generics,
+                ItemKind::Trait(_, _, generics, ..) => {
                     // Implied `Self: Trait` and supertrait bounds.
                     if param_id == item_hir_id {
                         let identity_trait_ref = ty::TraitRef::identity(tcx, item_def_id);
@@ -637,7 +637,7 @@ pub(super) fn type_param_predicates(
         }
 
         Node::ForeignItem(item) => match item.kind {
-            ForeignItemKind::Fn(_, _, ref generics) => generics,
+            ForeignItemKind::Fn(_, _, generics) => generics,
             _ => return result,
         },
 
@@ -681,8 +681,8 @@ impl<'tcx> ItemCtxt<'tcx> {
         ast_generics
             .predicates
             .iter()
-            .filter_map(|wp| match *wp {
-                hir::WherePredicate::BoundPredicate(ref bp) => Some(bp),
+            .filter_map(|wp| match wp {
+                hir::WherePredicate::BoundPredicate(bp) => Some(bp),
                 _ => None,
             })
             .flat_map(|bp| {
diff --git a/compiler/rustc_hir_analysis/src/collect/type_of.rs b/compiler/rustc_hir_analysis/src/collect/type_of.rs
index 1f9a9f80302..5e388a2f2ba 100644
--- a/compiler/rustc_hir_analysis/src/collect/type_of.rs
+++ b/compiler/rustc_hir_analysis/src/collect/type_of.rs
@@ -379,7 +379,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
             ForeignItemKind::Type => tcx.mk_foreign(def_id.to_def_id()),
         },
 
-        Node::Ctor(&ref def) | Node::Variant(Variant { data: ref def, .. }) => match *def {
+        Node::Ctor(def) | Node::Variant(Variant { data: def, .. }) => match def {
             VariantData::Unit(..) | VariantData::Struct(..) => {
                 tcx.type_of(tcx.hir().get_parent_item(hir_id))
             }
@@ -404,17 +404,17 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
         Node::AnonConst(_) => {
             let parent_node = tcx.hir().get_parent(hir_id);
             match parent_node {
-                Node::Ty(&Ty { kind: TyKind::Array(_, ref constant), .. })
-                | Node::Expr(&Expr { kind: ExprKind::Repeat(_, ref constant), .. })
+                Node::Ty(Ty { kind: TyKind::Array(_, constant), .. })
+                | Node::Expr(Expr { kind: ExprKind::Repeat(_, constant), .. })
                     if constant.hir_id() == hir_id =>
                 {
                     tcx.types.usize
                 }
-                Node::Ty(&Ty { kind: TyKind::Typeof(ref e), .. }) if e.hir_id == hir_id => {
+                Node::Ty(Ty { kind: TyKind::Typeof(e), .. }) if e.hir_id == hir_id => {
                     tcx.typeck(def_id).node_type(e.hir_id)
                 }
 
-                Node::Expr(&Expr { kind: ExprKind::ConstBlock(ref anon_const), .. })
+                Node::Expr(Expr { kind: ExprKind::ConstBlock(anon_const), .. })
                     if anon_const.hir_id == hir_id =>
                 {
                     let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id());
@@ -434,18 +434,19 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
                     tcx.typeck(def_id).node_type(hir_id)
                 }
 
-                Node::Variant(Variant { disr_expr: Some(ref e), .. }) if e.hir_id == hir_id => {
+                Node::Variant(Variant { disr_expr: Some(e), .. }) if e.hir_id == hir_id => {
                     tcx.adt_def(tcx.hir().get_parent_item(hir_id)).repr().discr_type().to_ty(tcx)
                 }
 
                 Node::TypeBinding(
-                    binding @ &TypeBinding {
+                    TypeBinding {
                         hir_id: binding_id,
-                        kind: TypeBindingKind::Equality { term: Term::Const(ref e) },
+                        kind: TypeBindingKind::Equality { term: Term::Const(e) },
+                        ident,
                         ..
                     },
                 ) if let Node::TraitRef(trait_ref) =
-                    tcx.hir().get_parent(binding_id)
+                    tcx.hir().get_parent(*binding_id)
                     && e.hir_id == hir_id =>
                 {
                     let Some(trait_def_id) = trait_ref.trait_def_id() else {
@@ -454,7 +455,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
                     let assoc_items = tcx.associated_items(trait_def_id);
                     let assoc_item = assoc_items.find_by_name_and_kind(
                         tcx,
-                        binding.ident,
+                        *ident,
                         ty::AssocKind::Const,
                         def_id.to_def_id(),
                     );
@@ -470,9 +471,9 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
                 }
 
                 Node::TypeBinding(
-                    binding @ &TypeBinding { hir_id: binding_id, gen_args, ref kind, .. },
+                    TypeBinding { hir_id: binding_id, gen_args, kind, ident, .. },
                 ) if let Node::TraitRef(trait_ref) =
-                    tcx.hir().get_parent(binding_id)
+                    tcx.hir().get_parent(*binding_id)
                     && let Some((idx, _)) =
                         gen_args.args.iter().enumerate().find(|(_, arg)| {
                             if let GenericArg::Const(ct) = arg {
@@ -488,7 +489,7 @@ pub(super) fn type_of(tcx: TyCtxt<'_>, def_id: DefId) -> Ty<'_> {
                     let assoc_items = tcx.associated_items(trait_def_id);
                     let assoc_item = assoc_items.find_by_name_and_kind(
                         tcx,
-                        binding.ident,
+                        *ident,
                         match kind {
                             // I think `<A: T>` type bindings requires that `A` is a type
                             TypeBindingKind::Constraint { .. }
diff --git a/compiler/rustc_hir_analysis/src/constrained_generic_params.rs b/compiler/rustc_hir_analysis/src/constrained_generic_params.rs
index 95c971c0d78..56cc1d8fadc 100644
--- a/compiler/rustc_hir_analysis/src/constrained_generic_params.rs
+++ b/compiler/rustc_hir_analysis/src/constrained_generic_params.rs
@@ -61,7 +61,7 @@ impl<'tcx> TypeVisitor<'tcx> for ParameterCollector {
         match *t.kind() {
             ty::Alias(ty::Projection, ..) if !self.include_nonconstraining => {
                 // projections are not injective
-                return ControlFlow::CONTINUE;
+                return ControlFlow::Continue(());
             }
             ty::Param(data) => {
                 self.parameters.push(Parameter::from(data));
@@ -76,7 +76,7 @@ impl<'tcx> TypeVisitor<'tcx> for ParameterCollector {
         if let ty::ReEarlyBound(data) = *r {
             self.parameters.push(Parameter::from(data));
         }
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 
     fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
diff --git a/compiler/rustc_hir_analysis/src/hir_wf_check.rs b/compiler/rustc_hir_analysis/src/hir_wf_check.rs
index 2dbfc1bc9a2..17dbb126bd1 100644
--- a/compiler/rustc_hir_analysis/src/hir_wf_check.rs
+++ b/compiler/rustc_hir_analysis/src/hir_wf_check.rs
@@ -128,7 +128,7 @@ fn diagnostic_hir_wf_check<'tcx>(
             },
             hir::Node::Item(item) => match item.kind {
                 hir::ItemKind::Static(ty, _, _) | hir::ItemKind::Const(ty, _) => vec![ty],
-                hir::ItemKind::Impl(ref impl_) => match &impl_.of_trait {
+                hir::ItemKind::Impl(impl_) => match &impl_.of_trait {
                     Some(t) => t
                         .path
                         .segments
diff --git a/compiler/rustc_hir_analysis/src/lib.rs b/compiler/rustc_hir_analysis/src/lib.rs
index 9f8da463650..02548ae893f 100644
--- a/compiler/rustc_hir_analysis/src/lib.rs
+++ b/compiler/rustc_hir_analysis/src/lib.rs
@@ -114,6 +114,7 @@ use rustc_trait_selection::traits::error_reporting::TypeErrCtxtExt as _;
 use rustc_trait_selection::traits::{self, ObligationCause, ObligationCauseCode};
 
 use std::iter;
+use std::ops::Not;
 
 use astconv::AstConv;
 use bounds::Bounds;
@@ -203,12 +204,8 @@ fn check_main_fn_ty(tcx: TyCtxt<'_>, main_def_id: DefId) {
         }
         let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
         match tcx.hir().find(hir_id) {
-            Some(Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, ref generics, _), .. })) => {
-                if !generics.params.is_empty() {
-                    Some(generics.span)
-                } else {
-                    None
-                }
+            Some(Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, generics, _), .. })) => {
+                generics.params.is_empty().not().then(|| generics.span)
             }
             _ => {
                 span_bug!(tcx.def_span(def_id), "main has a non-function type");
@@ -222,7 +219,7 @@ fn check_main_fn_ty(tcx: TyCtxt<'_>, main_def_id: DefId) {
         }
         let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
         match tcx.hir().find(hir_id) {
-            Some(Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, ref generics, _), .. })) => {
+            Some(Node::Item(hir::Item { kind: hir::ItemKind::Fn(_, generics, _), .. })) => {
                 Some(generics.where_clause_span)
             }
             _ => {
@@ -244,7 +241,7 @@ fn check_main_fn_ty(tcx: TyCtxt<'_>, main_def_id: DefId) {
         }
         let hir_id = tcx.hir().local_def_id_to_hir_id(def_id.expect_local());
         match tcx.hir().find(hir_id) {
-            Some(Node::Item(hir::Item { kind: hir::ItemKind::Fn(ref fn_sig, _, _), .. })) => {
+            Some(Node::Item(hir::Item { kind: hir::ItemKind::Fn(fn_sig, _, _), .. })) => {
                 Some(fn_sig.decl.output.span())
             }
             _ => {
@@ -374,7 +371,7 @@ fn check_start_fn_ty(tcx: TyCtxt<'_>, start_def_id: DefId) {
     match start_t.kind() {
         ty::FnDef(..) => {
             if let Some(Node::Item(it)) = tcx.hir().find(start_id) {
-                if let hir::ItemKind::Fn(ref sig, ref generics, _) = it.kind {
+                if let hir::ItemKind::Fn(sig, generics, _) = &it.kind {
                     let mut error = false;
                     if !generics.params.is_empty() {
                         struct_span_err!(
diff --git a/compiler/rustc_hir_analysis/src/outlives/utils.rs b/compiler/rustc_hir_analysis/src/outlives/utils.rs
index c930b921b75..9459c5f54ab 100644
--- a/compiler/rustc_hir_analysis/src/outlives/utils.rs
+++ b/compiler/rustc_hir_analysis/src/outlives/utils.rs
@@ -80,8 +80,8 @@ pub(crate) fn insert_outlives_predicate<'tcx>(
                             .or_insert(span);
                     }
 
-                    Component::Projection(proj_ty) => {
-                        // This would arise from something like:
+                    Component::Alias(alias_ty) => {
+                        // This would either arise from something like:
                         //
                         // ```
                         // struct Foo<'a, T: Iterator> {
@@ -89,15 +89,7 @@ pub(crate) fn insert_outlives_predicate<'tcx>(
                         // }
                         // ```
                         //
-                        // Here we want to add an explicit `where <T as Iterator>::Item: 'a`.
-                        let ty: Ty<'tcx> = tcx.mk_projection(proj_ty.def_id, proj_ty.substs);
-                        required_predicates
-                            .entry(ty::OutlivesPredicate(ty.into(), outlived_region))
-                            .or_insert(span);
-                    }
-
-                    Component::Opaque(def_id, substs) => {
-                        // This would arise from something like:
+                        // or:
                         //
                         // ```rust
                         // type Opaque<T> = impl Sized;
@@ -105,15 +97,15 @@ pub(crate) fn insert_outlives_predicate<'tcx>(
                         // struct Ss<'a, T>(&'a Opaque<T>);
                         // ```
                         //
-                        // Here we want to have an implied bound `Opaque<T>: 'a`
-
-                        let ty = tcx.mk_opaque(def_id, substs);
+                        // Here we want to add an explicit `where <T as Iterator>::Item: 'a`
+                        // or `Opaque<T>: 'a` depending on the alias kind.
+                        let ty = alias_ty.to_ty(tcx);
                         required_predicates
                             .entry(ty::OutlivesPredicate(ty.into(), outlived_region))
                             .or_insert(span);
                     }
 
-                    Component::EscapingProjection(_) => {
+                    Component::EscapingAlias(_) => {
                         // As above, but the projection involves
                         // late-bound regions. Therefore, the WF
                         // requirement is not checked in type definition
diff --git a/compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs b/compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs
index 574b1e8b485..9133e6540d4 100644
--- a/compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs
+++ b/compiler/rustc_hir_analysis/src/structured_errors/wrong_number_of_generic_args.rs
@@ -727,8 +727,8 @@ impl<'a, 'tcx> WrongNumberOfGenericArgs<'a, 'tcx> {
         if let Some(parent_node) = self.tcx.hir().opt_parent_id(self.path_segment.hir_id)
         && let Some(parent_node) = self.tcx.hir().find(parent_node)
         && let hir::Node::Expr(expr) = parent_node {
-            match expr.kind {
-                hir::ExprKind::Path(ref qpath) => {
+            match &expr.kind {
+                hir::ExprKind::Path(qpath) => {
                     self.suggest_moving_args_from_assoc_fn_to_trait_for_qualified_path(
                         err,
                         qpath,
diff --git a/compiler/rustc_hir_analysis/src/variance/mod.rs b/compiler/rustc_hir_analysis/src/variance/mod.rs
index 24008f88814..079070be279 100644
--- a/compiler/rustc_hir_analysis/src/variance/mod.rs
+++ b/compiler/rustc_hir_analysis/src/variance/mod.rs
@@ -92,7 +92,7 @@ fn variance_of_opaque(tcx: TyCtxt<'_>, item_def_id: LocalDefId) -> &[ty::Varianc
                         a.visit_with(self)?;
                     }
                 }
-                ControlFlow::CONTINUE
+                ControlFlow::Continue(())
             } else {
                 substs.visit_with(self)
             }
diff --git a/compiler/rustc_hir_analysis/src/variance/solve.rs b/compiler/rustc_hir_analysis/src/variance/solve.rs
index c9b59d35704..a17edb598ad 100644
--- a/compiler/rustc_hir_analysis/src/variance/solve.rs
+++ b/compiler/rustc_hir_analysis/src/variance/solve.rs
@@ -5,8 +5,7 @@
 //! optimal solution to the constraints. The final variance for each
 //! inferred is then written into the `variance_map` in the tcx.
 
-use rustc_data_structures::fx::FxHashMap;
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::DefIdMap;
 use rustc_middle::ty;
 
 use super::constraints::*;
@@ -28,8 +27,8 @@ pub fn solve_constraints<'tcx>(
     let ConstraintContext { terms_cx, constraints, .. } = constraints_cx;
 
     let mut solutions = vec![ty::Bivariant; terms_cx.inferred_terms.len()];
-    for &(id, ref variances) in &terms_cx.lang_items {
-        let InferredIndex(start) = terms_cx.inferred_starts[&id];
+    for (id, variances) in &terms_cx.lang_items {
+        let InferredIndex(start) = terms_cx.inferred_starts[id];
         for (i, &variance) in variances.iter().enumerate() {
             solutions[start + i] = variance;
         }
@@ -89,14 +88,12 @@ impl<'a, 'tcx> SolveContext<'a, 'tcx> {
         }
     }
 
-    fn create_map(&self) -> FxHashMap<DefId, &'tcx [ty::Variance]> {
+    fn create_map(&self) -> DefIdMap<&'tcx [ty::Variance]> {
         let tcx = self.terms_cx.tcx;
 
         let solutions = &self.solutions;
-        self.terms_cx
-            .inferred_starts
-            .iter()
-            .map(|(&def_id, &InferredIndex(start))| {
+        DefIdMap::from(self.terms_cx.inferred_starts.items().map(
+            |(&def_id, &InferredIndex(start))| {
                 let generics = tcx.generics_of(def_id);
                 let count = generics.count();
 
@@ -115,8 +112,8 @@ impl<'a, 'tcx> SolveContext<'a, 'tcx> {
                 }
 
                 (def_id.to_def_id(), &*variances)
-            })
-            .collect()
+            },
+        ))
     }
 
     fn evaluate(&self, term: VarianceTermPtr<'a>) -> ty::Variance {
diff --git a/compiler/rustc_hir_analysis/src/variance/test.rs b/compiler/rustc_hir_analysis/src/variance/test.rs
index 83ed3e44b3d..5feeb92d337 100644
--- a/compiler/rustc_hir_analysis/src/variance/test.rs
+++ b/compiler/rustc_hir_analysis/src/variance/test.rs
@@ -1,4 +1,3 @@
-use rustc_errors::struct_span_err;
 use rustc_middle::ty::TyCtxt;
 use rustc_span::symbol::sym;
 
@@ -8,8 +7,8 @@ pub fn test_variance(tcx: TyCtxt<'_>) {
     for id in tcx.hir().items() {
         if tcx.has_attr(id.owner_id.to_def_id(), sym::rustc_variance) {
             let variances_of = tcx.variances_of(id.owner_id);
-            struct_span_err!(tcx.sess, tcx.def_span(id.owner_id), E0208, "{:?}", variances_of)
-                .emit();
+
+            tcx.sess.struct_span_err(tcx.def_span(id.owner_id), format!("{variances_of:?}")).emit();
         }
     }
 }
diff --git a/compiler/rustc_hir_typeck/src/callee.rs b/compiler/rustc_hir_typeck/src/callee.rs
index f1a4f94cd01..b617821fbd6 100644
--- a/compiler/rustc_hir_typeck/src/callee.rs
+++ b/compiler/rustc_hir_typeck/src/callee.rs
@@ -375,14 +375,12 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                 if self.tcx.has_attr(def_id, sym::rustc_evaluate_where_clauses) {
                     let predicates = self.tcx.predicates_of(def_id);
                     let predicates = predicates.instantiate(self.tcx, subst);
-                    for (predicate, predicate_span) in
-                        predicates.predicates.iter().zip(&predicates.spans)
-                    {
+                    for (predicate, predicate_span) in predicates {
                         let obligation = Obligation::new(
                             self.tcx,
                             ObligationCause::dummy_with_span(callee_expr.span),
                             self.param_env,
-                            *predicate,
+                            predicate,
                         );
                         let result = self.evaluate_obligation(&obligation);
                         self.tcx
@@ -391,7 +389,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                                 callee_expr.span,
                                 &format!("evaluate({:?}) = {:?}", predicate, result),
                             )
-                            .span_label(*predicate_span, "predicate")
+                            .span_label(predicate_span, "predicate")
                             .emit();
                     }
                 }
diff --git a/compiler/rustc_hir_typeck/src/cast.rs b/compiler/rustc_hir_typeck/src/cast.rs
index 042a50f2fd4..712f9b87aed 100644
--- a/compiler/rustc_hir_typeck/src/cast.rs
+++ b/compiler/rustc_hir_typeck/src/cast.rs
@@ -31,7 +31,10 @@
 use super::FnCtxt;
 
 use crate::type_error_struct;
-use rustc_errors::{struct_span_err, Applicability, DelayDm, DiagnosticBuilder, ErrorGuaranteed};
+use hir::ExprKind;
+use rustc_errors::{
+    struct_span_err, Applicability, DelayDm, Diagnostic, DiagnosticBuilder, ErrorGuaranteed,
+};
 use rustc_hir as hir;
 use rustc_macros::{TypeFoldable, TypeVisitable};
 use rustc_middle::mir::Mutability;
@@ -149,7 +152,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
 #[derive(Copy, Clone)]
 pub enum CastError {
-    ErrorGuaranteed,
+    ErrorGuaranteed(ErrorGuaranteed),
 
     CastToBool,
     CastToChar,
@@ -174,8 +177,8 @@ pub enum CastError {
 }
 
 impl From<ErrorGuaranteed> for CastError {
-    fn from(_: ErrorGuaranteed) -> Self {
-        CastError::ErrorGuaranteed
+    fn from(err: ErrorGuaranteed) -> Self {
+        CastError::ErrorGuaranteed(err)
     }
 }
 
@@ -223,11 +226,10 @@ impl<'a, 'tcx> CastCheck<'tcx> {
 
     fn report_cast_error(&self, fcx: &FnCtxt<'a, 'tcx>, e: CastError) {
         match e {
-            CastError::ErrorGuaranteed => {
+            CastError::ErrorGuaranteed(_) => {
                 // an error has already been reported
             }
             CastError::NeedDeref => {
-                let error_span = self.span;
                 let mut err = make_invalid_casting_error(
                     fcx.tcx.sess,
                     self.span,
@@ -235,21 +237,25 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                     self.cast_ty,
                     fcx,
                 );
-                let cast_ty = fcx.ty_to_string(self.cast_ty);
-                err.span_label(
-                    error_span,
-                    format!("cannot cast `{}` as `{}`", fcx.ty_to_string(self.expr_ty), cast_ty),
-                );
-                if let Ok(snippet) = fcx.sess().source_map().span_to_snippet(self.expr_span) {
-                    err.span_suggestion(
-                        self.expr_span,
-                        "dereference the expression",
-                        format!("*{}", snippet),
-                        Applicability::MaybeIncorrect,
+
+                if matches!(self.expr.kind, ExprKind::AddrOf(..)) {
+                    // get just the borrow part of the expression
+                    let span = self.expr_span.with_hi(self.expr.peel_borrows().span.lo());
+                    err.span_suggestion_verbose(
+                        span,
+                        "remove the unneeded borrow",
+                        "",
+                        Applicability::MachineApplicable,
                     );
                 } else {
-                    err.span_help(self.expr_span, "dereference the expression with `*`");
+                    err.span_suggestion_verbose(
+                        self.expr_span.shrink_to_lo(),
+                        "dereference the expression",
+                        "*",
+                        Applicability::MachineApplicable,
+                    );
                 }
+
                 err.emit();
             }
             CastError::NeedViaThinPtr | CastError::NeedViaPtr => {
@@ -270,6 +276,9 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                         }
                     ));
                 }
+
+                self.try_suggest_collection_to_bool(fcx, &mut err);
+
                 err.emit();
             }
             CastError::NeedViaInt => {
@@ -517,6 +526,9 @@ impl<'a, 'tcx> CastCheck<'tcx> {
                 } else {
                     err.span_label(self.span, "invalid cast");
                 }
+
+                self.try_suggest_collection_to_bool(fcx, &mut err);
+
                 err.emit();
             }
             CastError::SizedUnsizedCast => {
@@ -1080,4 +1092,40 @@ impl<'a, 'tcx> CastCheck<'tcx> {
             },
         );
     }
+
+    /// Attempt to suggest using `.is_empty` when trying to cast from a
+    /// collection type to a boolean.
+    fn try_suggest_collection_to_bool(&self, fcx: &FnCtxt<'a, 'tcx>, err: &mut Diagnostic) {
+        if self.cast_ty.is_bool() {
+            let derefed = fcx
+                .autoderef(self.expr_span, self.expr_ty)
+                .silence_errors()
+                .find(|t| matches!(t.0.kind(), ty::Str | ty::Slice(..)));
+
+            if let Some((deref_ty, _)) = derefed {
+                // Give a note about what the expr derefs to.
+                if deref_ty != self.expr_ty.peel_refs() {
+                    err.span_note(
+                        self.expr_span,
+                        format!(
+                            "this expression `Deref`s to `{}` which implements `is_empty`",
+                            fcx.ty_to_string(deref_ty)
+                        ),
+                    );
+                }
+
+                // Create a multipart suggestion: add `!` and `.is_empty()` in
+                // place of the cast.
+                let suggestion = vec![
+                    (self.expr_span.shrink_to_lo(), "!".to_string()),
+                    (self.span.with_lo(self.expr_span.hi()), ".is_empty()".to_string()),
+                ];
+
+                err.multipart_suggestion_verbose(format!(
+                    "consider using the `is_empty` method on `{}` to determine if it contains anything",
+                    fcx.ty_to_string(self.expr_ty),
+                ),  suggestion, Applicability::MaybeIncorrect);
+            }
+        }
+    }
 }
diff --git a/compiler/rustc_hir_typeck/src/closure.rs b/compiler/rustc_hir_typeck/src/closure.rs
index 26e8dd654c1..12a2abfa76a 100644
--- a/compiler/rustc_hir_typeck/src/closure.rs
+++ b/compiler/rustc_hir_typeck/src/closure.rs
@@ -236,7 +236,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
 
                     fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
                         if t == self.expected_ty {
-                            ControlFlow::BREAK
+                            ControlFlow::Break(())
                         } else {
                             t.super_visit_with(self)
                         }
diff --git a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
index b9e13fd2009..c9609e69439 100644
--- a/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
+++ b/compiler/rustc_hir_typeck/src/fn_ctxt/checks.rs
@@ -2140,8 +2140,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
                         // FIXME(compiler-errors): This could be problematic if something has two
                         // fn-like predicates with different args, but callable types really never
                         // do that, so it's OK.
-                        for (predicate, span) in
-                            std::iter::zip(instantiated.predicates, instantiated.spans)
+                        for (predicate, span) in instantiated
                         {
                             if let ty::PredicateKind::Clause(ty::Clause::Trait(pred)) = predicate.kind().skip_binder()
                                 && pred.self_ty().peel_refs() == callee_ty
diff --git a/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_build.rs b/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_build.rs
index 16806fdba4f..b3dd3031db2 100644
--- a/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_build.rs
+++ b/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_build.rs
@@ -304,8 +304,8 @@ impl<'a, 'tcx> Visitor<'tcx> for DropRangeVisitor<'a, 'tcx> {
         let mut reinit = None;
         match expr.kind {
             ExprKind::Assign(lhs, rhs, _) => {
-                self.visit_expr(lhs);
                 self.visit_expr(rhs);
+                self.visit_expr(lhs);
 
                 reinit = Some(lhs);
             }
@@ -433,7 +433,7 @@ impl<'a, 'tcx> Visitor<'tcx> for DropRangeVisitor<'a, 'tcx> {
                     self.drop_ranges.add_control_edge(self.expr_index, *target)
                 }),
 
-            ExprKind::Break(destination, ..) => {
+            ExprKind::Break(destination, value) => {
                 // destination either points to an expression or to a block. We use
                 // find_target_expression_from_destination to use the last expression of the block
                 // if destination points to a block.
@@ -443,7 +443,11 @@ impl<'a, 'tcx> Visitor<'tcx> for DropRangeVisitor<'a, 'tcx> {
                 // will refer to the end of the block due to the post order traversal.
                 self.find_target_expression_from_destination(destination).map_or((), |target| {
                     self.drop_ranges.add_control_edge_hir_id(self.expr_index, target)
-                })
+                });
+
+                if let Some(value) = value {
+                    self.visit_expr(value);
+                }
             }
 
             ExprKind::Call(f, args) => {
@@ -465,6 +469,12 @@ impl<'a, 'tcx> Visitor<'tcx> for DropRangeVisitor<'a, 'tcx> {
 
             ExprKind::AddrOf(..)
             | ExprKind::Array(..)
+            // FIXME(eholk): We probably need special handling for AssignOps. The ScopeTree builder
+            // in region.rs runs both lhs then rhs and rhs then lhs and then sets all yields to be
+            // the latest they show up in either traversal. With the older scope-based
+            // approximation, this was fine, but it's probably not right now. What we probably want
+            // to do instead is still run both orders, but consider anything that showed up as a
+            // yield in either order.
             | ExprKind::AssignOp(..)
             | ExprKind::Binary(..)
             | ExprKind::Block(..)
@@ -502,6 +512,9 @@ impl<'a, 'tcx> Visitor<'tcx> for DropRangeVisitor<'a, 'tcx> {
 
         // Increment expr_count here to match what InteriorVisitor expects.
         self.expr_index = self.expr_index + 1;
+
+        // Save a node mapping to get better CFG visualization
+        self.drop_ranges.add_node_mapping(pat.hir_id, self.expr_index);
     }
 }
 
@@ -521,7 +534,7 @@ impl DropRangesBuilder {
                 }
             });
         }
-        debug!("hir_id_map: {:?}", tracked_value_map);
+        debug!("hir_id_map: {:#?}", tracked_value_map);
         let num_values = tracked_value_map.len();
         Self {
             tracked_value_map,
diff --git a/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_visualize.rs b/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_visualize.rs
index c0a0bfe8e1c..e8d31be79d9 100644
--- a/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_visualize.rs
+++ b/compiler/rustc_hir_typeck/src/generator_interior/drop_ranges/cfg_visualize.rs
@@ -2,6 +2,7 @@
 //! flow graph when needed for debugging.
 
 use rustc_graphviz as dot;
+use rustc_hir::{Expr, ExprKind, Node};
 use rustc_middle::ty::TyCtxt;
 
 use super::{DropRangesBuilder, PostOrderId};
@@ -80,10 +81,14 @@ impl<'a> dot::Labeller<'a> for DropRangesGraph<'_, '_> {
                     .post_order_map
                     .iter()
                     .find(|(_hir_id, &post_order_id)| post_order_id == *n)
-                    .map_or("<unknown>".into(), |(hir_id, _)| self
-                        .tcx
-                        .hir()
-                        .node_to_string(*hir_id))
+                    .map_or("<unknown>".into(), |(hir_id, _)| format!(
+                        "{}{}",
+                        self.tcx.hir().node_to_string(*hir_id),
+                        match self.tcx.hir().find(*hir_id) {
+                            Some(Node::Expr(Expr { kind: ExprKind::Yield(..), .. })) => " (yield)",
+                            _ => "",
+                        }
+                    ))
             )
             .into(),
         )
diff --git a/compiler/rustc_hir_typeck/src/generator_interior/mod.rs b/compiler/rustc_hir_typeck/src/generator_interior/mod.rs
index 7990d95310b..7af52605385 100644
--- a/compiler/rustc_hir_typeck/src/generator_interior/mod.rs
+++ b/compiler/rustc_hir_typeck/src/generator_interior/mod.rs
@@ -71,10 +71,8 @@ impl<'a, 'tcx> InteriorVisitor<'a, 'tcx> {
                                 yield_data.expr_and_pat_count, self.expr_count, source_span
                             );
 
-                            if self.fcx.sess().opts.unstable_opts.drop_tracking
-                                && self
-                                    .drop_ranges
-                                    .is_dropped_at(hir_id, yield_data.expr_and_pat_count)
+                            if self
+                                .is_dropped_at_yield_location(hir_id, yield_data.expr_and_pat_count)
                             {
                                 debug!("value is dropped at yield point; not recording");
                                 return false;
@@ -173,6 +171,18 @@ impl<'a, 'tcx> InteriorVisitor<'a, 'tcx> {
             }
         }
     }
+
+    /// If drop tracking is enabled, consult drop_ranges to see if a value is
+    /// known to be dropped at a yield point and therefore can be omitted from
+    /// the generator witness.
+    fn is_dropped_at_yield_location(&self, value_hir_id: HirId, yield_location: usize) -> bool {
+        // short-circuit if drop tracking is not enabled.
+        if !self.fcx.sess().opts.unstable_opts.drop_tracking {
+            return false;
+        }
+
+        self.drop_ranges.is_dropped_at(value_hir_id, yield_location)
+    }
 }
 
 pub fn resolve_interior<'a, 'tcx>(
diff --git a/compiler/rustc_hir_typeck/src/intrinsicck.rs b/compiler/rustc_hir_typeck/src/intrinsicck.rs
index c2dc1402465..3c873024c92 100644
--- a/compiler/rustc_hir_typeck/src/intrinsicck.rs
+++ b/compiler/rustc_hir_typeck/src/intrinsicck.rs
@@ -105,6 +105,16 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
         } else {
             err.note(&format!("source type: `{}` ({})", from, skeleton_string(from, sk_from)))
                 .note(&format!("target type: `{}` ({})", to, skeleton_string(to, sk_to)));
+            let mut should_delay_as_bug = false;
+            if let Err(LayoutError::Unknown(bad_from)) = sk_from && bad_from.references_error() {
+                should_delay_as_bug = true;
+            }
+            if let Err(LayoutError::Unknown(bad_to)) = sk_to && bad_to.references_error() {
+                should_delay_as_bug = true;
+            }
+            if should_delay_as_bug {
+                err.delay_as_bug();
+            }
         }
         err.emit();
     }
diff --git a/compiler/rustc_hir_typeck/src/method/confirm.rs b/compiler/rustc_hir_typeck/src/method/confirm.rs
index 4a33a791e1b..372ea30ebd0 100644
--- a/compiler/rustc_hir_typeck/src/method/confirm.rs
+++ b/compiler/rustc_hir_typeck/src/method/confirm.rs
@@ -19,7 +19,6 @@ use rustc_middle::ty::{InternalSubsts, UserSubsts, UserType};
 use rustc_span::{Span, DUMMY_SP};
 use rustc_trait_selection::traits;
 
-use std::iter;
 use std::ops::Deref;
 
 struct ConfirmContext<'a, 'tcx> {
@@ -101,7 +100,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
         let filler_substs = rcvr_substs
             .extend_to(self.tcx, pick.item.def_id, |def, _| self.tcx.mk_param_from_def(def));
         let illegal_sized_bound = self.predicates_require_illegal_sized_bound(
-            &self.tcx.predicates_of(pick.item.def_id).instantiate(self.tcx, filler_substs),
+            self.tcx.predicates_of(pick.item.def_id).instantiate(self.tcx, filler_substs),
         );
 
         // Unify the (adjusted) self type with what the method expects.
@@ -565,7 +564,7 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
 
     fn predicates_require_illegal_sized_bound(
         &self,
-        predicates: &ty::InstantiatedPredicates<'tcx>,
+        predicates: ty::InstantiatedPredicates<'tcx>,
     ) -> Option<Span> {
         let sized_def_id = self.tcx.lang_items().sized_trait()?;
 
@@ -575,10 +574,11 @@ impl<'a, 'tcx> ConfirmContext<'a, 'tcx> {
                 ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred))
                     if trait_pred.def_id() == sized_def_id =>
                 {
-                    let span = iter::zip(&predicates.predicates, &predicates.spans)
+                    let span = predicates
+                        .iter()
                         .find_map(
                             |(p, span)| {
-                                if *p == obligation.predicate { Some(*span) } else { None }
+                                if p == obligation.predicate { Some(span) } else { None }
                             },
                         )
                         .unwrap_or(rustc_span::DUMMY_SP);
diff --git a/compiler/rustc_hir_typeck/src/method/probe.rs b/compiler/rustc_hir_typeck/src/method/probe.rs
index 948a14604d4..a2481431363 100644
--- a/compiler/rustc_hir_typeck/src/method/probe.rs
+++ b/compiler/rustc_hir_typeck/src/method/probe.rs
@@ -486,7 +486,7 @@ impl<'a, 'tcx> FnCtxt<'a, 'tcx> {
             probe_cx.assemble_inherent_candidates();
             match scope {
                 ProbeScope::TraitsInScope => {
-                    probe_cx.assemble_extension_candidates_for_traits_in_scope(scope_expr_id)
+                    probe_cx.assemble_extension_candidates_for_traits_in_scope()
                 }
                 ProbeScope::AllTraits => probe_cx.assemble_extension_candidates_for_all_traits(),
             };
@@ -889,9 +889,9 @@ impl<'a, 'tcx> ProbeContext<'a, 'tcx> {
         }
     }
 
-    fn assemble_extension_candidates_for_traits_in_scope(&mut self, expr_hir_id: hir::HirId) {
+    fn assemble_extension_candidates_for_traits_in_scope(&mut self) {
         let mut duplicates = FxHashSet::default();
-        let opt_applicable_traits = self.tcx.in_scope_traits(expr_hir_id);
+        let opt_applicable_traits = self.tcx.in_scope_traits(self.scope_expr_id);
         if let Some(applicable_traits) = opt_applicable_traits {
             for trait_candidate in applicable_traits.iter() {
                 let trait_did = trait_candidate.def_id;
diff --git a/compiler/rustc_hir_typeck/src/writeback.rs b/compiler/rustc_hir_typeck/src/writeback.rs
index 8c24b600644..250f4cd3f65 100644
--- a/compiler/rustc_hir_typeck/src/writeback.rs
+++ b/compiler/rustc_hir_typeck/src/writeback.rs
@@ -448,8 +448,11 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
         assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
         let common_hir_owner = fcx_typeck_results.hir_owner;
 
-        for (id, origin) in fcx_typeck_results.closure_kind_origins().iter() {
-            let hir_id = hir::HirId { owner: common_hir_owner, local_id: *id };
+        let fcx_closure_kind_origins =
+            fcx_typeck_results.closure_kind_origins().items_in_stable_order();
+
+        for (local_id, origin) in fcx_closure_kind_origins {
+            let hir_id = hir::HirId { owner: common_hir_owner, local_id };
             let place_span = origin.0;
             let place = self.resolve(origin.1.clone(), &place_span);
             self.typeck_results.closure_kind_origins_mut().insert(hir_id, (place_span, place));
@@ -458,11 +461,12 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
 
     fn visit_coercion_casts(&mut self) {
         let fcx_typeck_results = self.fcx.typeck_results.borrow();
-        let fcx_coercion_casts = fcx_typeck_results.coercion_casts();
+
         assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
 
+        let fcx_coercion_casts = fcx_typeck_results.coercion_casts().to_sorted_stable_ord();
         for local_id in fcx_coercion_casts {
-            self.typeck_results.set_coercion_cast(*local_id);
+            self.typeck_results.set_coercion_cast(local_id);
         }
     }
 
@@ -471,22 +475,15 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
         assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
         let common_hir_owner = fcx_typeck_results.hir_owner;
 
-        let mut errors_buffer = Vec::new();
-        for (&local_id, c_ty) in fcx_typeck_results.user_provided_types().iter() {
-            let hir_id = hir::HirId { owner: common_hir_owner, local_id };
-
-            if cfg!(debug_assertions) && c_ty.needs_infer() {
-                span_bug!(
-                    hir_id.to_span(self.fcx.tcx),
-                    "writeback: `{:?}` has inference variables",
-                    c_ty
-                );
-            };
+        if self.rustc_dump_user_substs {
+            let sorted_user_provided_types =
+                fcx_typeck_results.user_provided_types().items_in_stable_order();
 
-            self.typeck_results.user_provided_types_mut().insert(hir_id, *c_ty);
+            let mut errors_buffer = Vec::new();
+            for (local_id, c_ty) in sorted_user_provided_types {
+                let hir_id = hir::HirId { owner: common_hir_owner, local_id };
 
-            if let ty::UserType::TypeOf(_, user_substs) = c_ty.value {
-                if self.rustc_dump_user_substs {
+                if let ty::UserType::TypeOf(_, user_substs) = c_ty.value {
                     // This is a unit-testing mechanism.
                     let span = self.tcx().hir().span(hir_id);
                     // We need to buffer the errors in order to guarantee a consistent
@@ -498,31 +495,49 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
                     err.buffer(&mut errors_buffer);
                 }
             }
-        }
 
-        if !errors_buffer.is_empty() {
-            errors_buffer.sort_by_key(|diag| diag.span.primary_span());
-            for mut diag in errors_buffer {
-                self.tcx().sess.diagnostic().emit_diagnostic(&mut diag);
+            if !errors_buffer.is_empty() {
+                errors_buffer.sort_by_key(|diag| diag.span.primary_span());
+                for mut diag in errors_buffer {
+                    self.tcx().sess.diagnostic().emit_diagnostic(&mut diag);
+                }
             }
         }
+
+        self.typeck_results.user_provided_types_mut().extend(
+            fcx_typeck_results.user_provided_types().items().map(|(local_id, c_ty)| {
+                let hir_id = hir::HirId { owner: common_hir_owner, local_id };
+
+                if cfg!(debug_assertions) && c_ty.needs_infer() {
+                    span_bug!(
+                        hir_id.to_span(self.fcx.tcx),
+                        "writeback: `{:?}` has inference variables",
+                        c_ty
+                    );
+                };
+
+                (hir_id, *c_ty)
+            }),
+        );
     }
 
     fn visit_user_provided_sigs(&mut self) {
         let fcx_typeck_results = self.fcx.typeck_results.borrow();
         assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
 
-        for (&def_id, c_sig) in fcx_typeck_results.user_provided_sigs.iter() {
-            if cfg!(debug_assertions) && c_sig.needs_infer() {
-                span_bug!(
-                    self.fcx.tcx.def_span(def_id),
-                    "writeback: `{:?}` has inference variables",
-                    c_sig
-                );
-            };
-
-            self.typeck_results.user_provided_sigs.insert(def_id, *c_sig);
-        }
+        self.typeck_results.user_provided_sigs.extend(
+            fcx_typeck_results.user_provided_sigs.items().map(|(&def_id, c_sig)| {
+                if cfg!(debug_assertions) && c_sig.needs_infer() {
+                    span_bug!(
+                        self.fcx.tcx.def_span(def_id),
+                        "writeback: `{:?}` has inference variables",
+                        c_sig
+                    );
+                };
+
+                (def_id, *c_sig)
+            }),
+        );
     }
 
     fn visit_generator_interior_types(&mut self) {
@@ -564,7 +579,6 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
                 opaque_type_key,
                 self.fcx.infcx.tcx,
                 true,
-                decl.origin,
             );
 
             self.typeck_results.concrete_opaque_types.insert(opaque_type_key.def_id, hidden_type);
@@ -642,7 +656,9 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
         assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
         let common_hir_owner = fcx_typeck_results.hir_owner;
 
-        for (&local_id, &fn_sig) in fcx_typeck_results.liberated_fn_sigs().iter() {
+        let fcx_liberated_fn_sigs = fcx_typeck_results.liberated_fn_sigs().items_in_stable_order();
+
+        for (local_id, &fn_sig) in fcx_liberated_fn_sigs {
             let hir_id = hir::HirId { owner: common_hir_owner, local_id };
             let fn_sig = self.resolve(fn_sig, &hir_id);
             self.typeck_results.liberated_fn_sigs_mut().insert(hir_id, fn_sig);
@@ -654,7 +670,9 @@ impl<'cx, 'tcx> WritebackCx<'cx, 'tcx> {
         assert_eq!(fcx_typeck_results.hir_owner, self.typeck_results.hir_owner);
         let common_hir_owner = fcx_typeck_results.hir_owner;
 
-        for (&local_id, ftys) in fcx_typeck_results.fru_field_types().iter() {
+        let fcx_fru_field_types = fcx_typeck_results.fru_field_types().items_in_stable_order();
+
+        for (local_id, ftys) in fcx_fru_field_types {
             let hir_id = hir::HirId { owner: common_hir_owner, local_id };
             let ftys = self.resolve(ftys.clone(), &hir_id);
             self.typeck_results.fru_field_types_mut().insert(hir_id, ftys);
diff --git a/compiler/rustc_index/src/vec.rs b/compiler/rustc_index/src/vec.rs
index c18a911b2fb..68cdc6d7711 100644
--- a/compiler/rustc_index/src/vec.rs
+++ b/compiler/rustc_index/src/vec.rs
@@ -207,7 +207,12 @@ impl<I: Idx, T> IndexVec<I, T> {
         &'a mut self,
         range: R,
     ) -> impl Iterator<Item = (I, T)> + 'a {
-        self.raw.drain(range).enumerate().map(|(n, t)| (I::new(n), t))
+        let begin = match range.start_bound() {
+            std::ops::Bound::Included(i) => *i,
+            std::ops::Bound::Excluded(i) => i.checked_add(1).unwrap(),
+            std::ops::Bound::Unbounded => 0,
+        };
+        self.raw.drain(range).enumerate().map(move |(n, t)| (I::new(begin + n), t))
     }
 
     #[inline]
diff --git a/compiler/rustc_infer/src/errors/mod.rs b/compiler/rustc_infer/src/errors/mod.rs
index 033a1842edb..8bf3a160abb 100644
--- a/compiler/rustc_infer/src/errors/mod.rs
+++ b/compiler/rustc_infer/src/errors/mod.rs
@@ -927,6 +927,8 @@ pub struct ButNeedsToSatisfy {
     #[subdiagnostic]
     pub req_introduces_loc: Option<ReqIntroducedLocations>,
 
+    pub has_param_name: bool,
+    pub param_name: String,
     pub spans_empty: bool,
     pub has_lifetime: bool,
     pub lifetime: String,
diff --git a/compiler/rustc_infer/src/infer/error_reporting/mod.rs b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
index abd99fc74da..28fd03b878b 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/mod.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/mod.rs
@@ -2272,10 +2272,10 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
 
         let labeled_user_string = match bound_kind {
             GenericKind::Param(ref p) => format!("the parameter type `{}`", p),
-            GenericKind::Projection(ref p) => format!("the associated type `{}`", p),
-            GenericKind::Opaque(def_id, substs) => {
-                format!("the opaque type `{}`", self.tcx.def_path_str_with_substs(def_id, substs))
-            }
+            GenericKind::Alias(ref p) => match p.kind(self.tcx) {
+                ty::AliasKind::Projection => format!("the associated type `{}`", p),
+                ty::AliasKind::Opaque => format!("the opaque type `{}`", p),
+            },
         };
 
         if let Some(SubregionOrigin::CompareImplItemObligation {
diff --git a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs
index fb0f09198cc..6a463583dfb 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/nice_region_error/static_impl_trait.rs
@@ -98,6 +98,7 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
         let sp = var_origin.span();
         let return_sp = sub_origin.span();
         let param = self.find_param_with_region(*sup_r, *sub_r)?;
+        let simple_ident = param.param.pat.simple_ident();
         let lifetime_name = if sup_r.has_name() { sup_r.to_string() } else { "'_".to_owned() };
 
         let (mention_influencer, influencer_point) =
@@ -187,7 +188,9 @@ impl<'a, 'tcx> NiceRegionError<'a, 'tcx> {
             req_introduces_loc: subdiag,
 
             has_lifetime: sup_r.has_name(),
-            lifetime: sup_r.to_string(),
+            lifetime: lifetime_name.clone(),
+            has_param_name: simple_ident.is_some(),
+            param_name: simple_ident.map(|x| x.to_string()).unwrap_or_default(),
             spans_empty,
             bound,
         };
@@ -543,7 +546,7 @@ impl<'tcx> TypeVisitor<'tcx> for TraitObjectVisitor {
                 if let Some(def_id) = preds.principal_def_id() {
                     self.0.insert(def_id);
                 }
-                ControlFlow::CONTINUE
+                ControlFlow::Continue(())
             }
             _ => t.super_visit_with(self),
         }
diff --git a/compiler/rustc_infer/src/infer/error_reporting/note.rs b/compiler/rustc_infer/src/infer/error_reporting/note.rs
index 021e741ee2f..b18cbd404d4 100644
--- a/compiler/rustc_infer/src/infer/error_reporting/note.rs
+++ b/compiler/rustc_infer/src/infer/error_reporting/note.rs
@@ -330,9 +330,8 @@ impl<'tcx> TypeErrCtxt<'_, 'tcx> {
 
         let Ok(trait_predicates) = self
             .tcx
-            .bound_explicit_predicates_of(trait_item_def_id)
-            .map_bound(|p| p.predicates)
-            .subst_iter_copied(self.tcx, trait_item_substs)
+            .explicit_predicates_of(trait_item_def_id)
+            .instantiate_own(self.tcx, trait_item_substs)
             .map(|(pred, _)| {
                 if pred.is_suggestable(self.tcx, false) {
                     Ok(pred.to_string())
diff --git a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
index 0b478f4cf5c..ce8aec8044b 100644
--- a/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
+++ b/compiler/rustc_infer/src/infer/lexical_region_resolve/mod.rs
@@ -251,7 +251,7 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
                     VarValue::Empty(a_universe) => {
                         let b_data = var_values.value_mut(b_vid);
 
-                        let changed = (|| match *b_data {
+                        let changed = match *b_data {
                             VarValue::Empty(b_universe) => {
                                 // Empty regions are ordered according to the universe
                                 // they are associated with.
@@ -280,20 +280,20 @@ impl<'cx, 'tcx> LexicalResolver<'cx, 'tcx> {
                                 };
 
                                 if lub == cur_region {
-                                    return false;
+                                    false
+                                } else {
+                                    debug!(
+                                        "Expanding value of {:?} from {:?} to {:?}",
+                                        b_vid, cur_region, lub
+                                    );
+
+                                    *b_data = VarValue::Value(lub);
+                                    true
                                 }
-
-                                debug!(
-                                    "Expanding value of {:?} from {:?} to {:?}",
-                                    b_vid, cur_region, lub
-                                );
-
-                                *b_data = VarValue::Value(lub);
-                                true
                             }
 
                             VarValue::ErrorValue => false,
-                        })();
+                        };
 
                         if changed {
                             changes.push(b_vid);
diff --git a/compiler/rustc_infer/src/infer/nll_relate/mod.rs b/compiler/rustc_infer/src/infer/nll_relate/mod.rs
index 985cb6463a0..f235cb5ab45 100644
--- a/compiler/rustc_infer/src/infer/nll_relate/mod.rs
+++ b/compiler/rustc_infer/src/infer/nll_relate/mod.rs
@@ -849,7 +849,7 @@ impl<'me, 'tcx> TypeVisitor<'tcx> for ScopeInstantiator<'me, 'tcx> {
         t.super_visit_with(self);
         self.target_index.shift_out(1);
 
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 
     fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
@@ -863,7 +863,7 @@ impl<'me, 'tcx> TypeVisitor<'tcx> for ScopeInstantiator<'me, 'tcx> {
             _ => {}
         }
 
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
 
diff --git a/compiler/rustc_infer/src/infer/opaque_types.rs b/compiler/rustc_infer/src/infer/opaque_types.rs
index 6b54ee9576f..c54c66eab27 100644
--- a/compiler/rustc_infer/src/infer/opaque_types.rs
+++ b/compiler/rustc_infer/src/infer/opaque_types.rs
@@ -440,16 +440,16 @@ where
         t: &ty::Binder<'tcx, T>,
     ) -> ControlFlow<Self::BreakTy> {
         t.super_visit_with(self);
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 
     fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
         match *r {
             // ignore bound regions, keep visiting
-            ty::ReLateBound(_, _) => ControlFlow::CONTINUE,
+            ty::ReLateBound(_, _) => ControlFlow::Continue(()),
             _ => {
                 (self.op)(r);
-                ControlFlow::CONTINUE
+                ControlFlow::Continue(())
             }
         }
     }
@@ -457,7 +457,7 @@ where
     fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
         // We're only interested in types involving regions
         if !ty.flags().intersects(ty::TypeFlags::HAS_FREE_REGIONS) {
-            return ControlFlow::CONTINUE;
+            return ControlFlow::Continue(());
         }
 
         match ty.kind() {
@@ -479,7 +479,7 @@ where
             }
 
             ty::Alias(ty::Opaque, ty::AliasTy { def_id, ref substs, .. }) => {
-                // Skip lifetime paramters that are not captures.
+                // Skip lifetime parameters that are not captures.
                 let variances = self.tcx.variances_of(*def_id);
 
                 for (v, s) in std::iter::zip(variances, substs.iter()) {
@@ -492,7 +492,7 @@ where
             ty::Alias(ty::Projection, proj)
                 if self.tcx.def_kind(proj.def_id) == DefKind::ImplTraitPlaceholder =>
             {
-                // Skip lifetime paramters that are not captures.
+                // Skip lifetime parameters that are not captures.
                 let variances = self.tcx.variances_of(proj.def_id);
 
                 for (v, s) in std::iter::zip(variances, proj.substs.iter()) {
@@ -507,7 +507,7 @@ where
             }
         }
 
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
 
diff --git a/compiler/rustc_infer/src/infer/outlives/components.rs b/compiler/rustc_infer/src/infer/outlives/components.rs
index 31d978b4ccb..3d86279b03c 100644
--- a/compiler/rustc_infer/src/infer/outlives/components.rs
+++ b/compiler/rustc_infer/src/infer/outlives/components.rs
@@ -3,9 +3,8 @@
 // RFC for reference.
 
 use rustc_data_structures::sso::SsoHashSet;
-use rustc_hir::def_id::DefId;
 use rustc_middle::ty::subst::{GenericArg, GenericArgKind};
-use rustc_middle::ty::{self, SubstsRef, Ty, TyCtxt, TypeVisitable};
+use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable};
 use smallvec::{smallvec, SmallVec};
 
 #[derive(Debug)]
@@ -23,7 +22,7 @@ pub enum Component<'tcx> {
     // is not in a position to judge which is the best technique, so
     // we just product the projection as a component and leave it to
     // the consumer to decide (but see `EscapingProjection` below).
-    Projection(ty::AliasTy<'tcx>),
+    Alias(ty::AliasTy<'tcx>),
 
     // In the case where a projection has escaping regions -- meaning
     // regions bound within the type itself -- we always use
@@ -45,9 +44,7 @@ pub enum Component<'tcx> {
     // projection, so that implied bounds code can avoid relying on
     // them. This gives us room to improve the regionck reasoning in
     // the future without breaking backwards compat.
-    EscapingProjection(Vec<Component<'tcx>>),
-
-    Opaque(DefId, SubstsRef<'tcx>),
+    EscapingAlias(Vec<Component<'tcx>>),
 }
 
 /// Push onto `out` all the things that must outlive `'a` for the condition
@@ -123,17 +120,6 @@ fn compute_components<'tcx>(
                 out.push(Component::Param(p));
             }
 
-            // Ignore lifetimes found in opaque types. Opaque types can
-            // have lifetimes in their substs which their hidden type doesn't
-            // actually use. If we inferred that an opaque type is outlived by
-            // its parameter lifetimes, then we could prove that any lifetime
-            // outlives any other lifetime, which is unsound.
-            // See https://github.com/rust-lang/rust/issues/84305 for
-            // more details.
-            ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
-                out.push(Component::Opaque(def_id, substs));
-            },
-
             // For projections, we prefer to generate an obligation like
             // `<P0 as Trait<P1...Pn>>::Foo: 'a`, because this gives the
             // regionck more ways to prove that it holds. However,
@@ -142,15 +128,15 @@ fn compute_components<'tcx>(
             // trait-ref. Therefore, if we see any higher-ranked regions,
             // we simply fallback to the most restrictive rule, which
             // requires that `Pi: 'a` for all `i`.
-            ty::Alias(ty::Projection, ref data) => {
-                if !data.has_escaping_bound_vars() {
+            ty::Alias(_, alias_ty) => {
+                if !alias_ty.has_escaping_bound_vars() {
                     // best case: no escaping regions, so push the
                     // projection and skip the subtree (thus generating no
                     // constraints for Pi). This defers the choice between
                     // the rules OutlivesProjectionEnv,
                     // OutlivesProjectionTraitDef, and
                     // OutlivesProjectionComponents to regionck.
-                    out.push(Component::Projection(*data));
+                    out.push(Component::Alias(alias_ty));
                 } else {
                     // fallback case: hard code
                     // OutlivesProjectionComponents. Continue walking
@@ -158,7 +144,7 @@ fn compute_components<'tcx>(
                     let mut subcomponents = smallvec![];
                     let mut subvisited = SsoHashSet::new();
                     compute_components_recursive(tcx, ty.into(), &mut subcomponents, &mut subvisited);
-                    out.push(Component::EscapingProjection(subcomponents.into_iter().collect()));
+                    out.push(Component::EscapingAlias(subcomponents.into_iter().collect()));
                 }
             }
 
diff --git a/compiler/rustc_infer/src/infer/outlives/env.rs b/compiler/rustc_infer/src/infer/outlives/env.rs
index 33543135ddb..24e3c34dd94 100644
--- a/compiler/rustc_infer/src/infer/outlives/env.rs
+++ b/compiler/rustc_infer/src/infer/outlives/env.rs
@@ -138,13 +138,9 @@ impl<'tcx> OutlivesEnvironmentBuilder<'tcx> {
                     self.region_bound_pairs
                         .insert(ty::OutlivesPredicate(GenericKind::Param(param_b), r_a));
                 }
-                OutlivesBound::RegionSubProjection(r_a, projection_b) => {
+                OutlivesBound::RegionSubAlias(r_a, alias_b) => {
                     self.region_bound_pairs
-                        .insert(ty::OutlivesPredicate(GenericKind::Projection(projection_b), r_a));
-                }
-                OutlivesBound::RegionSubOpaque(r_a, def_id, substs) => {
-                    self.region_bound_pairs
-                        .insert(ty::OutlivesPredicate(GenericKind::Opaque(def_id, substs), r_a));
+                        .insert(ty::OutlivesPredicate(GenericKind::Alias(alias_b), r_a));
                 }
                 OutlivesBound::RegionSubRegion(r_a, r_b) => {
                     if let (ReEarlyBound(_) | ReFree(_), ReVar(vid_b)) = (r_a.kind(), r_b.kind()) {
diff --git a/compiler/rustc_infer/src/infer/outlives/obligations.rs b/compiler/rustc_infer/src/infer/outlives/obligations.rs
index 07838911c88..0194549a886 100644
--- a/compiler/rustc_infer/src/infer/outlives/obligations.rs
+++ b/compiler/rustc_infer/src/infer/outlives/obligations.rs
@@ -67,7 +67,6 @@ use crate::infer::{
 };
 use crate::traits::{ObligationCause, ObligationCauseCode};
 use rustc_data_structures::undo_log::UndoLogs;
-use rustc_hir::def_id::DefId;
 use rustc_middle::mir::ConstraintCategory;
 use rustc_middle::ty::subst::GenericArgKind;
 use rustc_middle::ty::{self, Region, SubstsRef, Ty, TyCtxt, TypeVisitable};
@@ -266,13 +265,8 @@ where
                 Component::Param(param_ty) => {
                     self.param_ty_must_outlive(origin, region, *param_ty);
                 }
-                Component::Opaque(def_id, substs) => {
-                    self.opaque_must_outlive(*def_id, substs, origin, region)
-                }
-                Component::Projection(projection_ty) => {
-                    self.projection_must_outlive(origin, region, *projection_ty);
-                }
-                Component::EscapingProjection(subcomponents) => {
+                Component::Alias(alias_ty) => self.alias_ty_must_outlive(origin, region, *alias_ty),
+                Component::EscapingAlias(subcomponents) => {
                     self.components_must_outlive(origin, &subcomponents, region, category);
                 }
                 Component::UnresolvedInferenceVariable(v) => {
@@ -288,80 +282,26 @@ where
         }
     }
 
+    #[instrument(level = "debug", skip(self))]
     fn param_ty_must_outlive(
         &mut self,
         origin: infer::SubregionOrigin<'tcx>,
         region: ty::Region<'tcx>,
         param_ty: ty::ParamTy,
     ) {
-        debug!(
-            "param_ty_must_outlive(region={:?}, param_ty={:?}, origin={:?})",
-            region, param_ty, origin
-        );
-
-        let generic = GenericKind::Param(param_ty);
         let verify_bound = self.verify_bound.param_bound(param_ty);
-        self.delegate.push_verify(origin, generic, region, verify_bound);
-    }
-
-    #[instrument(level = "debug", skip(self))]
-    fn opaque_must_outlive(
-        &mut self,
-        def_id: DefId,
-        substs: SubstsRef<'tcx>,
-        origin: infer::SubregionOrigin<'tcx>,
-        region: ty::Region<'tcx>,
-    ) {
-        self.generic_must_outlive(
-            origin,
-            region,
-            GenericKind::Opaque(def_id, substs),
-            def_id,
-            substs,
-            true,
-            |ty| match *ty.kind() {
-                ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => (def_id, substs),
-                _ => bug!("expected only projection types from env, not {:?}", ty),
-            },
-        );
+        self.delegate.push_verify(origin, GenericKind::Param(param_ty), region, verify_bound);
     }
 
     #[instrument(level = "debug", skip(self))]
-    fn projection_must_outlive(
+    fn alias_ty_must_outlive(
         &mut self,
         origin: infer::SubregionOrigin<'tcx>,
         region: ty::Region<'tcx>,
-        projection_ty: ty::AliasTy<'tcx>,
-    ) {
-        self.generic_must_outlive(
-            origin,
-            region,
-            GenericKind::Projection(projection_ty),
-            projection_ty.def_id,
-            projection_ty.substs,
-            false,
-            |ty| match ty.kind() {
-                ty::Alias(ty::Projection, projection_ty) => {
-                    (projection_ty.def_id, projection_ty.substs)
-                }
-                _ => bug!("expected only projection types from env, not {:?}", ty),
-            },
-        );
-    }
-
-    #[instrument(level = "debug", skip(self, filter))]
-    fn generic_must_outlive(
-        &mut self,
-        origin: infer::SubregionOrigin<'tcx>,
-        region: ty::Region<'tcx>,
-        generic: GenericKind<'tcx>,
-        def_id: DefId,
-        substs: SubstsRef<'tcx>,
-        is_opaque: bool,
-        filter: impl Fn(Ty<'tcx>) -> (DefId, SubstsRef<'tcx>),
+        alias_ty: ty::AliasTy<'tcx>,
     ) {
         // An optimization for a common case with opaque types.
-        if substs.is_empty() {
+        if alias_ty.substs.is_empty() {
             return;
         }
 
@@ -383,14 +323,14 @@ where
         // These are guaranteed to apply, no matter the inference
         // results.
         let trait_bounds: Vec<_> =
-            self.verify_bound.declared_region_bounds(def_id, substs).collect();
+            self.verify_bound.declared_bounds_from_definition(alias_ty).collect();
 
         debug!(?trait_bounds);
 
         // Compute the bounds we can derive from the environment. This
         // is an "approximate" match -- in some cases, these bounds
         // may not apply.
-        let mut approx_env_bounds = self.verify_bound.approx_declared_bounds_from_env(generic);
+        let mut approx_env_bounds = self.verify_bound.approx_declared_bounds_from_env(alias_ty);
         debug!(?approx_env_bounds);
 
         // Remove outlives bounds that we get from the environment but
@@ -405,8 +345,8 @@ where
             // If the declaration is `trait Trait<'b> { type Item: 'b; }`, then `projection_declared_bounds_from_trait`
             // will be invoked with `['b => ^1]` and so we will get `^1` returned.
             let bound = bound_outlives.skip_binder();
-            let (def_id, substs) = filter(bound.0);
-            self.verify_bound.declared_region_bounds(def_id, substs).all(|r| r != bound.1)
+            let ty::Alias(_, alias_ty) = bound.0.kind() else { bug!("expected AliasTy") };
+            self.verify_bound.declared_bounds_from_definition(*alias_ty).all(|r| r != bound.1)
         });
 
         // If declared bounds list is empty, the only applicable rule is
@@ -423,12 +363,12 @@ where
         // the problem is to add `T: 'r`, which isn't true. So, if there are no
         // inference variables, we use a verify constraint instead of adding
         // edges, which winds up enforcing the same condition.
-        let needs_infer = substs.needs_infer();
-        if approx_env_bounds.is_empty() && trait_bounds.is_empty() && (needs_infer || is_opaque) {
+        if approx_env_bounds.is_empty()
+            && trait_bounds.is_empty()
+            && (alias_ty.needs_infer() || alias_ty.kind(self.tcx) == ty::Opaque)
+        {
             debug!("no declared bounds");
-
-            self.substs_must_outlive(substs, origin, region);
-
+            self.substs_must_outlive(alias_ty.substs, origin, region);
             return;
         }
 
@@ -469,14 +409,9 @@ where
         // projection outlive; in some cases, this may add insufficient
         // edges into the inference graph, leading to inference failures
         // even though a satisfactory solution exists.
-        let verify_bound = self.verify_bound.projection_opaque_bounds(
-            generic,
-            def_id,
-            substs,
-            &mut Default::default(),
-        );
-        debug!("projection_must_outlive: pushing {:?}", verify_bound);
-        self.delegate.push_verify(origin, generic, region, verify_bound);
+        let verify_bound = self.verify_bound.alias_bound(alias_ty, &mut Default::default());
+        debug!("alias_must_outlive: pushing {:?}", verify_bound);
+        self.delegate.push_verify(origin, GenericKind::Alias(alias_ty), region, verify_bound);
     }
 
     fn substs_must_outlive(
diff --git a/compiler/rustc_infer/src/infer/outlives/verify.rs b/compiler/rustc_infer/src/infer/outlives/verify.rs
index 40bbec8ddd0..94de9bc2d02 100644
--- a/compiler/rustc_infer/src/infer/outlives/verify.rs
+++ b/compiler/rustc_infer/src/infer/outlives/verify.rs
@@ -1,11 +1,10 @@
 use crate::infer::outlives::components::{compute_components_recursive, Component};
 use crate::infer::outlives::env::RegionBoundPairs;
 use crate::infer::region_constraints::VerifyIfEq;
-use crate::infer::{GenericKind, VerifyBound};
+use crate::infer::VerifyBound;
 use rustc_data_structures::sso::SsoHashSet;
-use rustc_hir::def_id::DefId;
 use rustc_middle::ty::GenericArg;
-use rustc_middle::ty::{self, OutlivesPredicate, SubstsRef, Ty, TyCtxt};
+use rustc_middle::ty::{self, OutlivesPredicate, Ty, TyCtxt};
 
 use smallvec::smallvec;
 
@@ -94,29 +93,26 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
     /// this list.
     pub fn approx_declared_bounds_from_env(
         &self,
-        generic: GenericKind<'tcx>,
+        alias_ty: ty::AliasTy<'tcx>,
     ) -> Vec<ty::Binder<'tcx, ty::OutlivesPredicate<Ty<'tcx>, ty::Region<'tcx>>>> {
-        let projection_ty = generic.to_ty(self.tcx);
-        let erased_projection_ty = self.tcx.erase_regions(projection_ty);
-        self.declared_generic_bounds_from_env_for_erased_ty(erased_projection_ty)
+        let erased_alias_ty = self.tcx.erase_regions(alias_ty.to_ty(self.tcx));
+        self.declared_generic_bounds_from_env_for_erased_ty(erased_alias_ty)
     }
 
     #[instrument(level = "debug", skip(self, visited))]
-    pub fn projection_opaque_bounds(
+    pub fn alias_bound(
         &self,
-        generic: GenericKind<'tcx>,
-        def_id: DefId,
-        substs: SubstsRef<'tcx>,
+        alias_ty: ty::AliasTy<'tcx>,
         visited: &mut SsoHashSet<GenericArg<'tcx>>,
     ) -> VerifyBound<'tcx> {
-        let generic_ty = generic.to_ty(self.tcx);
+        let alias_ty_as_ty = alias_ty.to_ty(self.tcx);
 
         // Search the env for where clauses like `P: 'a`.
-        let projection_opaque_bounds = self
-            .approx_declared_bounds_from_env(generic)
+        let env_bounds = self
+            .approx_declared_bounds_from_env(alias_ty)
             .into_iter()
             .map(|binder| {
-                if let Some(ty::OutlivesPredicate(ty, r)) = binder.no_bound_vars() && ty == generic_ty {
+                if let Some(ty::OutlivesPredicate(ty, r)) = binder.no_bound_vars() && ty == alias_ty_as_ty {
                     // Micro-optimize if this is an exact match (this
                     // occurs often when there are no region variables
                     // involved).
@@ -126,19 +122,19 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
                     VerifyBound::IfEq(verify_if_eq_b)
                 }
             });
-        // Extend with bounds that we can find from the trait.
-        let trait_bounds =
-            self.declared_region_bounds(def_id, substs).map(|r| VerifyBound::OutlivedBy(r));
+
+        // Extend with bounds that we can find from the definition.
+        let definition_bounds =
+            self.declared_bounds_from_definition(alias_ty).map(|r| VerifyBound::OutlivedBy(r));
 
         // see the extensive comment in projection_must_outlive
         let recursive_bound = {
             let mut components = smallvec![];
-            compute_components_recursive(self.tcx, generic_ty.into(), &mut components, visited);
+            compute_components_recursive(self.tcx, alias_ty_as_ty.into(), &mut components, visited);
             self.bound_from_components(&components, visited)
         };
 
-        VerifyBound::AnyBound(projection_opaque_bounds.chain(trait_bounds).collect())
-            .or(recursive_bound)
+        VerifyBound::AnyBound(env_bounds.chain(definition_bounds).collect()).or(recursive_bound)
     }
 
     fn bound_from_components(
@@ -149,10 +145,8 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
         let mut bounds = components
             .iter()
             .map(|component| self.bound_from_single_component(component, visited))
-            .filter(|bound| {
-                // Remove bounds that must hold, since they are not interesting.
-                !bound.must_hold()
-            });
+            // Remove bounds that must hold, since they are not interesting.
+            .filter(|bound| !bound.must_hold());
 
         match (bounds.next(), bounds.next()) {
             (Some(first), None) => first,
@@ -170,19 +164,8 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
         match *component {
             Component::Region(lt) => VerifyBound::OutlivedBy(lt),
             Component::Param(param_ty) => self.param_bound(param_ty),
-            Component::Opaque(did, substs) => self.projection_opaque_bounds(
-                GenericKind::Opaque(did, substs),
-                did,
-                substs,
-                visited,
-            ),
-            Component::Projection(projection_ty) => self.projection_opaque_bounds(
-                GenericKind::Projection(projection_ty),
-                projection_ty.def_id,
-                projection_ty.substs,
-                visited,
-            ),
-            Component::EscapingProjection(ref components) => {
+            Component::Alias(alias_ty) => self.alias_bound(alias_ty, visited),
+            Component::EscapingAlias(ref components) => {
                 self.bound_from_components(components, visited)
             }
             Component::UnresolvedInferenceVariable(v) => {
@@ -298,16 +281,15 @@ impl<'cx, 'tcx> VerifyBoundCx<'cx, 'tcx> {
     ///
     /// This is for simplicity, and because we are not really smart
     /// enough to cope with such bounds anywhere.
-    pub fn declared_region_bounds(
+    pub fn declared_bounds_from_definition(
         &self,
-        def_id: DefId,
-        substs: SubstsRef<'tcx>,
+        alias_ty: ty::AliasTy<'tcx>,
     ) -> impl Iterator<Item = ty::Region<'tcx>> {
         let tcx = self.tcx;
-        let bounds = tcx.bound_item_bounds(def_id);
+        let bounds = tcx.item_bounds(alias_ty.def_id);
         trace!("{:#?}", bounds.0);
         bounds
-            .subst_iter(tcx, substs)
+            .subst_iter(tcx, alias_ty.substs)
             .filter_map(|p| p.to_opt_type_outlives())
             .filter_map(|p| p.no_bound_vars())
             .map(|OutlivesPredicate(_, r)| r)
diff --git a/compiler/rustc_infer/src/infer/region_constraints/mod.rs b/compiler/rustc_infer/src/infer/region_constraints/mod.rs
index 9a427ceacd0..0428481b7ff 100644
--- a/compiler/rustc_infer/src/infer/region_constraints/mod.rs
+++ b/compiler/rustc_infer/src/infer/region_constraints/mod.rs
@@ -12,10 +12,8 @@ use rustc_data_structures::intern::Interned;
 use rustc_data_structures::sync::Lrc;
 use rustc_data_structures::undo_log::UndoLogs;
 use rustc_data_structures::unify as ut;
-use rustc_hir::def_id::DefId;
 use rustc_index::vec::IndexVec;
 use rustc_middle::infer::unify_key::{RegionVidKey, UnifiedRegion};
-use rustc_middle::ty::subst::SubstsRef;
 use rustc_middle::ty::ReStatic;
 use rustc_middle::ty::{self, Ty, TyCtxt};
 use rustc_middle::ty::{ReLateBound, ReVar};
@@ -169,8 +167,7 @@ pub struct Verify<'tcx> {
 #[derive(Copy, Clone, PartialEq, Eq, Hash, TypeFoldable, TypeVisitable)]
 pub enum GenericKind<'tcx> {
     Param(ty::ParamTy),
-    Projection(ty::AliasTy<'tcx>),
-    Opaque(DefId, SubstsRef<'tcx>),
+    Alias(ty::AliasTy<'tcx>),
 }
 
 /// Describes the things that some `GenericKind` value `G` is known to
@@ -749,10 +746,7 @@ impl<'tcx> fmt::Debug for GenericKind<'tcx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             GenericKind::Param(ref p) => write!(f, "{:?}", p),
-            GenericKind::Projection(ref p) => write!(f, "{:?}", p),
-            GenericKind::Opaque(def_id, substs) => ty::tls::with(|tcx| {
-                write!(f, "{}", tcx.def_path_str_with_substs(def_id, tcx.lift(substs).unwrap()))
-            }),
+            GenericKind::Alias(ref p) => write!(f, "{:?}", p),
         }
     }
 }
@@ -761,10 +755,7 @@ impl<'tcx> fmt::Display for GenericKind<'tcx> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         match *self {
             GenericKind::Param(ref p) => write!(f, "{}", p),
-            GenericKind::Projection(ref p) => write!(f, "{}", p),
-            GenericKind::Opaque(def_id, substs) => ty::tls::with(|tcx| {
-                write!(f, "{}", tcx.def_path_str_with_substs(def_id, tcx.lift(substs).unwrap()))
-            }),
+            GenericKind::Alias(ref p) => write!(f, "{}", p),
         }
     }
 }
@@ -773,8 +764,7 @@ impl<'tcx> GenericKind<'tcx> {
     pub fn to_ty(&self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
         match *self {
             GenericKind::Param(ref p) => p.to_ty(tcx),
-            GenericKind::Projection(ref p) => tcx.mk_projection(p.def_id, p.substs),
-            GenericKind::Opaque(def_id, substs) => tcx.mk_opaque(def_id, substs),
+            GenericKind::Alias(ref p) => p.to_ty(tcx),
         }
     }
 }
diff --git a/compiler/rustc_infer/src/infer/resolve.rs b/compiler/rustc_infer/src/infer/resolve.rs
index 8671f8d45a9..65b90aa3d79 100644
--- a/compiler/rustc_infer/src/infer/resolve.rs
+++ b/compiler/rustc_infer/src/infer/resolve.rs
@@ -147,7 +147,7 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for UnresolvedTypeOrConstFinder<'a, 'tcx> {
         } else if !t.has_non_region_infer() {
             // All const/type variables in inference types must already be resolved,
             // no need to visit the contents.
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         } else {
             // Otherwise, keep visiting.
             t.super_visit_with(self)
@@ -178,7 +178,7 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for UnresolvedTypeOrConstFinder<'a, 'tcx> {
         } else if !ct.has_non_region_infer() {
             // All const/type variables in inference types must already be resolved,
             // no need to visit the contents.
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         } else {
             // Otherwise, keep visiting.
             ct.super_visit_with(self)
diff --git a/compiler/rustc_infer/src/traits/util.rs b/compiler/rustc_infer/src/traits/util.rs
index bad07561811..cd5bde2a791 100644
--- a/compiler/rustc_infer/src/traits/util.rs
+++ b/compiler/rustc_infer/src/traits/util.rs
@@ -261,23 +261,15 @@ impl<'tcx> Elaborator<'tcx> {
 
                             Component::UnresolvedInferenceVariable(_) => None,
 
-                            Component::Opaque(def_id, substs) => {
-                                let ty = tcx.mk_opaque(def_id, substs);
-                                Some(ty::PredicateKind::Clause(ty::Clause::TypeOutlives(
-                                    ty::OutlivesPredicate(ty, r_min),
-                                )))
-                            }
-
-                            Component::Projection(projection) => {
+                            Component::Alias(alias_ty) => {
                                 // We might end up here if we have `Foo<<Bar as Baz>::Assoc>: 'a`.
                                 // With this, we can deduce that `<Bar as Baz>::Assoc: 'a`.
-                                let ty = tcx.mk_projection(projection.def_id, projection.substs);
                                 Some(ty::PredicateKind::Clause(ty::Clause::TypeOutlives(
-                                    ty::OutlivesPredicate(ty, r_min),
+                                    ty::OutlivesPredicate(alias_ty.to_ty(tcx), r_min),
                                 )))
                             }
 
-                            Component::EscapingProjection(_) => {
+                            Component::EscapingAlias(_) => {
                                 // We might be able to do more here, but we don't
                                 // want to deal with escaping vars right now.
                                 None
diff --git a/compiler/rustc_interface/src/interface.rs b/compiler/rustc_interface/src/interface.rs
index 7f761b005ed..7a5e45ada3f 100644
--- a/compiler/rustc_interface/src/interface.rs
+++ b/compiler/rustc_interface/src/interface.rs
@@ -14,10 +14,10 @@ use rustc_middle::ty;
 use rustc_parse::maybe_new_parser_from_source_str;
 use rustc_query_impl::QueryCtxt;
 use rustc_session::config::{self, CheckCfg, ErrorOutputType, Input, OutputFilenames};
-use rustc_session::early_error;
 use rustc_session::lint;
 use rustc_session::parse::{CrateConfig, ParseSess};
 use rustc_session::Session;
+use rustc_session::{early_error, CompilerIO};
 use rustc_span::source_map::{FileLoader, FileName};
 use rustc_span::symbol::sym;
 use std::path::PathBuf;
@@ -35,11 +35,6 @@ pub type Result<T> = result::Result<T, ErrorGuaranteed>;
 pub struct Compiler {
     pub(crate) sess: Lrc<Session>,
     codegen_backend: Lrc<Box<dyn CodegenBackend>>,
-    pub(crate) input: Input,
-    pub(crate) input_path: Option<PathBuf>,
-    pub(crate) output_dir: Option<PathBuf>,
-    pub(crate) output_file: Option<PathBuf>,
-    pub(crate) temps_dir: Option<PathBuf>,
     pub(crate) register_lints: Option<Box<dyn Fn(&Session, &mut LintStore) + Send + Sync>>,
     pub(crate) override_queries:
         Option<fn(&Session, &mut ty::query::Providers, &mut ty::query::ExternProviders)>,
@@ -52,18 +47,6 @@ impl Compiler {
     pub fn codegen_backend(&self) -> &Lrc<Box<dyn CodegenBackend>> {
         &self.codegen_backend
     }
-    pub fn input(&self) -> &Input {
-        &self.input
-    }
-    pub fn output_dir(&self) -> &Option<PathBuf> {
-        &self.output_dir
-    }
-    pub fn output_file(&self) -> &Option<PathBuf> {
-        &self.output_file
-    }
-    pub fn temps_dir(&self) -> &Option<PathBuf> {
-        &self.temps_dir
-    }
     pub fn register_lints(&self) -> &Option<Box<dyn Fn(&Session, &mut LintStore) + Send + Sync>> {
         &self.register_lints
     }
@@ -72,14 +55,7 @@ impl Compiler {
         sess: &Session,
         attrs: &[ast::Attribute],
     ) -> OutputFilenames {
-        util::build_output_filenames(
-            &self.input,
-            &self.output_dir,
-            &self.output_file,
-            &self.temps_dir,
-            attrs,
-            sess,
-        )
+        util::build_output_filenames(attrs, sess)
     }
 }
 
@@ -244,7 +220,6 @@ pub struct Config {
     pub crate_check_cfg: CheckCfg,
 
     pub input: Input,
-    pub input_path: Option<PathBuf>,
     pub output_dir: Option<PathBuf>,
     pub output_file: Option<PathBuf>,
     pub file_loader: Option<Box<dyn FileLoader + Send + Sync>>,
@@ -287,12 +262,19 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
             crate::callbacks::setup_callbacks();
 
             let registry = &config.registry;
+
+            let temps_dir = config.opts.unstable_opts.temps_dir.as_deref().map(PathBuf::from);
             let (mut sess, codegen_backend) = util::create_session(
                 config.opts,
                 config.crate_cfg,
                 config.crate_check_cfg,
                 config.file_loader,
-                config.input_path.clone(),
+                CompilerIO {
+                    input: config.input,
+                    output_dir: config.output_dir,
+                    output_file: config.output_file,
+                    temps_dir,
+                },
                 config.lint_caps,
                 config.make_codegen_backend,
                 registry.clone(),
@@ -302,16 +284,9 @@ pub fn run_compiler<R: Send>(config: Config, f: impl FnOnce(&Compiler) -> R + Se
                 parse_sess_created(&mut sess.parse_sess);
             }
 
-            let temps_dir = sess.opts.unstable_opts.temps_dir.as_deref().map(PathBuf::from);
-
             let compiler = Compiler {
                 sess: Lrc::new(sess),
                 codegen_backend: Lrc::new(codegen_backend),
-                input: config.input,
-                input_path: config.input_path,
-                output_dir: config.output_dir,
-                output_file: config.output_file,
-                temps_dir,
                 register_lints: config.register_lints,
                 override_queries: config.override_queries,
             };
diff --git a/compiler/rustc_interface/src/lib.rs b/compiler/rustc_interface/src/lib.rs
index 542b638bbd7..82bc4770b6b 100644
--- a/compiler/rustc_interface/src/lib.rs
+++ b/compiler/rustc_interface/src/lib.rs
@@ -3,6 +3,7 @@
 #![feature(internal_output_capture)]
 #![feature(thread_spawn_unchecked)]
 #![feature(once_cell)]
+#![feature(try_blocks)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]
diff --git a/compiler/rustc_interface/src/passes.rs b/compiler/rustc_interface/src/passes.rs
index 50c40206d80..379a76528f3 100644
--- a/compiler/rustc_interface/src/passes.rs
+++ b/compiler/rustc_interface/src/passes.rs
@@ -13,7 +13,6 @@ use rustc_ast::{self as ast, visit};
 use rustc_borrowck as mir_borrowck;
 use rustc_codegen_ssa::traits::CodegenBackend;
 use rustc_data_structures::parallel;
-use rustc_data_structures::steal::Steal;
 use rustc_data_structures::sync::{Lrc, OnceCell, WorkerLocal};
 use rustc_errors::{ErrorGuaranteed, PResult};
 use rustc_expand::base::{ExtCtxt, LintStoreExpand, ResolverExpand};
@@ -31,7 +30,7 @@ use rustc_plugin_impl as plugin;
 use rustc_query_impl::{OnDiskCache, Queries as TcxQueries};
 use rustc_resolve::{Resolver, ResolverArenas};
 use rustc_session::config::{CrateType, Input, OutputFilenames, OutputType};
-use rustc_session::cstore::{MetadataLoader, MetadataLoaderDyn};
+use rustc_session::cstore::{MetadataLoader, MetadataLoaderDyn, Untracked};
 use rustc_session::output::filename_for_input;
 use rustc_session::search_paths::PathKind;
 use rustc_session::{Limit, Session};
@@ -51,8 +50,8 @@ use std::rc::Rc;
 use std::sync::LazyLock;
 use std::{env, fs, iter};
 
-pub fn parse<'a>(sess: &'a Session, input: &Input) -> PResult<'a, ast::Crate> {
-    let krate = sess.time("parse_crate", || match input {
+pub fn parse<'a>(sess: &'a Session) -> PResult<'a, ast::Crate> {
+    let krate = sess.time("parse_crate", || match &sess.io.input {
         Input::File(file) => parse_crate_from_file(file, &sess.parse_sess),
         Input::Str { input, name } => {
             parse_crate_from_source_str(name.clone(), input.clone(), &sess.parse_sess)
@@ -559,7 +558,7 @@ fn write_out_deps(
     }
     let deps_filename = outputs.path(OutputType::DepInfo);
 
-    let result = (|| -> io::Result<()> {
+    let result: io::Result<()> = try {
         // Build a list of files used to compile the output and
         // write Makefile-compatible dependency rules
         let mut files: Vec<String> = sess
@@ -646,9 +645,7 @@ fn write_out_deps(
                 writeln!(file)?;
             }
         }
-
-        Ok(())
-    })();
+    };
 
     match result {
         Ok(_) => {
@@ -666,7 +663,6 @@ fn write_out_deps(
 
 pub fn prepare_outputs(
     sess: &Session,
-    compiler: &Compiler,
     krate: &ast::Crate,
     boxed_resolver: &RefCell<BoxedResolver>,
     crate_name: Symbol,
@@ -674,20 +670,13 @@ pub fn prepare_outputs(
     let _timer = sess.timer("prepare_outputs");
 
     // FIXME: rustdoc passes &[] instead of &krate.attrs here
-    let outputs = util::build_output_filenames(
-        &compiler.input,
-        &compiler.output_dir,
-        &compiler.output_file,
-        &compiler.temps_dir,
-        &krate.attrs,
-        sess,
-    );
+    let outputs = util::build_output_filenames(&krate.attrs, sess);
 
     let output_paths =
-        generated_output_paths(sess, &outputs, compiler.output_file.is_some(), crate_name);
+        generated_output_paths(sess, &outputs, sess.io.output_file.is_some(), crate_name);
 
     // Ensure the source file isn't accidentally overwritten during compilation.
-    if let Some(ref input_path) = compiler.input_path {
+    if let Some(ref input_path) = sess.io.input.opt_path() {
         if sess.opts.will_create_output_file() {
             if output_contains_path(&output_paths, input_path) {
                 let reported = sess.emit_err(InputFileWouldBeOverWritten { path: input_path });
@@ -701,7 +690,7 @@ pub fn prepare_outputs(
         }
     }
 
-    if let Some(ref dir) = compiler.temps_dir {
+    if let Some(ref dir) = sess.io.temps_dir {
         if fs::create_dir_all(dir).is_err() {
             let reported = sess.emit_err(TempsDirError);
             return Err(reported);
@@ -714,7 +703,7 @@ pub fn prepare_outputs(
         && sess.opts.output_types.len() == 1;
 
     if !only_dep_info {
-        if let Some(ref dir) = compiler.output_dir {
+        if let Some(ref dir) = sess.io.output_dir {
             if fs::create_dir_all(dir).is_err() {
                 let reported = sess.emit_err(OutDirError);
                 return Err(reported);
@@ -775,11 +764,8 @@ impl<'tcx> QueryContext<'tcx> {
 pub fn create_global_ctxt<'tcx>(
     compiler: &'tcx Compiler,
     lint_store: Lrc<LintStore>,
-    krate: Lrc<ast::Crate>,
     dep_graph: DepGraph,
-    resolver: Rc<RefCell<BoxedResolver>>,
-    outputs: OutputFilenames,
-    crate_name: Symbol,
+    untracked: Untracked,
     queries: &'tcx OnceCell<TcxQueries<'tcx>>,
     global_ctxt: &'tcx OnceCell<GlobalCtxt<'tcx>>,
     arena: &'tcx WorkerLocal<Arena<'tcx>>,
@@ -790,8 +776,6 @@ pub fn create_global_ctxt<'tcx>(
     // incr. comp. yet.
     dep_graph.assert_ignored();
 
-    let resolver_outputs = BoxedResolver::to_resolver_outputs(resolver);
-
     let sess = &compiler.session();
     let query_result_on_disk_cache = rustc_incremental::load_query_result_cache(sess);
 
@@ -810,12 +794,6 @@ pub fn create_global_ctxt<'tcx>(
         TcxQueries::new(local_providers, extern_providers, query_result_on_disk_cache)
     });
 
-    let ty::ResolverOutputs {
-        global_ctxt: untracked_resolutions,
-        ast_lowering: untracked_resolver_for_lowering,
-        untracked,
-    } = resolver_outputs;
-
     let gcx = sess.time("setup_global_ctxt", || {
         global_ctxt.get_or_init(move || {
             TyCtxt::create_global_ctxt(
@@ -832,19 +810,7 @@ pub fn create_global_ctxt<'tcx>(
         })
     });
 
-    let mut qcx = QueryContext { gcx };
-    qcx.enter(|tcx| {
-        let feed = tcx.feed_unit_query();
-        feed.resolver_for_lowering(
-            tcx.arena.alloc(Steal::new((untracked_resolver_for_lowering, krate))),
-        );
-        feed.resolutions(tcx.arena.alloc(untracked_resolutions));
-        feed.output_filenames(tcx.arena.alloc(std::sync::Arc::new(outputs)));
-        feed.features_query(sess.features_untracked());
-        let feed = tcx.feed_local_crate();
-        feed.crate_name(crate_name);
-    });
-    qcx
+    QueryContext { gcx }
 }
 
 /// Runs the resolution, type-checking, region checking and other
diff --git a/compiler/rustc_interface/src/queries.rs b/compiler/rustc_interface/src/queries.rs
index 041bb9eb7a1..d5a49dd75be 100644
--- a/compiler/rustc_interface/src/queries.rs
+++ b/compiler/rustc_interface/src/queries.rs
@@ -13,7 +13,7 @@ use rustc_incremental::DepGraphFuture;
 use rustc_lint::LintStore;
 use rustc_middle::arena::Arena;
 use rustc_middle::dep_graph::DepGraph;
-use rustc_middle::ty::{GlobalCtxt, TyCtxt};
+use rustc_middle::ty::{self, GlobalCtxt, TyCtxt};
 use rustc_query_impl::Queries as TcxQueries;
 use rustc_session::config::{self, OutputFilenames, OutputType};
 use rustc_session::{output::find_crate_name, Session};
@@ -90,7 +90,6 @@ pub struct Queries<'tcx> {
     register_plugins: Query<(ast::Crate, Lrc<LintStore>)>,
     expansion: Query<(Lrc<ast::Crate>, Rc<RefCell<BoxedResolver>>, Lrc<LintStore>)>,
     dep_graph: Query<DepGraph>,
-    prepare_outputs: Query<OutputFilenames>,
     global_ctxt: Query<QueryContext<'tcx>>,
     ongoing_codegen: Query<Box<dyn Any>>,
 }
@@ -109,7 +108,6 @@ impl<'tcx> Queries<'tcx> {
             register_plugins: Default::default(),
             expansion: Default::default(),
             dep_graph: Default::default(),
-            prepare_outputs: Default::default(),
             global_ctxt: Default::default(),
             ongoing_codegen: Default::default(),
         }
@@ -130,10 +128,8 @@ impl<'tcx> Queries<'tcx> {
     }
 
     pub fn parse(&self) -> Result<QueryResult<'_, ast::Crate>> {
-        self.parse.compute(|| {
-            passes::parse(self.session(), &self.compiler.input)
-                .map_err(|mut parse_error| parse_error.emit())
-        })
+        self.parse
+            .compute(|| passes::parse(self.session()).map_err(|mut parse_error| parse_error.emit()))
     }
 
     pub fn register_plugins(&self) -> Result<QueryResult<'_, (ast::Crate, Lrc<LintStore>)>> {
@@ -161,13 +157,13 @@ impl<'tcx> Queries<'tcx> {
         })
     }
 
-    pub fn crate_name(&self) -> Result<QueryResult<'_, Symbol>> {
+    fn crate_name(&self) -> Result<QueryResult<'_, Symbol>> {
         self.crate_name.compute(|| {
             Ok({
                 let parse_result = self.parse()?;
                 let krate = parse_result.borrow();
                 // parse `#[crate_name]` even if `--crate-name` was passed, to make sure it matches.
-                find_crate_name(self.session(), &krate.attrs, &self.compiler.input)
+                find_crate_name(self.session(), &krate.attrs)
             })
         })
     }
@@ -211,40 +207,42 @@ impl<'tcx> Queries<'tcx> {
         })
     }
 
-    pub fn prepare_outputs(&self) -> Result<QueryResult<'_, OutputFilenames>> {
-        self.prepare_outputs.compute(|| {
-            let expansion = self.expansion()?;
-            let (krate, boxed_resolver, _) = &*expansion.borrow();
-            let crate_name = *self.crate_name()?.borrow();
-            passes::prepare_outputs(
-                self.session(),
-                self.compiler,
-                krate,
-                &*boxed_resolver,
-                crate_name,
-            )
-        })
-    }
-
     pub fn global_ctxt(&'tcx self) -> Result<QueryResult<'_, QueryContext<'tcx>>> {
         self.global_ctxt.compute(|| {
             let crate_name = *self.crate_name()?.borrow();
-            let outputs = self.prepare_outputs()?.steal();
-            let dep_graph = self.dep_graph()?.borrow().clone();
             let (krate, resolver, lint_store) = self.expansion()?.steal();
-            Ok(passes::create_global_ctxt(
+
+            let outputs = passes::prepare_outputs(self.session(), &krate, &resolver, crate_name)?;
+
+            let ty::ResolverOutputs {
+                untracked,
+                global_ctxt: untracked_resolutions,
+                ast_lowering: untracked_resolver_for_lowering,
+            } = BoxedResolver::to_resolver_outputs(resolver);
+
+            let mut qcx = passes::create_global_ctxt(
                 self.compiler,
                 lint_store,
-                krate,
-                dep_graph,
-                resolver,
-                outputs,
-                crate_name,
+                self.dep_graph()?.steal(),
+                untracked,
                 &self.queries,
                 &self.gcx,
                 &self.arena,
                 &self.hir_arena,
-            ))
+            );
+
+            qcx.enter(|tcx| {
+                let feed = tcx.feed_unit_query();
+                feed.resolver_for_lowering(
+                    tcx.arena.alloc(Steal::new((untracked_resolver_for_lowering, krate))),
+                );
+                feed.resolutions(tcx.arena.alloc(untracked_resolutions));
+                feed.output_filenames(tcx.arena.alloc(std::sync::Arc::new(outputs)));
+                feed.features_query(tcx.sess.features_untracked());
+                let feed = tcx.feed_local_crate();
+                feed.crate_name(crate_name);
+            });
+            Ok(qcx)
         })
     }
 
diff --git a/compiler/rustc_interface/src/tests.rs b/compiler/rustc_interface/src/tests.rs
index 07b28cc86ce..f94bc4d4c66 100644
--- a/compiler/rustc_interface/src/tests.rs
+++ b/compiler/rustc_interface/src/tests.rs
@@ -4,6 +4,7 @@ use crate::interface::parse_cfgspecs;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_errors::{emitter::HumanReadableErrorType, registry, ColorConfig};
 use rustc_session::config::rustc_optgroups;
+use rustc_session::config::Input;
 use rustc_session::config::TraitSolver;
 use rustc_session::config::{build_configuration, build_session_options, to_crate_config};
 use rustc_session::config::{
@@ -17,9 +18,11 @@ use rustc_session::config::{InstrumentCoverage, Passes};
 use rustc_session::lint::Level;
 use rustc_session::search_paths::SearchPath;
 use rustc_session::utils::{CanonicalizedPath, NativeLib, NativeLibKind};
+use rustc_session::CompilerIO;
 use rustc_session::{build_session, getopts, Session};
 use rustc_span::edition::{Edition, DEFAULT_EDITION};
 use rustc_span::symbol::sym;
+use rustc_span::FileName;
 use rustc_span::SourceFileHashAlgorithm;
 use rustc_target::spec::{CodeModel, LinkerFlavorCli, MergeFunctions, PanicStrategy, RelocModel};
 use rustc_target::spec::{RelroLevel, SanitizerSet, SplitDebuginfo, StackProtector, TlsModel};
@@ -39,7 +42,14 @@ fn build_session_options_and_crate_config(matches: getopts::Matches) -> (Options
 fn mk_session(matches: getopts::Matches) -> (Session, CfgSpecs) {
     let registry = registry::Registry::new(&[]);
     let (sessopts, cfg) = build_session_options_and_crate_config(matches);
-    let sess = build_session(sessopts, None, None, registry, Default::default(), None, None);
+    let temps_dir = sessopts.unstable_opts.temps_dir.as_deref().map(PathBuf::from);
+    let io = CompilerIO {
+        input: Input::Str { name: FileName::Custom(String::new()), input: String::new() },
+        output_dir: None,
+        output_file: None,
+        temps_dir,
+    };
+    let sess = build_session(sessopts, io, None, registry, Default::default(), None, None);
     (sess, cfg)
 }
 
diff --git a/compiler/rustc_interface/src/util.rs b/compiler/rustc_interface/src/util.rs
index 02a7756c8d4..54363e07b97 100644
--- a/compiler/rustc_interface/src/util.rs
+++ b/compiler/rustc_interface/src/util.rs
@@ -8,7 +8,7 @@ use rustc_parse::validate_attr;
 use rustc_session as session;
 use rustc_session::config::CheckCfg;
 use rustc_session::config::{self, CrateType};
-use rustc_session::config::{ErrorOutputType, Input, OutputFilenames};
+use rustc_session::config::{ErrorOutputType, OutputFilenames};
 use rustc_session::filesearch::sysroot_candidates;
 use rustc_session::lint::{self, BuiltinLintDiagnostics, LintBuffer};
 use rustc_session::parse::CrateConfig;
@@ -17,6 +17,7 @@ use rustc_span::edition::Edition;
 use rustc_span::lev_distance::find_best_match_for_name;
 use rustc_span::source_map::FileLoader;
 use rustc_span::symbol::{sym, Symbol};
+use session::CompilerIO;
 use std::env;
 use std::env::consts::{DLL_PREFIX, DLL_SUFFIX};
 use std::mem;
@@ -58,7 +59,7 @@ pub fn create_session(
     cfg: FxHashSet<(String, Option<String>)>,
     check_cfg: CheckCfg,
     file_loader: Option<Box<dyn FileLoader + Send + Sync + 'static>>,
-    input_path: Option<PathBuf>,
+    io: CompilerIO,
     lint_caps: FxHashMap<lint::LintId, lint::Level>,
     make_codegen_backend: Option<
         Box<dyn FnOnce(&config::Options) -> Box<dyn CodegenBackend> + Send>,
@@ -89,7 +90,7 @@ pub fn create_session(
 
     let mut sess = session::build_session(
         sopts,
-        input_path,
+        io,
         bundle,
         descriptions,
         lint_caps,
@@ -486,20 +487,13 @@ pub fn collect_crate_types(session: &Session, attrs: &[ast::Attribute]) -> Vec<C
     base
 }
 
-pub fn build_output_filenames(
-    input: &Input,
-    odir: &Option<PathBuf>,
-    ofile: &Option<PathBuf>,
-    temps_dir: &Option<PathBuf>,
-    attrs: &[ast::Attribute],
-    sess: &Session,
-) -> OutputFilenames {
-    match *ofile {
+pub fn build_output_filenames(attrs: &[ast::Attribute], sess: &Session) -> OutputFilenames {
+    match sess.io.output_file {
         None => {
             // "-" as input file will cause the parser to read from stdin so we
             // have to make up a name
             // We want to toss everything after the final '.'
-            let dirpath = (*odir).as_ref().cloned().unwrap_or_default();
+            let dirpath = sess.io.output_dir.clone().unwrap_or_default();
 
             // If a crate name is present, we use it as the link name
             let stem = sess
@@ -507,13 +501,13 @@ pub fn build_output_filenames(
                 .crate_name
                 .clone()
                 .or_else(|| rustc_attr::find_crate_name(sess, attrs).map(|n| n.to_string()))
-                .unwrap_or_else(|| input.filestem().to_owned());
+                .unwrap_or_else(|| sess.io.input.filestem().to_owned());
 
             OutputFilenames::new(
                 dirpath,
                 stem,
                 None,
-                temps_dir.clone(),
+                sess.io.temps_dir.clone(),
                 sess.opts.cg.extra_filename.clone(),
                 sess.opts.output_types.clone(),
             )
@@ -534,7 +528,7 @@ pub fn build_output_filenames(
                 }
                 Some(out_file.clone())
             };
-            if *odir != None {
+            if sess.io.output_dir != None {
                 sess.warn("ignoring --out-dir flag due to -o flag");
             }
 
@@ -542,7 +536,7 @@ pub fn build_output_filenames(
                 out_file.parent().unwrap_or_else(|| Path::new("")).to_path_buf(),
                 out_file.file_stem().unwrap_or_default().to_str().unwrap().to_string(),
                 ofile,
-                temps_dir.clone(),
+                sess.io.temps_dir.clone(),
                 sess.opts.cg.extra_filename.clone(),
                 sess.opts.output_types.clone(),
             )
diff --git a/compiler/rustc_lint/src/builtin.rs b/compiler/rustc_lint/src/builtin.rs
index 6f445426df7..fe188162cf8 100644
--- a/compiler/rustc_lint/src/builtin.rs
+++ b/compiler/rustc_lint/src/builtin.rs
@@ -72,7 +72,7 @@ use rustc_span::symbol::{kw, sym, Ident, Symbol};
 use rustc_span::{BytePos, InnerSpan, Span};
 use rustc_target::abi::{Abi, VariantIdx};
 use rustc_trait_selection::infer::{InferCtxtExt, TyCtxtInferExt};
-use rustc_trait_selection::traits::{self, misc::can_type_implement_copy, EvaluationResult};
+use rustc_trait_selection::traits::{self, misc::type_allowed_to_implement_copy};
 
 use crate::nonstandard_style::{method_context, MethodLateContext};
 
@@ -709,12 +709,14 @@ impl<'tcx> LateLintPass<'tcx> for MissingCopyImplementations {
 
         // We shouldn't recommend implementing `Copy` on stateful things,
         // such as iterators.
-        if let Some(iter_trait) = cx.tcx.get_diagnostic_item(sym::Iterator) {
-            if cx.tcx.infer_ctxt().build().type_implements_trait(iter_trait, [ty], param_env)
-                == EvaluationResult::EvaluatedToOk
-            {
-                return;
-            }
+        if let Some(iter_trait) = cx.tcx.get_diagnostic_item(sym::Iterator)
+            && cx.tcx
+                .infer_ctxt()
+                .build()
+                .type_implements_trait(iter_trait, [ty], param_env)
+                .must_apply_modulo_regions()
+        {
+            return;
         }
 
         // Default value of clippy::trivially_copy_pass_by_ref
@@ -726,7 +728,7 @@ impl<'tcx> LateLintPass<'tcx> for MissingCopyImplementations {
             }
         }
 
-        if can_type_implement_copy(
+        if type_allowed_to_implement_copy(
             cx.tcx,
             param_env,
             ty,
diff --git a/compiler/rustc_lint/src/context.rs b/compiler/rustc_lint/src/context.rs
index c9b9a622571..8046cc21cea 100644
--- a/compiler/rustc_lint/src/context.rs
+++ b/compiler/rustc_lint/src/context.rs
@@ -825,21 +825,24 @@ pub trait LintContext: Sized {
                     debug!(?param_span, ?use_span, ?deletion_span);
                     db.span_label(param_span, "this lifetime...");
                     db.span_label(use_span, "...is used only here");
-                    let msg = "elide the single-use lifetime";
-                    let (use_span, replace_lt) = if elide {
-                        let use_span = sess.source_map().span_extend_while(
-                            use_span,
-                            char::is_whitespace,
-                        ).unwrap_or(use_span);
-                        (use_span, String::new())
-                    } else {
-                        (use_span, "'_".to_owned())
-                    };
-                    db.multipart_suggestion(
-                        msg,
-                        vec![(deletion_span, String::new()), (use_span, replace_lt)],
-                        Applicability::MachineApplicable,
-                    );
+                    if let Some(deletion_span) = deletion_span {
+                        let msg = "elide the single-use lifetime";
+                        let (use_span, replace_lt) = if elide {
+                            let use_span = sess.source_map().span_extend_while(
+                                use_span,
+                                char::is_whitespace,
+                            ).unwrap_or(use_span);
+                            (use_span, String::new())
+                        } else {
+                            (use_span, "'_".to_owned())
+                        };
+                        debug!(?deletion_span, ?use_span);
+                        db.multipart_suggestion(
+                            msg,
+                            vec![(deletion_span, String::new()), (use_span, replace_lt)],
+                            Applicability::MachineApplicable,
+                        );
+                    }
                 },
                 BuiltinLintDiagnostics::SingleUseLifetime {
                     param_span: _,
@@ -847,12 +850,14 @@ pub trait LintContext: Sized {
                     deletion_span,
                 } => {
                     debug!(?deletion_span);
-                    db.span_suggestion(
-                        deletion_span,
-                        "elide the unused lifetime",
-                        "",
-                        Applicability::MachineApplicable,
-                    );
+                    if let Some(deletion_span) = deletion_span {
+                        db.span_suggestion(
+                            deletion_span,
+                            "elide the unused lifetime",
+                            "",
+                            Applicability::MachineApplicable,
+                        );
+                    }
                 },
                 BuiltinLintDiagnostics::NamedArgumentUsedPositionally{ position_sp_to_replace, position_sp_for_msg, named_arg_sp, named_arg_name, is_formatting_arg} => {
                     db.span_label(named_arg_sp, "this named argument is referred to by position in formatting string");
diff --git a/compiler/rustc_lint/src/early.rs b/compiler/rustc_lint/src/early.rs
index f9b2df49592..337a19dd024 100644
--- a/compiler/rustc_lint/src/early.rs
+++ b/compiler/rustc_lint/src/early.rs
@@ -248,7 +248,9 @@ impl<'a, T: EarlyLintPass> ast_visit::Visitor<'a> for EarlyContextAndPass<'a, T>
     }
 
     fn visit_where_predicate(&mut self, p: &'a ast::WherePredicate) {
+        lint_callback!(self, enter_where_predicate, p);
         ast_visit::walk_where_predicate(self, p);
+        lint_callback!(self, exit_where_predicate, p);
     }
 
     fn visit_poly_trait_ref(&mut self, t: &'a ast::PolyTraitRef) {
diff --git a/compiler/rustc_lint/src/internal.rs b/compiler/rustc_lint/src/internal.rs
index 5eb54cc0034..6cefaea2bc7 100644
--- a/compiler/rustc_lint/src/internal.rs
+++ b/compiler/rustc_lint/src/internal.rs
@@ -187,9 +187,9 @@ impl<'tcx> LateLintPass<'tcx> for TyTyKind {
                         },
                         None => cx.emit_spanned_lint(USAGE_OF_TY_TYKIND, path.span, TykindDiag),
                     }
-                } else if !ty.span.from_expansion() && path.segments.len() > 1 && let Some(t) = is_ty_or_ty_ctxt(cx, &path) {
+                } else if !ty.span.from_expansion() && path.segments.len() > 1 && let Some(ty) = is_ty_or_ty_ctxt(cx, &path) {
                     cx.emit_spanned_lint(USAGE_OF_QUALIFIED_TY, path.span, TyQualified {
-                        ty: t.clone(),
+                        ty,
                         suggestion: path.span,
                     });
                 }
diff --git a/compiler/rustc_lint/src/lib.rs b/compiler/rustc_lint/src/lib.rs
index 3d818154cb9..d6be4da0328 100644
--- a/compiler/rustc_lint/src/lib.rs
+++ b/compiler/rustc_lint/src/lib.rs
@@ -145,7 +145,7 @@ early_lint_methods!(
     [
         pub BuiltinCombinedEarlyLintPass,
         [
-            UnusedParens: UnusedParens,
+            UnusedParens: UnusedParens::new(),
             UnusedBraces: UnusedBraces,
             UnusedImportBraces: UnusedImportBraces,
             UnsafeCode: UnsafeCode,
diff --git a/compiler/rustc_lint/src/pass_by_value.rs b/compiler/rustc_lint/src/pass_by_value.rs
index 57482a9edba..392e13f2fa9 100644
--- a/compiler/rustc_lint/src/pass_by_value.rs
+++ b/compiler/rustc_lint/src/pass_by_value.rs
@@ -32,7 +32,7 @@ impl<'tcx> LateLintPass<'tcx> for PassByValue {
                     cx.emit_spanned_lint(
                         PASS_BY_VALUE,
                         ty.span,
-                        PassByValueDiag { ty: t.clone(), suggestion: ty.span },
+                        PassByValueDiag { ty: t, suggestion: ty.span },
                     );
                 }
             }
diff --git a/compiler/rustc_lint/src/passes.rs b/compiler/rustc_lint/src/passes.rs
index 5558156a4b9..0bf01c4e567 100644
--- a/compiler/rustc_lint/src/passes.rs
+++ b/compiler/rustc_lint/src/passes.rs
@@ -171,6 +171,9 @@ macro_rules! early_lint_methods {
 
             /// Counterpart to `enter_lint_attrs`.
             fn exit_lint_attrs(a: &[ast::Attribute]);
+
+            fn enter_where_predicate(a: &ast::WherePredicate);
+            fn exit_where_predicate(a: &ast::WherePredicate);
         ]);
     )
 }
diff --git a/compiler/rustc_lint/src/types.rs b/compiler/rustc_lint/src/types.rs
index f2ab44ac97c..be47a3e238c 100644
--- a/compiler/rustc_lint/src/types.rs
+++ b/compiler/rustc_lint/src/types.rs
@@ -1147,7 +1147,7 @@ impl<'a, 'tcx> ImproperCTypesVisitor<'a, 'tcx> {
 
             fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
                 if !ty.has_opaque_types() {
-                    return ControlFlow::CONTINUE;
+                    return ControlFlow::Continue(());
                 }
 
                 if let ty::Alias(ty::Opaque, ..) = ty.kind() {
diff --git a/compiler/rustc_lint/src/unused.rs b/compiler/rustc_lint/src/unused.rs
index f2ee9ab1a19..4c9b3df2dbd 100644
--- a/compiler/rustc_lint/src/unused.rs
+++ b/compiler/rustc_lint/src/unused.rs
@@ -824,7 +824,17 @@ declare_lint! {
     "`if`, `match`, `while` and `return` do not need parentheses"
 }
 
-declare_lint_pass!(UnusedParens => [UNUSED_PARENS]);
+pub struct UnusedParens {
+    with_self_ty_parens: bool,
+}
+
+impl UnusedParens {
+    pub fn new() -> Self {
+        Self { with_self_ty_parens: false }
+    }
+}
+
+impl_lint_pass!(UnusedParens => [UNUSED_PARENS]);
 
 impl UnusedDelimLint for UnusedParens {
     const DELIM_STR: &'static str = "parentheses";
@@ -999,36 +1009,58 @@ impl EarlyLintPass for UnusedParens {
     }
 
     fn check_ty(&mut self, cx: &EarlyContext<'_>, ty: &ast::Ty) {
-        if let ast::TyKind::Paren(r) = &ty.kind {
-            match &r.kind {
-                ast::TyKind::TraitObject(..) => {}
-                ast::TyKind::BareFn(b) if b.generic_params.len() > 0 => {}
-                ast::TyKind::ImplTrait(_, bounds) if bounds.len() > 1 => {}
-                ast::TyKind::Array(_, len) => {
-                    self.check_unused_delims_expr(
-                        cx,
-                        &len.value,
-                        UnusedDelimsCtx::ArrayLenExpr,
-                        false,
-                        None,
-                        None,
-                    );
-                }
-                _ => {
-                    let spans = if let Some(r) = r.span.find_ancestor_inside(ty.span) {
-                        Some((ty.span.with_hi(r.lo()), ty.span.with_lo(r.hi())))
-                    } else {
-                        None
-                    };
-                    self.emit_unused_delims(cx, ty.span, spans, "type", (false, false));
+        match &ty.kind {
+            ast::TyKind::Array(_, len) => {
+                self.check_unused_delims_expr(
+                    cx,
+                    &len.value,
+                    UnusedDelimsCtx::ArrayLenExpr,
+                    false,
+                    None,
+                    None,
+                );
+            }
+            ast::TyKind::Paren(r) => {
+                match &r.kind {
+                    ast::TyKind::TraitObject(..) => {}
+                    ast::TyKind::BareFn(b)
+                        if self.with_self_ty_parens && b.generic_params.len() > 0 => {}
+                    ast::TyKind::ImplTrait(_, bounds) if bounds.len() > 1 => {}
+                    _ => {
+                        let spans = if let Some(r) = r.span.find_ancestor_inside(ty.span) {
+                            Some((ty.span.with_hi(r.lo()), ty.span.with_lo(r.hi())))
+                        } else {
+                            None
+                        };
+                        self.emit_unused_delims(cx, ty.span, spans, "type", (false, false));
+                    }
                 }
+                self.with_self_ty_parens = false;
             }
+            _ => {}
         }
     }
 
     fn check_item(&mut self, cx: &EarlyContext<'_>, item: &ast::Item) {
         <Self as UnusedDelimLint>::check_item(self, cx, item)
     }
+
+    fn enter_where_predicate(&mut self, _: &EarlyContext<'_>, pred: &ast::WherePredicate) {
+        use rustc_ast::{WhereBoundPredicate, WherePredicate};
+        if let WherePredicate::BoundPredicate(WhereBoundPredicate {
+                bounded_ty,
+                bound_generic_params,
+                ..
+            }) = pred &&
+            let ast::TyKind::Paren(_) = &bounded_ty.kind &&
+            bound_generic_params.is_empty() {
+                self.with_self_ty_parens = true;
+        }
+    }
+
+    fn exit_where_predicate(&mut self, _: &EarlyContext<'_>, _: &ast::WherePredicate) {
+        assert!(!self.with_self_ty_parens);
+    }
 }
 
 declare_lint! {
@@ -1095,17 +1127,21 @@ impl UnusedDelimLint for UnusedBraces {
                 //      ```
                 // - the block has no attribute and was not created inside a macro
                 // - if the block is an `anon_const`, the inner expr must be a literal
-                //      (do not lint `struct A<const N: usize>; let _: A<{ 2 + 3 }>;`)
-                //
+                //   not created by a macro, i.e. do not lint on:
+                //      ```
+                //      struct A<const N: usize>;
+                //      let _: A<{ 2 + 3 }>;
+                //      let _: A<{produces_literal!()}>;
+                //      ```
                 // FIXME(const_generics): handle paths when #67075 is fixed.
                 if let [stmt] = inner.stmts.as_slice() {
                     if let ast::StmtKind::Expr(ref expr) = stmt.kind {
                         if !Self::is_expr_delims_necessary(expr, followed_by_block, false)
                             && (ctx != UnusedDelimsCtx::AnonConst
-                                || matches!(expr.kind, ast::ExprKind::Lit(_)))
+                                || (matches!(expr.kind, ast::ExprKind::Lit(_))
+                                    && !expr.span.from_expansion()))
                             && !cx.sess().source_map().is_multiline(value.span)
                             && value.attrs.is_empty()
-                            && !expr.span.from_expansion()
                             && !value.span.from_expansion()
                             && !inner.span.from_expansion()
                         {
diff --git a/compiler/rustc_lint_defs/src/builtin.rs b/compiler/rustc_lint_defs/src/builtin.rs
index 6cdf5097083..b6481d70bc8 100644
--- a/compiler/rustc_lint_defs/src/builtin.rs
+++ b/compiler/rustc_lint_defs/src/builtin.rs
@@ -708,7 +708,7 @@ declare_lint! {
     ///
     /// ### Example
     ///
-    /// ```rust
+    /// ```rust,compile_fail
     /// pub enum Enum {
     ///     Foo,
     ///     Bar,
@@ -743,7 +743,7 @@ declare_lint! {
     /// [identifier pattern]: https://doc.rust-lang.org/reference/patterns.html#identifier-patterns
     /// [path pattern]: https://doc.rust-lang.org/reference/patterns.html#path-patterns
     pub BINDINGS_WITH_VARIANT_NAME,
-    Warn,
+    Deny,
     "detects pattern bindings with the same name as one of the matched variants"
 }
 
@@ -2024,6 +2024,73 @@ declare_lint! {
 }
 
 declare_lint! {
+    /// The `proc_macro_derive_resolution_fallback` lint detects proc macro
+    /// derives using inaccessible names from parent modules.
+    ///
+    /// ### Example
+    ///
+    /// ```rust,ignore (proc-macro)
+    /// // foo.rs
+    /// #![crate_type = "proc-macro"]
+    ///
+    /// extern crate proc_macro;
+    ///
+    /// use proc_macro::*;
+    ///
+    /// #[proc_macro_derive(Foo)]
+    /// pub fn foo1(a: TokenStream) -> TokenStream {
+    ///     drop(a);
+    ///     "mod __bar { static mut BAR: Option<Something> = None; }".parse().unwrap()
+    /// }
+    /// ```
+    ///
+    /// ```rust,ignore (needs-dependency)
+    /// // bar.rs
+    /// #[macro_use]
+    /// extern crate foo;
+    ///
+    /// struct Something;
+    ///
+    /// #[derive(Foo)]
+    /// struct Another;
+    ///
+    /// fn main() {}
+    /// ```
+    ///
+    /// This will produce:
+    ///
+    /// ```text
+    /// warning: cannot find type `Something` in this scope
+    ///  --> src/main.rs:8:10
+    ///   |
+    /// 8 | #[derive(Foo)]
+    ///   |          ^^^ names from parent modules are not accessible without an explicit import
+    ///   |
+    ///   = note: `#[warn(proc_macro_derive_resolution_fallback)]` on by default
+    ///   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+    ///   = note: for more information, see issue #50504 <https://github.com/rust-lang/rust/issues/50504>
+    /// ```
+    ///
+    /// ### Explanation
+    ///
+    /// If a proc-macro generates a module, the compiler unintentionally
+    /// allowed items in that module to refer to items in the crate root
+    /// without importing them. This is a [future-incompatible] lint to
+    /// transition this to a hard error in the future. See [issue #50504] for
+    /// more details.
+    ///
+    /// [issue #50504]: https://github.com/rust-lang/rust/issues/50504
+    /// [future-incompatible]: ../index.md#future-incompatible-lints
+    pub PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
+    Deny,
+    "detects proc macro derives using inaccessible names from parent modules",
+    @future_incompatible = FutureIncompatibleInfo {
+        reference: "issue #83583 <https://github.com/rust-lang/rust/issues/83583>",
+        reason: FutureIncompatibilityReason::FutureReleaseErrorReportNow,
+    };
+}
+
+declare_lint! {
     /// The `macro_use_extern_crate` lint detects the use of the
     /// [`macro_use` attribute].
     ///
@@ -2948,6 +3015,7 @@ declare_lint! {
     "trailing semicolon in macro body used as expression",
     @future_incompatible = FutureIncompatibleInfo {
         reference: "issue #79813 <https://github.com/rust-lang/rust/issues/79813>",
+        reason: FutureIncompatibilityReason::FutureReleaseErrorReportNow,
     };
 }
 
@@ -3261,6 +3329,7 @@ declare_lint_pass! {
         UNSTABLE_NAME_COLLISIONS,
         IRREFUTABLE_LET_PATTERNS,
         WHERE_CLAUSES_OBJECT_SAFETY,
+        PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
         MACRO_USE_EXTERN_CRATE,
         MACRO_EXPANDED_MACRO_EXPORTS_ACCESSED_BY_ABSOLUTE_PATHS,
         ILL_FORMED_ATTRIBUTE_INPUT,
diff --git a/compiler/rustc_lint_defs/src/lib.rs b/compiler/rustc_lint_defs/src/lib.rs
index f4b4c5168bf..7054d1e9f10 100644
--- a/compiler/rustc_lint_defs/src/lib.rs
+++ b/compiler/rustc_lint_defs/src/lib.rs
@@ -6,8 +6,9 @@
 extern crate rustc_macros;
 
 pub use self::Level::*;
-use rustc_ast::node_id::{NodeId, NodeMap};
+use rustc_ast::node_id::NodeId;
 use rustc_ast::{AttrId, Attribute};
+use rustc_data_structures::fx::FxIndexMap;
 use rustc_data_structures::stable_hasher::{HashStable, StableHasher, ToStableHashKey};
 use rustc_error_messages::{DiagnosticMessage, MultiSpan};
 use rustc_hir::HashStableContext;
@@ -502,7 +503,7 @@ pub enum BuiltinLintDiagnostics {
         param_span: Span,
         /// Span of the code that should be removed when eliding this lifetime.
         /// This span should include leading or trailing comma.
-        deletion_span: Span,
+        deletion_span: Option<Span>,
         /// Span of the single use, or None if the lifetime is never used.
         /// If true, the lifetime will be fully elided.
         use_span: Option<(Span, bool)>,
@@ -544,7 +545,7 @@ pub struct BufferedEarlyLint {
 
 #[derive(Default)]
 pub struct LintBuffer {
-    pub map: NodeMap<Vec<BufferedEarlyLint>>,
+    pub map: FxIndexMap<NodeId, Vec<BufferedEarlyLint>>,
 }
 
 impl LintBuffer {
diff --git a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
index 8f94e8a4ab2..87b0e1273eb 100644
--- a/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
+++ b/compiler/rustc_llvm/llvm-wrapper/RustWrapper.cpp
@@ -1349,18 +1349,16 @@ extern "C" LLVMTypeKind LLVMRustGetTypeKind(LLVMTypeRef Ty) {
     return LLVMBFloatTypeKind;
   case Type::X86_AMXTyID:
     return LLVMX86_AMXTypeKind;
-#if LLVM_VERSION_GE(15, 0) && LLVM_VERSION_LT(16, 0)
-  case Type::DXILPointerTyID:
-    report_fatal_error("Rust does not support DirectX typed pointers.");
-    break;
-#endif
-#if LLVM_VERSION_GE(16, 0)
-  case Type::TypedPointerTyID:
-    report_fatal_error("Rust does not support typed pointers.");
-    break;
-#endif
+  default:
+    {
+      std::string error;
+      llvm::raw_string_ostream stream(error);
+      stream << "Rust does not support the TypeID: " << unwrap(Ty)->getTypeID()
+             << " for the type: " << *unwrap(Ty);
+      stream.flush();
+      report_fatal_error(error.c_str());
+    }
   }
-  report_fatal_error("Unhandled TypeID.");
 }
 
 DEFINE_SIMPLE_CONVERSION_FUNCTIONS(SMDiagnostic, LLVMSMDiagnosticRef)
diff --git a/compiler/rustc_macros/src/type_visitable.rs b/compiler/rustc_macros/src/type_visitable.rs
index 14e6aa6e0c1..1f95661ce9d 100644
--- a/compiler/rustc_macros/src/type_visitable.rs
+++ b/compiler/rustc_macros/src/type_visitable.rs
@@ -26,7 +26,7 @@ pub fn type_visitable_derive(mut s: synstructure::Structure<'_>) -> proc_macro2:
                 __visitor: &mut __V
             ) -> ::std::ops::ControlFlow<__V::BreakTy> {
                 match *self { #body_visit }
-                ::std::ops::ControlFlow::CONTINUE
+                ::std::ops::ControlFlow::Continue(())
             }
         },
     )
diff --git a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
index cb451931dfe..6fd5bd52abe 100644
--- a/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
+++ b/compiler/rustc_metadata/src/rmeta/decoder/cstore_impl.rs
@@ -223,6 +223,15 @@ provide! { tcx, def_id, other, cdata,
     generator_kind => { table }
     trait_def => { table }
     deduced_param_attrs => { table }
+    is_type_alias_impl_trait => {
+        debug_assert_eq!(tcx.def_kind(def_id), DefKind::OpaqueTy);
+        cdata
+            .root
+            .tables
+            .is_type_alias_impl_trait
+            .get(cdata, def_id.index)
+            .is_some()
+    }
     collect_return_position_impl_trait_in_trait_tys => {
         Ok(cdata
             .root
@@ -382,7 +391,7 @@ pub(in crate::rmeta) fn provide(providers: &mut Providers) {
             // keys from the former.
             // This is a rudimentary check that does not catch all cases,
             // just the easiest.
-            let mut fallback_map: DefIdMap<DefId> = Default::default();
+            let mut fallback_map: Vec<(DefId, DefId)> = Default::default();
 
             // Issue 46112: We want the map to prefer the shortest
             // paths when reporting the path to an item. Therefore we
@@ -412,12 +421,12 @@ pub(in crate::rmeta) fn provide(providers: &mut Providers) {
 
                 if let Some(def_id) = child.res.opt_def_id() {
                     if child.ident.name == kw::Underscore {
-                        fallback_map.insert(def_id, parent);
+                        fallback_map.push((def_id, parent));
                         return;
                     }
 
                     if ty::util::is_doc_hidden(tcx, parent) {
-                        fallback_map.insert(def_id, parent);
+                        fallback_map.push((def_id, parent));
                         return;
                     }
 
@@ -451,6 +460,7 @@ pub(in crate::rmeta) fn provide(providers: &mut Providers) {
             // Fill in any missing entries with the less preferable path.
             // If this path re-exports the child as `_`, we still use this
             // path in a diagnostic that suggests importing `::*`.
+
             for (child, parent) in fallback_map {
                 visible_parent_map.entry(child).or_insert(parent);
             }
diff --git a/compiler/rustc_metadata/src/rmeta/encoder.rs b/compiler/rustc_metadata/src/rmeta/encoder.rs
index 58b91e7b4f8..8f7a61b72f8 100644
--- a/compiler/rustc_metadata/src/rmeta/encoder.rs
+++ b/compiler/rustc_metadata/src/rmeta/encoder.rs
@@ -888,8 +888,8 @@ fn should_encode_mir(tcx: TyCtxt<'_>, def_id: LocalDefId) -> (bool, bool) {
         | DefKind::AssocConst
         | DefKind::Static(..)
         | DefKind::Const => (true, false),
-        // Full-fledged functions
-        DefKind::AssocFn | DefKind::Fn => {
+        // Full-fledged functions + closures
+        DefKind::AssocFn | DefKind::Fn | DefKind::Closure => {
             let generics = tcx.generics_of(def_id);
             let needs_inline = (generics.requires_monomorphization(tcx)
                 || tcx.codegen_fn_attrs(def_id).requests_inline())
@@ -900,15 +900,6 @@ fn should_encode_mir(tcx: TyCtxt<'_>, def_id: LocalDefId) -> (bool, bool) {
             let always_encode_mir = tcx.sess.opts.unstable_opts.always_encode_mir;
             (is_const_fn, needs_inline || always_encode_mir)
         }
-        // Closures can't be const fn.
-        DefKind::Closure => {
-            let generics = tcx.generics_of(def_id);
-            let needs_inline = (generics.requires_monomorphization(tcx)
-                || tcx.codegen_fn_attrs(def_id).requests_inline())
-                && tcx.sess.opts.output_types.should_codegen();
-            let always_encode_mir = tcx.sess.opts.unstable_opts.always_encode_mir;
-            (false, needs_inline || always_encode_mir)
-        }
         // Generators require optimized MIR to compute layout.
         DefKind::Generator => (false, true),
         // The others don't have MIR.
@@ -1196,8 +1187,11 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
                 record!(self.tables.trait_impl_trait_tys[def_id] <- table);
             }
         }
-        let inherent_impls = tcx.crate_inherent_impls(());
-        for (def_id, implementations) in inherent_impls.inherent_impls.iter() {
+        let inherent_impls = tcx.with_stable_hashing_context(|hcx| {
+            tcx.crate_inherent_impls(()).inherent_impls.to_sorted(&hcx, true)
+        });
+
+        for (def_id, implementations) in inherent_impls {
             if implementations.is_empty() {
                 continue;
             }
@@ -1521,8 +1515,11 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
             hir::ItemKind::Mod(ref m) => {
                 return self.encode_info_for_mod(item.owner_id.def_id, m);
             }
-            hir::ItemKind::OpaqueTy(..) => {
+            hir::ItemKind::OpaqueTy(ref opaque) => {
                 self.encode_explicit_item_bounds(def_id);
+                if matches!(opaque.origin, hir::OpaqueTyOrigin::TyAlias) {
+                    self.tables.is_type_alias_impl_trait.set(def_id.index, ());
+                }
             }
             hir::ItemKind::Enum(..) => {
                 let adt_def = self.tcx.adt_def(def_id);
diff --git a/compiler/rustc_metadata/src/rmeta/mod.rs b/compiler/rustc_metadata/src/rmeta/mod.rs
index 5b7b096b4ed..5066dbbb90f 100644
--- a/compiler/rustc_metadata/src/rmeta/mod.rs
+++ b/compiler/rustc_metadata/src/rmeta/mod.rs
@@ -404,6 +404,8 @@ define_tables! {
     proc_macro: Table<DefIndex, MacroKind>,
     module_reexports: Table<DefIndex, LazyArray<ModChild>>,
     deduced_param_attrs: Table<DefIndex, LazyArray<DeducedParamAttrs>>,
+    // Slot is full when opaque is TAIT.
+    is_type_alias_impl_trait: Table<DefIndex, ()>,
 
     trait_impl_trait_tys: Table<DefIndex, LazyValue<FxHashMap<DefId, Ty<'static>>>>,
 }
diff --git a/compiler/rustc_middle/src/infer/canonical.rs b/compiler/rustc_middle/src/infer/canonical.rs
index 614cf1a0051..43583b5723e 100644
--- a/compiler/rustc_middle/src/infer/canonical.rs
+++ b/compiler/rustc_middle/src/infer/canonical.rs
@@ -68,6 +68,22 @@ pub struct CanonicalVarValues<'tcx> {
     pub var_values: IndexVec<BoundVar, GenericArg<'tcx>>,
 }
 
+impl CanonicalVarValues<'_> {
+    pub fn is_identity(&self) -> bool {
+        self.var_values.iter_enumerated().all(|(bv, arg)| match arg.unpack() {
+            ty::GenericArgKind::Lifetime(r) => {
+                matches!(*r, ty::ReLateBound(ty::INNERMOST, br) if br.var == bv)
+            }
+            ty::GenericArgKind::Type(ty) => {
+                matches!(*ty.kind(), ty::Bound(ty::INNERMOST, bt) if bt.var == bv)
+            }
+            ty::GenericArgKind::Const(ct) => {
+                matches!(ct.kind(), ty::ConstKind::Bound(ty::INNERMOST, bc) if bc == bv)
+            }
+        })
+    }
+}
+
 /// When we canonicalize a value to form a query, we wind up replacing
 /// various parts of it with canonical variables. This struct stores
 /// those replaced bits to remember for when we process the query
@@ -323,6 +339,12 @@ TrivialTypeTraversalAndLiftImpls! {
 }
 
 impl<'tcx> CanonicalVarValues<'tcx> {
+    /// Creates dummy var values which should not be used in a
+    /// canonical response.
+    pub fn dummy() -> CanonicalVarValues<'tcx> {
+        CanonicalVarValues { var_values: Default::default() }
+    }
+
     #[inline]
     pub fn len(&self) -> usize {
         self.var_values.len()
diff --git a/compiler/rustc_middle/src/macros.rs b/compiler/rustc_middle/src/macros.rs
index 5ca4d260179..250f3d0797e 100644
--- a/compiler/rustc_middle/src/macros.rs
+++ b/compiler/rustc_middle/src/macros.rs
@@ -93,7 +93,7 @@ macro_rules! TrivialTypeTraversalImpls {
                     _: &mut F)
                     -> ::std::ops::ControlFlow<F::BreakTy>
                 {
-                    ::std::ops::ControlFlow::CONTINUE
+                    ::std::ops::ControlFlow::Continue(())
                 }
             }
         )+
@@ -219,7 +219,7 @@ macro_rules! EnumTypeTraversalImpl {
                         $($crate::ty::visit::TypeVisitable::visit_with(
                             $variant_arg, $visitor
                         )?;)*
-                        ::std::ops::ControlFlow::CONTINUE
+                        ::std::ops::ControlFlow::Continue(())
                     }
                     $($output)*
                 )
@@ -237,7 +237,7 @@ macro_rules! EnumTypeTraversalImpl {
                         $($crate::ty::visit::TypeVisitable::visit_with(
                             $variant_arg, $visitor
                         )?;)*
-                        ::std::ops::ControlFlow::CONTINUE
+                        ::std::ops::ControlFlow::Continue(())
                     }
                     $($output)*
                 )
@@ -251,7 +251,7 @@ macro_rules! EnumTypeTraversalImpl {
             @VisitVariants($this, $visitor)
                 input($($input)*)
                 output(
-                    $variant => { ::std::ops::ControlFlow::CONTINUE }
+                    $variant => { ::std::ops::ControlFlow::Continue(()) }
                     $($output)*
                 )
         )
diff --git a/compiler/rustc_middle/src/mir/basic_blocks.rs b/compiler/rustc_middle/src/mir/basic_blocks.rs
index 752cbdeae6b..b3354e6e9d2 100644
--- a/compiler/rustc_middle/src/mir/basic_blocks.rs
+++ b/compiler/rustc_middle/src/mir/basic_blocks.rs
@@ -1,38 +1,44 @@
-use crate::mir::graph_cyclic_cache::GraphIsCyclicCache;
-use crate::mir::predecessors::{PredecessorCache, Predecessors};
-use crate::mir::switch_sources::{SwitchSourceCache, SwitchSources};
-use crate::mir::traversal::PostorderCache;
-use crate::mir::{BasicBlock, BasicBlockData, Successors, START_BLOCK};
+use crate::mir::traversal::Postorder;
+use crate::mir::{BasicBlock, BasicBlockData, Successors, Terminator, TerminatorKind, START_BLOCK};
 
+use rustc_data_structures::fx::FxHashMap;
 use rustc_data_structures::graph;
 use rustc_data_structures::graph::dominators::{dominators, Dominators};
+use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
+use rustc_data_structures::sync::OnceCell;
 use rustc_index::vec::IndexVec;
+use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
+use smallvec::SmallVec;
 
 #[derive(Clone, TyEncodable, TyDecodable, Debug, HashStable, TypeFoldable, TypeVisitable)]
 pub struct BasicBlocks<'tcx> {
     basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>,
-    predecessor_cache: PredecessorCache,
-    switch_source_cache: SwitchSourceCache,
-    is_cyclic: GraphIsCyclicCache,
-    postorder_cache: PostorderCache,
+    cache: Cache,
+}
+
+// Typically 95%+ of basic blocks have 4 or fewer predecessors.
+pub type Predecessors = IndexVec<BasicBlock, SmallVec<[BasicBlock; 4]>>;
+
+pub type SwitchSources = FxHashMap<(BasicBlock, BasicBlock), SmallVec<[Option<u128>; 1]>>;
+
+#[derive(Clone, Default, Debug)]
+struct Cache {
+    predecessors: OnceCell<Predecessors>,
+    switch_sources: OnceCell<SwitchSources>,
+    is_cyclic: OnceCell<bool>,
+    postorder: OnceCell<Vec<BasicBlock>>,
 }
 
 impl<'tcx> BasicBlocks<'tcx> {
     #[inline]
     pub fn new(basic_blocks: IndexVec<BasicBlock, BasicBlockData<'tcx>>) -> Self {
-        BasicBlocks {
-            basic_blocks,
-            predecessor_cache: PredecessorCache::new(),
-            switch_source_cache: SwitchSourceCache::new(),
-            is_cyclic: GraphIsCyclicCache::new(),
-            postorder_cache: PostorderCache::new(),
-        }
+        BasicBlocks { basic_blocks, cache: Cache::default() }
     }
 
     /// Returns true if control-flow graph contains a cycle reachable from the `START_BLOCK`.
     #[inline]
     pub fn is_cfg_cyclic(&self) -> bool {
-        self.is_cyclic.is_cyclic(self)
+        *self.cache.is_cyclic.get_or_init(|| graph::is_cyclic(self))
     }
 
     #[inline]
@@ -43,20 +49,46 @@ impl<'tcx> BasicBlocks<'tcx> {
     /// Returns predecessors for each basic block.
     #[inline]
     pub fn predecessors(&self) -> &Predecessors {
-        self.predecessor_cache.compute(&self.basic_blocks)
+        self.cache.predecessors.get_or_init(|| {
+            let mut preds = IndexVec::from_elem(SmallVec::new(), &self.basic_blocks);
+            for (bb, data) in self.basic_blocks.iter_enumerated() {
+                if let Some(term) = &data.terminator {
+                    for succ in term.successors() {
+                        preds[succ].push(bb);
+                    }
+                }
+            }
+            preds
+        })
     }
 
     /// Returns basic blocks in a postorder.
     #[inline]
     pub fn postorder(&self) -> &[BasicBlock] {
-        self.postorder_cache.compute(&self.basic_blocks)
+        self.cache.postorder.get_or_init(|| {
+            Postorder::new(&self.basic_blocks, START_BLOCK).map(|(bb, _)| bb).collect()
+        })
     }
 
     /// `switch_sources()[&(target, switch)]` returns a list of switch
     /// values that lead to a `target` block from a `switch` block.
     #[inline]
     pub fn switch_sources(&self) -> &SwitchSources {
-        self.switch_source_cache.compute(&self.basic_blocks)
+        self.cache.switch_sources.get_or_init(|| {
+            let mut switch_sources: SwitchSources = FxHashMap::default();
+            for (bb, data) in self.basic_blocks.iter_enumerated() {
+                if let Some(Terminator {
+                    kind: TerminatorKind::SwitchInt { targets, .. }, ..
+                }) = &data.terminator
+                {
+                    for (value, target) in targets.iter() {
+                        switch_sources.entry((target, bb)).or_default().push(Some(value));
+                    }
+                    switch_sources.entry((targets.otherwise(), bb)).or_default().push(None);
+                }
+            }
+            switch_sources
+        })
     }
 
     /// Returns mutable reference to basic blocks. Invalidates CFG cache.
@@ -88,10 +120,7 @@ impl<'tcx> BasicBlocks<'tcx> {
     /// All other methods that allow you to mutate the basic blocks also call this method
     /// themselves, thereby avoiding any risk of accidentally cache invalidation.
     pub fn invalidate_cfg_cache(&mut self) {
-        self.predecessor_cache.invalidate();
-        self.switch_source_cache.invalidate();
-        self.is_cyclic.invalidate();
-        self.postorder_cache.invalidate();
+        self.cache = Cache::default();
     }
 }
 
@@ -145,3 +174,24 @@ impl<'tcx> graph::WithPredecessors for BasicBlocks<'tcx> {
         self.predecessors()[node].iter().copied()
     }
 }
+
+TrivialTypeTraversalAndLiftImpls! {
+    Cache,
+}
+
+impl<S: Encoder> Encodable<S> for Cache {
+    #[inline]
+    fn encode(&self, _s: &mut S) {}
+}
+
+impl<D: Decoder> Decodable<D> for Cache {
+    #[inline]
+    fn decode(_: &mut D) -> Self {
+        Default::default()
+    }
+}
+
+impl<CTX> HashStable<CTX> for Cache {
+    #[inline]
+    fn hash_stable(&self, _: &mut CTX, _: &mut StableHasher) {}
+}
diff --git a/compiler/rustc_middle/src/mir/graph_cyclic_cache.rs b/compiler/rustc_middle/src/mir/graph_cyclic_cache.rs
deleted file mode 100644
index f97bf2883b3..00000000000
--- a/compiler/rustc_middle/src/mir/graph_cyclic_cache.rs
+++ /dev/null
@@ -1,63 +0,0 @@
-use rustc_data_structures::graph::{
-    self, DirectedGraph, WithNumNodes, WithStartNode, WithSuccessors,
-};
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_data_structures::sync::OnceCell;
-use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
-
-/// Helper type to cache the result of `graph::is_cyclic`.
-#[derive(Clone, Debug)]
-pub(super) struct GraphIsCyclicCache {
-    cache: OnceCell<bool>,
-}
-
-impl GraphIsCyclicCache {
-    #[inline]
-    pub(super) fn new() -> Self {
-        GraphIsCyclicCache { cache: OnceCell::new() }
-    }
-
-    pub(super) fn is_cyclic<G>(&self, graph: &G) -> bool
-    where
-        G: ?Sized + DirectedGraph + WithStartNode + WithSuccessors + WithNumNodes,
-    {
-        *self.cache.get_or_init(|| graph::is_cyclic(graph))
-    }
-
-    /// Invalidates the cache.
-    #[inline]
-    pub(super) fn invalidate(&mut self) {
-        // Invalidating the cache requires mutating the MIR, which in turn requires a unique
-        // reference (`&mut`) to the `mir::Body`. Because of this, we can assume that all
-        // callers of `invalidate` have a unique reference to the MIR and thus to the
-        // cache. This means we never need to do synchronization when `invalidate` is called,
-        // we can simply reinitialize the `OnceCell`.
-        self.cache = OnceCell::new();
-    }
-}
-
-impl<S: Encoder> Encodable<S> for GraphIsCyclicCache {
-    #[inline]
-    fn encode(&self, s: &mut S) {
-        Encodable::encode(&(), s);
-    }
-}
-
-impl<D: Decoder> Decodable<D> for GraphIsCyclicCache {
-    #[inline]
-    fn decode(d: &mut D) -> Self {
-        let () = Decodable::decode(d);
-        Self::new()
-    }
-}
-
-impl<CTX> HashStable<CTX> for GraphIsCyclicCache {
-    #[inline]
-    fn hash_stable(&self, _: &mut CTX, _: &mut StableHasher) {
-        // do nothing
-    }
-}
-
-TrivialTypeTraversalAndLiftImpls! {
-    GraphIsCyclicCache,
-}
diff --git a/compiler/rustc_middle/src/mir/mod.rs b/compiler/rustc_middle/src/mir/mod.rs
index e52b243ecf6..d833286dc33 100644
--- a/compiler/rustc_middle/src/mir/mod.rs
+++ b/compiler/rustc_middle/src/mir/mod.rs
@@ -47,18 +47,15 @@ mod basic_blocks;
 pub mod coverage;
 mod generic_graph;
 pub mod generic_graphviz;
-mod graph_cyclic_cache;
 pub mod graphviz;
 pub mod interpret;
 pub mod mono;
 pub mod patch;
-mod predecessors;
 pub mod pretty;
 mod query;
 pub mod spanview;
 mod syntax;
 pub use syntax::*;
-mod switch_sources;
 pub mod tcx;
 pub mod terminator;
 pub use terminator::*;
diff --git a/compiler/rustc_middle/src/mir/predecessors.rs b/compiler/rustc_middle/src/mir/predecessors.rs
deleted file mode 100644
index 5f1fadaf3bc..00000000000
--- a/compiler/rustc_middle/src/mir/predecessors.rs
+++ /dev/null
@@ -1,78 +0,0 @@
-//! Lazily compute the reverse control-flow graph for the MIR.
-
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_data_structures::sync::OnceCell;
-use rustc_index::vec::IndexVec;
-use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
-use smallvec::SmallVec;
-
-use crate::mir::{BasicBlock, BasicBlockData};
-
-// Typically 95%+ of basic blocks have 4 or fewer predecessors.
-pub type Predecessors = IndexVec<BasicBlock, SmallVec<[BasicBlock; 4]>>;
-
-#[derive(Clone, Debug)]
-pub(super) struct PredecessorCache {
-    cache: OnceCell<Predecessors>,
-}
-
-impl PredecessorCache {
-    #[inline]
-    pub(super) fn new() -> Self {
-        PredecessorCache { cache: OnceCell::new() }
-    }
-
-    /// Invalidates the predecessor cache.
-    #[inline]
-    pub(super) fn invalidate(&mut self) {
-        // Invalidating the predecessor cache requires mutating the MIR, which in turn requires a
-        // unique reference (`&mut`) to the `mir::Body`. Because of this, we can assume that all
-        // callers of `invalidate` have a unique reference to the MIR and thus to the predecessor
-        // cache. This means we never need to do synchronization when `invalidate` is called, we can
-        // simply reinitialize the `OnceCell`.
-        self.cache = OnceCell::new();
-    }
-
-    /// Returns the predecessor graph for this MIR.
-    #[inline]
-    pub(super) fn compute(
-        &self,
-        basic_blocks: &IndexVec<BasicBlock, BasicBlockData<'_>>,
-    ) -> &Predecessors {
-        self.cache.get_or_init(|| {
-            let mut preds = IndexVec::from_elem(SmallVec::new(), basic_blocks);
-            for (bb, data) in basic_blocks.iter_enumerated() {
-                if let Some(term) = &data.terminator {
-                    for succ in term.successors() {
-                        preds[succ].push(bb);
-                    }
-                }
-            }
-
-            preds
-        })
-    }
-}
-
-impl<S: Encoder> Encodable<S> for PredecessorCache {
-    #[inline]
-    fn encode(&self, _s: &mut S) {}
-}
-
-impl<D: Decoder> Decodable<D> for PredecessorCache {
-    #[inline]
-    fn decode(_: &mut D) -> Self {
-        Self::new()
-    }
-}
-
-impl<CTX> HashStable<CTX> for PredecessorCache {
-    #[inline]
-    fn hash_stable(&self, _: &mut CTX, _: &mut StableHasher) {
-        // do nothing
-    }
-}
-
-TrivialTypeTraversalAndLiftImpls! {
-    PredecessorCache,
-}
diff --git a/compiler/rustc_middle/src/mir/switch_sources.rs b/compiler/rustc_middle/src/mir/switch_sources.rs
deleted file mode 100644
index b91c0c25782..00000000000
--- a/compiler/rustc_middle/src/mir/switch_sources.rs
+++ /dev/null
@@ -1,78 +0,0 @@
-//! Lazily compute the inverse of each `SwitchInt`'s switch targets. Modeled after
-//! `Predecessors`/`PredecessorCache`.
-
-use rustc_data_structures::fx::FxHashMap;
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_data_structures::sync::OnceCell;
-use rustc_index::vec::IndexVec;
-use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
-use smallvec::SmallVec;
-
-use crate::mir::{BasicBlock, BasicBlockData, Terminator, TerminatorKind};
-
-pub type SwitchSources = FxHashMap<(BasicBlock, BasicBlock), SmallVec<[Option<u128>; 1]>>;
-
-#[derive(Clone, Debug)]
-pub(super) struct SwitchSourceCache {
-    cache: OnceCell<SwitchSources>,
-}
-
-impl SwitchSourceCache {
-    #[inline]
-    pub(super) fn new() -> Self {
-        SwitchSourceCache { cache: OnceCell::new() }
-    }
-
-    /// Invalidates the switch source cache.
-    #[inline]
-    pub(super) fn invalidate(&mut self) {
-        self.cache = OnceCell::new();
-    }
-
-    /// Returns the switch sources for this MIR.
-    #[inline]
-    pub(super) fn compute(
-        &self,
-        basic_blocks: &IndexVec<BasicBlock, BasicBlockData<'_>>,
-    ) -> &SwitchSources {
-        self.cache.get_or_init(|| {
-            let mut switch_sources: SwitchSources = FxHashMap::default();
-            for (bb, data) in basic_blocks.iter_enumerated() {
-                if let Some(Terminator {
-                    kind: TerminatorKind::SwitchInt { targets, .. }, ..
-                }) = &data.terminator
-                {
-                    for (value, target) in targets.iter() {
-                        switch_sources.entry((target, bb)).or_default().push(Some(value));
-                    }
-                    switch_sources.entry((targets.otherwise(), bb)).or_default().push(None);
-                }
-            }
-
-            switch_sources
-        })
-    }
-}
-
-impl<S: Encoder> Encodable<S> for SwitchSourceCache {
-    #[inline]
-    fn encode(&self, _s: &mut S) {}
-}
-
-impl<D: Decoder> Decodable<D> for SwitchSourceCache {
-    #[inline]
-    fn decode(_: &mut D) -> Self {
-        Self::new()
-    }
-}
-
-impl<CTX> HashStable<CTX> for SwitchSourceCache {
-    #[inline]
-    fn hash_stable(&self, _: &mut CTX, _: &mut StableHasher) {
-        // do nothing
-    }
-}
-
-TrivialTypeTraversalAndLiftImpls! {
-    SwitchSourceCache,
-}
diff --git a/compiler/rustc_middle/src/mir/syntax.rs b/compiler/rustc_middle/src/mir/syntax.rs
index 6b4489026d3..52c2b10cbbe 100644
--- a/compiler/rustc_middle/src/mir/syntax.rs
+++ b/compiler/rustc_middle/src/mir/syntax.rs
@@ -512,6 +512,16 @@ pub struct CopyNonOverlapping<'tcx> {
 ///     must also be `cleanup`. This is a part of the type system and checked statically, so it is
 ///     still an error to have such an edge in the CFG even if it's known that it won't be taken at
 ///     runtime.
+///  4. The control flow between cleanup blocks must look like an upside down tree. Roughly
+///     speaking, this means that control flow that looks like a V is allowed, while control flow
+///     that looks like a W is not. This is necessary to ensure that landing pad information can be
+///     correctly codegened on MSVC. More precisely:
+///
+///     Begin with the standard control flow graph `G`. Modify `G` as follows: for any two cleanup
+///     vertices `u` and `v` such that `u` dominates `v`, contract `u` and `v` into a single vertex,
+///     deleting self edges and duplicate edges in the process. Now remove all vertices from `G`
+///     that are not cleanup vertices or are not reachable. The resulting graph must be an inverted
+///     tree, that is each vertex may have at most one successor and there may be no cycles.
 #[derive(Clone, TyEncodable, TyDecodable, Hash, HashStable, PartialEq, TypeFoldable, TypeVisitable)]
 pub enum TerminatorKind<'tcx> {
     /// Block has one successor; we continue execution there.
diff --git a/compiler/rustc_middle/src/mir/traversal.rs b/compiler/rustc_middle/src/mir/traversal.rs
index 0b461d1ce41..f37222cb297 100644
--- a/compiler/rustc_middle/src/mir/traversal.rs
+++ b/compiler/rustc_middle/src/mir/traversal.rs
@@ -1,7 +1,4 @@
-use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
-use rustc_data_structures::sync::OnceCell;
 use rustc_index::bit_set::BitSet;
-use rustc_serialize::{Decodable, Decoder, Encodable, Encoder};
 
 use super::*;
 
@@ -339,50 +336,3 @@ pub fn reverse_postorder<'a, 'tcx>(body: &'a Body<'tcx>) -> ReversePostorderIter
     let len = blocks.len();
     ReversePostorderIter { body, blocks, idx: len }
 }
-
-#[derive(Clone, Debug)]
-pub(super) struct PostorderCache {
-    cache: OnceCell<Vec<BasicBlock>>,
-}
-
-impl PostorderCache {
-    #[inline]
-    pub(super) fn new() -> Self {
-        PostorderCache { cache: OnceCell::new() }
-    }
-
-    /// Invalidates the postorder cache.
-    #[inline]
-    pub(super) fn invalidate(&mut self) {
-        self.cache = OnceCell::new();
-    }
-
-    /// Returns the `&[BasicBlocks]` represents the postorder graph for this MIR.
-    #[inline]
-    pub(super) fn compute(&self, body: &IndexVec<BasicBlock, BasicBlockData<'_>>) -> &[BasicBlock] {
-        self.cache.get_or_init(|| Postorder::new(body, START_BLOCK).map(|(bb, _)| bb).collect())
-    }
-}
-
-impl<S: Encoder> Encodable<S> for PostorderCache {
-    #[inline]
-    fn encode(&self, _s: &mut S) {}
-}
-
-impl<D: Decoder> Decodable<D> for PostorderCache {
-    #[inline]
-    fn decode(_: &mut D) -> Self {
-        Self::new()
-    }
-}
-
-impl<CTX> HashStable<CTX> for PostorderCache {
-    #[inline]
-    fn hash_stable(&self, _: &mut CTX, _: &mut StableHasher) {
-        // do nothing
-    }
-}
-
-TrivialTypeTraversalAndLiftImpls! {
-    PostorderCache,
-}
diff --git a/compiler/rustc_middle/src/mir/type_visitable.rs b/compiler/rustc_middle/src/mir/type_visitable.rs
index e7cd497b206..d44c6809bd8 100644
--- a/compiler/rustc_middle/src/mir/type_visitable.rs
+++ b/compiler/rustc_middle/src/mir/type_visitable.rs
@@ -4,6 +4,6 @@ use super::*;
 
 impl<'tcx, R: Idx, C: Idx> TypeVisitable<'tcx> for BitMatrix<R, C> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, _: &mut V) -> ControlFlow<V::BreakTy> {
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
diff --git a/compiler/rustc_middle/src/query/mod.rs b/compiler/rustc_middle/src/query/mod.rs
index b3acf815e0c..6bbf7fa3914 100644
--- a/compiler/rustc_middle/src/query/mod.rs
+++ b/compiler/rustc_middle/src/query/mod.rs
@@ -177,6 +177,12 @@ rustc_queries! {
         separate_provide_extern
     }
 
+    query is_type_alias_impl_trait(key: DefId) -> bool
+    {
+        desc { "determine whether the opaque is a type-alias impl trait" }
+        separate_provide_extern
+    }
+
     query analysis(key: ()) -> Result<(), ErrorGuaranteed> {
         eval_always
         desc { "running analysis passes on this crate" }
@@ -272,7 +278,7 @@ rustc_queries! {
     /// ```
     ///
     /// Bounds from the parent (e.g. with nested impl trait) are not included.
-    query item_bounds(key: DefId) -> &'tcx ty::List<ty::Predicate<'tcx>> {
+    query item_bounds(key: DefId) -> ty::EarlyBinder<&'tcx ty::List<ty::Predicate<'tcx>>> {
         desc { |tcx| "elaborating item bounds for `{}`", tcx.def_path_str(key) }
     }
 
diff --git a/compiler/rustc_middle/src/traits/chalk.rs b/compiler/rustc_middle/src/traits/chalk.rs
index dd75b0d9ebc..fcc8f457a8b 100644
--- a/compiler/rustc_middle/src/traits/chalk.rs
+++ b/compiler/rustc_middle/src/traits/chalk.rs
@@ -159,18 +159,20 @@ impl<'tcx> chalk_ir::interner::Interner for RustInterner<'tcx> {
             }
             chalk_ir::TyKind::Array(ty, len) => Some(write!(fmt, "[{:?}; {:?}]", ty, len)),
             chalk_ir::TyKind::Slice(ty) => Some(write!(fmt, "[{:?}]", ty)),
-            chalk_ir::TyKind::Tuple(len, substs) => Some((|| {
-                write!(fmt, "(")?;
-                for (idx, substitution) in substs.interned().iter().enumerate() {
-                    if idx == *len && *len != 1 {
-                        // Don't add a trailing comma if the tuple has more than one element
-                        write!(fmt, "{:?}", substitution)?;
-                    } else {
-                        write!(fmt, "{:?},", substitution)?;
+            chalk_ir::TyKind::Tuple(len, substs) => Some(
+                try {
+                    write!(fmt, "(")?;
+                    for (idx, substitution) in substs.interned().iter().enumerate() {
+                        if idx == *len && *len != 1 {
+                            // Don't add a trailing comma if the tuple has more than one element
+                            write!(fmt, "{:?}", substitution)?;
+                        } else {
+                            write!(fmt, "{:?},", substitution)?;
+                        }
                     }
-                }
-                write!(fmt, ")")
-            })()),
+                    write!(fmt, ")")?;
+                },
+            ),
             _ => None,
         }
     }
diff --git a/compiler/rustc_middle/src/traits/query.rs b/compiler/rustc_middle/src/traits/query.rs
index 543f5b87e00..615154a55e5 100644
--- a/compiler/rustc_middle/src/traits/query.rs
+++ b/compiler/rustc_middle/src/traits/query.rs
@@ -8,9 +8,8 @@
 use crate::error::DropCheckOverflow;
 use crate::infer::canonical::{Canonical, QueryResponse};
 use crate::ty::error::TypeError;
-use crate::ty::subst::{GenericArg, SubstsRef};
+use crate::ty::subst::GenericArg;
 use crate::ty::{self, Ty, TyCtxt};
-use rustc_hir::def_id::DefId;
 use rustc_span::source_map::Span;
 
 pub mod type_op {
@@ -214,6 +213,5 @@ pub struct NormalizationResult<'tcx> {
 pub enum OutlivesBound<'tcx> {
     RegionSubRegion(ty::Region<'tcx>, ty::Region<'tcx>),
     RegionSubParam(ty::Region<'tcx>, ty::ParamTy),
-    RegionSubProjection(ty::Region<'tcx>, ty::AliasTy<'tcx>),
-    RegionSubOpaque(ty::Region<'tcx>, DefId, SubstsRef<'tcx>),
+    RegionSubAlias(ty::Region<'tcx>, ty::AliasTy<'tcx>),
 }
diff --git a/compiler/rustc_middle/src/ty/assoc.rs b/compiler/rustc_middle/src/ty/assoc.rs
index 859a58c8998..bb7fba3ee71 100644
--- a/compiler/rustc_middle/src/ty/assoc.rs
+++ b/compiler/rustc_middle/src/ty/assoc.rs
@@ -37,6 +37,11 @@ impl AssocItem {
         Ident::new(self.name, tcx.def_ident_span(self.def_id).unwrap())
     }
 
+    /// Gets the defaultness of the associated item.
+    /// To get the default associated type, use the [`type_of`] query on the
+    /// [`DefId`] of the type.
+    ///
+    /// [`type_of`]: crate::ty::TyCtxt::type_of
     pub fn defaultness(&self, tcx: TyCtxt<'_>) -> hir::Defaultness {
         tcx.impl_defaultness(self.def_id)
     }
diff --git a/compiler/rustc_middle/src/ty/context.rs b/compiler/rustc_middle/src/ty/context.rs
index 0c66443555f..ce04d8d21f4 100644
--- a/compiler/rustc_middle/src/ty/context.rs
+++ b/compiler/rustc_middle/src/ty/context.rs
@@ -1952,6 +1952,15 @@ impl<'tcx> TyCtxt<'tcx> {
         self.mk_ty(GeneratorWitness(types))
     }
 
+    /// Creates a `&mut Context<'_>` [`Ty`] with erased lifetimes.
+    pub fn mk_task_context(self) -> Ty<'tcx> {
+        let context_did = self.require_lang_item(LangItem::Context, None);
+        let context_adt_ref = self.adt_def(context_did);
+        let context_substs = self.intern_substs(&[self.lifetimes.re_erased.into()]);
+        let context_ty = self.mk_adt(context_adt_ref, context_substs);
+        self.mk_mut_ref(self.lifetimes.re_erased, context_ty)
+    }
+
     #[inline]
     pub fn mk_ty_var(self, v: TyVid) -> Ty<'tcx> {
         self.mk_ty_infer(TyVar(v))
diff --git a/compiler/rustc_middle/src/ty/diagnostics.rs b/compiler/rustc_middle/src/ty/diagnostics.rs
index 8c22df7395f..4b4518f61e8 100644
--- a/compiler/rustc_middle/src/ty/diagnostics.rs
+++ b/compiler/rustc_middle/src/ty/diagnostics.rs
@@ -4,12 +4,13 @@ use std::ops::ControlFlow;
 
 use crate::ty::{
     visit::TypeVisitable, AliasTy, Const, ConstKind, DefIdTree, InferConst, InferTy, Opaque,
-    PolyTraitPredicate, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor,
+    PolyTraitPredicate, Projection, Ty, TyCtxt, TypeSuperVisitable, TypeVisitor,
 };
 
 use rustc_data_structures::fx::FxHashMap;
 use rustc_errors::{Applicability, Diagnostic, DiagnosticArgValue, IntoDiagnosticArg};
 use rustc_hir as hir;
+use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
 use rustc_hir::WherePredicate;
 use rustc_span::Span;
@@ -17,7 +18,7 @@ use rustc_type_ir::sty::TyKind::*;
 
 impl<'tcx> IntoDiagnosticArg for Ty<'tcx> {
     fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
-        format!("{}", self).into_diagnostic_arg()
+        self.to_string().into_diagnostic_arg()
     }
 }
 
@@ -443,7 +444,7 @@ impl<'tcx> TypeVisitor<'tcx> for IsSuggestableVisitor<'tcx> {
     type BreakTy = ();
 
     fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
-        match t.kind() {
+        match *t.kind() {
             Infer(InferTy::TyVar(_)) if self.infer_suggestable => {}
 
             FnDef(..)
@@ -458,9 +459,9 @@ impl<'tcx> TypeVisitor<'tcx> for IsSuggestableVisitor<'tcx> {
             }
 
             Alias(Opaque, AliasTy { def_id, .. }) => {
-                let parent = self.tcx.parent(*def_id);
-                if let hir::def::DefKind::TyAlias | hir::def::DefKind::AssocTy = self.tcx.def_kind(parent)
-                    && let Alias(Opaque, AliasTy { def_id: parent_opaque_def_id, .. }) = self.tcx.type_of(parent).kind()
+                let parent = self.tcx.parent(def_id);
+                if let DefKind::TyAlias | DefKind::AssocTy = self.tcx.def_kind(parent)
+                    && let Alias(Opaque, AliasTy { def_id: parent_opaque_def_id, .. }) = *self.tcx.type_of(parent).kind()
                     && parent_opaque_def_id == def_id
                 {
                     // Okay
@@ -469,6 +470,12 @@ impl<'tcx> TypeVisitor<'tcx> for IsSuggestableVisitor<'tcx> {
                 }
             }
 
+            Alias(Projection, AliasTy { def_id, .. }) => {
+                if self.tcx.def_kind(def_id) != DefKind::AssocTy {
+                    return ControlFlow::Break(());
+                }
+            }
+
             Param(param) => {
                 // FIXME: It would be nice to make this not use string manipulation,
                 // but it's pretty hard to do this, since `ty::ParamTy` is missing
diff --git a/compiler/rustc_middle/src/ty/generics.rs b/compiler/rustc_middle/src/ty/generics.rs
index 8a5e765b9a3..801ca600445 100644
--- a/compiler/rustc_middle/src/ty/generics.rs
+++ b/compiler/rustc_middle/src/ty/generics.rs
@@ -341,15 +341,9 @@ impl<'tcx> GenericPredicates<'tcx> {
         &self,
         tcx: TyCtxt<'tcx>,
         substs: SubstsRef<'tcx>,
-    ) -> InstantiatedPredicates<'tcx> {
-        InstantiatedPredicates {
-            predicates: self
-                .predicates
-                .iter()
-                .map(|(p, _)| EarlyBinder(*p).subst(tcx, substs))
-                .collect(),
-            spans: self.predicates.iter().map(|(_, sp)| *sp).collect(),
-        }
+    ) -> impl Iterator<Item = (Predicate<'tcx>, Span)> + DoubleEndedIterator + ExactSizeIterator
+    {
+        EarlyBinder(self.predicates).subst_iter_copied(tcx, substs)
     }
 
     #[instrument(level = "debug", skip(self, tcx))]
diff --git a/compiler/rustc_middle/src/ty/mod.rs b/compiler/rustc_middle/src/ty/mod.rs
index 0a0a8a5a66a..7dfcd1bb507 100644
--- a/compiler/rustc_middle/src/ty/mod.rs
+++ b/compiler/rustc_middle/src/ty/mod.rs
@@ -28,7 +28,6 @@ use crate::ty::util::Discr;
 pub use adt::*;
 pub use assoc::*;
 pub use generics::*;
-use hir::OpaqueTyOrigin;
 use rustc_ast as ast;
 use rustc_ast::node_id::NodeMap;
 use rustc_attr as attr;
@@ -39,7 +38,7 @@ use rustc_data_structures::stable_hasher::{HashStable, StableHasher};
 use rustc_data_structures::tagged_ptr::CopyTaggedPtr;
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, CtorOf, DefKind, LifetimeRes, Res};
-use rustc_hir::def_id::{CrateNum, DefId, LocalDefId, LocalDefIdMap};
+use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, LocalDefId, LocalDefIdMap};
 use rustc_hir::Node;
 use rustc_index::vec::IndexVec;
 use rustc_macros::HashStable;
@@ -437,7 +436,7 @@ pub struct CrateVariancesMap<'tcx> {
     /// For each item with generics, maps to a vector of the variance
     /// of its generics. If an item has no generics, it will have no
     /// entry.
-    pub variances: FxHashMap<DefId, &'tcx [ty::Variance]>,
+    pub variances: DefIdMap<&'tcx [ty::Variance]>,
 }
 
 // Contains information needed to resolve types and (in the future) look up
@@ -1252,6 +1251,35 @@ impl<'tcx> InstantiatedPredicates<'tcx> {
     pub fn is_empty(&self) -> bool {
         self.predicates.is_empty()
     }
+
+    pub fn iter(&self) -> <&Self as IntoIterator>::IntoIter {
+        (&self).into_iter()
+    }
+}
+
+impl<'tcx> IntoIterator for InstantiatedPredicates<'tcx> {
+    type Item = (Predicate<'tcx>, Span);
+
+    type IntoIter = std::iter::Zip<std::vec::IntoIter<Predicate<'tcx>>, std::vec::IntoIter<Span>>;
+
+    fn into_iter(self) -> Self::IntoIter {
+        debug_assert_eq!(self.predicates.len(), self.spans.len());
+        std::iter::zip(self.predicates, self.spans)
+    }
+}
+
+impl<'a, 'tcx> IntoIterator for &'a InstantiatedPredicates<'tcx> {
+    type Item = (Predicate<'tcx>, Span);
+
+    type IntoIter = std::iter::Zip<
+        std::iter::Copied<std::slice::Iter<'a, Predicate<'tcx>>>,
+        std::iter::Copied<std::slice::Iter<'a, Span>>,
+    >;
+
+    fn into_iter(self) -> Self::IntoIter {
+        debug_assert_eq!(self.predicates.len(), self.spans.len());
+        std::iter::zip(self.predicates.iter().copied(), self.spans.iter().copied())
+    }
 }
 
 #[derive(Copy, Clone, Debug, PartialEq, Eq, Hash, HashStable, TyEncodable, TyDecodable, Lift)]
@@ -1316,7 +1344,6 @@ impl<'tcx> OpaqueHiddenType<'tcx> {
         tcx: TyCtxt<'tcx>,
         // typeck errors have subpar spans for opaque types, so delay error reporting until borrowck.
         ignore_errors: bool,
-        origin: OpaqueTyOrigin,
     ) -> Self {
         let OpaqueTypeKey { def_id, substs } = opaque_type_key;
 
@@ -1332,30 +1359,7 @@ impl<'tcx> OpaqueHiddenType<'tcx> {
         // This zip may have several times the same lifetime in `substs` paired with a different
         // lifetime from `id_substs`. Simply `collect`ing the iterator is the correct behaviour:
         // it will pick the last one, which is the one we introduced in the impl-trait desugaring.
-        let map = substs.iter().zip(id_substs);
-
-        let map: FxHashMap<GenericArg<'tcx>, GenericArg<'tcx>> = match origin {
-            // HACK: The HIR lowering for async fn does not generate
-            // any `+ Captures<'x>` bounds for the `impl Future<...>`, so all async fns with lifetimes
-            // would now fail to compile. We should probably just make hir lowering fill this in properly.
-            OpaqueTyOrigin::AsyncFn(_) => map.collect(),
-            OpaqueTyOrigin::FnReturn(_) | OpaqueTyOrigin::TyAlias => {
-                // Opaque types may only use regions that are bound. So for
-                // ```rust
-                // type Foo<'a, 'b, 'c> = impl Trait<'a> + 'b;
-                // ```
-                // we may not use `'c` in the hidden type.
-                let variances = tcx.variances_of(def_id);
-                debug!(?variances);
-
-                map.filter(|(_, v)| {
-                    let ty::GenericArgKind::Lifetime(lt) = v.unpack() else { return true };
-                    let ty::ReEarlyBound(ebr) = lt.kind() else { bug!() };
-                    variances[ebr.index as usize] == ty::Variance::Invariant
-                })
-                .collect()
-            }
-        };
+        let map = substs.iter().zip(id_substs).collect();
         debug!("map = {:#?}", map);
 
         // Convert the type from the function into a type valid outside
@@ -2353,6 +2357,11 @@ impl<'tcx> TyCtxt<'tcx> {
         self.trait_def(trait_def_id).has_auto_impl
     }
 
+    /// Returns `true` if this is a trait alias.
+    pub fn trait_is_alias(self, trait_def_id: DefId) -> bool {
+        self.def_kind(trait_def_id) == DefKind::TraitAlias
+    }
+
     pub fn trait_is_coinductive(self, trait_def_id: DefId) -> bool {
         self.trait_is_auto(trait_def_id) || self.lang_items().sized_trait() == Some(trait_def_id)
     }
diff --git a/compiler/rustc_middle/src/ty/parameterized.rs b/compiler/rustc_middle/src/ty/parameterized.rs
index e32a7ee1c35..24f3d1acff1 100644
--- a/compiler/rustc_middle/src/ty/parameterized.rs
+++ b/compiler/rustc_middle/src/ty/parameterized.rs
@@ -52,6 +52,7 @@ trivially_parameterized_over_tcx! {
     usize,
     (),
     u32,
+    bool,
     std::string::String,
     crate::metadata::ModChild,
     crate::middle::codegen_fn_attrs::CodegenFnAttrs,
diff --git a/compiler/rustc_middle/src/ty/print/pretty.rs b/compiler/rustc_middle/src/ty/print/pretty.rs
index 42fc78a4715..ae7c20fff0c 100644
--- a/compiler/rustc_middle/src/ty/print/pretty.rs
+++ b/compiler/rustc_middle/src/ty/print/pretty.rs
@@ -393,7 +393,7 @@ pub trait PrettyPrinter<'tcx>:
         match self.tcx().trimmed_def_paths(()).get(&def_id) {
             None => Ok((self, false)),
             Some(symbol) => {
-                self.write_str(symbol.as_str())?;
+                write!(self, "{}", Ident::with_dummy_span(*symbol))?;
                 Ok((self, true))
             }
         }
@@ -854,24 +854,7 @@ pub trait PrettyPrinter<'tcx>:
                 }
                 p!("]");
             }
-            ty::Array(ty, sz) => {
-                p!("[", print(ty), "; ");
-                if self.should_print_verbose() {
-                    p!(write("{:?}", sz));
-                } else if let ty::ConstKind::Unevaluated(..) = sz.kind() {
-                    // Do not try to evaluate unevaluated constants. If we are const evaluating an
-                    // array length anon const, rustc will (with debug assertions) print the
-                    // constant's path. Which will end up here again.
-                    p!("_");
-                } else if let Some(n) = sz.kind().try_to_bits(self.tcx().data_layout.pointer_size) {
-                    p!(write("{}", n));
-                } else if let ty::ConstKind::Param(param) = sz.kind() {
-                    p!(print(param));
-                } else {
-                    p!("_");
-                }
-                p!("]")
-            }
+            ty::Array(ty, sz) => p!("[", print(ty), "; ", print(sz), "]"),
             ty::Slice(ty) => p!("[", print(ty), "]"),
         }
 
@@ -1303,21 +1286,25 @@ pub trait PrettyPrinter<'tcx>:
         match ct.kind() {
             ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs }) => {
                 match self.tcx().def_kind(def.did) {
-                    DefKind::Static(..) | DefKind::Const | DefKind::AssocConst => {
+                    DefKind::Const | DefKind::AssocConst => {
                         p!(print_value_path(def.did, substs))
                     }
-                    _ => {
-                        if def.is_local() {
-                            let span = self.tcx().def_span(def.did);
-                            if let Ok(snip) = self.tcx().sess.source_map().span_to_snippet(span) {
-                                p!(write("{}", snip))
-                            } else {
-                                print_underscore!()
-                            }
+                    DefKind::AnonConst => {
+                        if def.is_local()
+                            && let span = self.tcx().def_span(def.did)
+                            && let Ok(snip) = self.tcx().sess.source_map().span_to_snippet(span)
+                        {
+                            p!(write("{}", snip))
                         } else {
-                            print_underscore!()
+                            // Do not call `print_value_path` as if a parent of this anon const is an impl it will
+                            // attempt to print out the impl trait ref i.e. `<T as Trait>::{constant#0}`. This would
+                            // cause printing to enter an infinite recursion if the anon const is in the self type i.e.
+                            // `impl<T: Default> Default for [T; 32 - 1 - 1 - 1] {`
+                            // where we would try to print `<[T; /* print `constant#0` again */] as Default>::{constant#0}`
+                            p!(write("{}::{}", self.tcx().crate_name(def.did.krate), self.tcx().def_path(def.did).to_string_no_crate_verbose()))
                         }
                     }
+                    defkind => bug!("`{:?}` has unexpcted defkind {:?}", ct, defkind),
                 }
             }
             ty::ConstKind::Infer(infer_ct) => {
@@ -1339,7 +1326,7 @@ pub trait PrettyPrinter<'tcx>:
             ty::ConstKind::Placeholder(placeholder) => p!(write("Placeholder({:?})", placeholder)),
             // FIXME(generic_const_exprs):
             // write out some legible representation of an abstract const?
-            ty::ConstKind::Expr(_) => p!("[Const Expr]"),
+            ty::ConstKind::Expr(_) => p!("[const expr]"),
             ty::ConstKind::Error(_) => p!("[const error]"),
         };
         Ok(self)
@@ -2481,7 +2468,7 @@ impl<'tcx> FmtPrinter<'_, 'tcx> {
                 if not_previously_inserted {
                     ty.super_visit_with(self)
                 } else {
-                    ControlFlow::CONTINUE
+                    ControlFlow::Continue(())
                 }
             }
         }
diff --git a/compiler/rustc_middle/src/ty/structural_impls.rs b/compiler/rustc_middle/src/ty/structural_impls.rs
index 7c5563ac1ae..7d4d35b7fdf 100644
--- a/compiler/rustc_middle/src/ty/structural_impls.rs
+++ b/compiler/rustc_middle/src/ty/structural_impls.rs
@@ -7,7 +7,7 @@ use crate::mir::{Field, ProjectionKind};
 use crate::ty::fold::{FallibleTypeFolder, TypeFoldable, TypeSuperFoldable};
 use crate::ty::print::{with_no_trimmed_paths, FmtPrinter, Printer};
 use crate::ty::visit::{TypeSuperVisitable, TypeVisitable, TypeVisitor};
-use crate::ty::{self, InferConst, Lift, Term, TermKind, Ty, TyCtxt};
+use crate::ty::{self, AliasTy, InferConst, Lift, Term, TermKind, Ty, TyCtxt};
 use rustc_data_structures::functor::IdFunctor;
 use rustc_hir::def::Namespace;
 use rustc_index::vec::{Idx, IndexVec};
@@ -180,6 +180,15 @@ impl<'tcx> fmt::Debug for ty::PredicateKind<'tcx> {
     }
 }
 
+impl<'tcx> fmt::Debug for AliasTy<'tcx> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct("AliasTy")
+            .field("substs", &self.substs)
+            .field("def_id", &self.def_id)
+            .finish()
+    }
+}
+
 ///////////////////////////////////////////////////////////////////////////
 // Atomic structs
 //
@@ -227,6 +236,7 @@ TrivialTypeTraversalAndLiftImpls! {
     crate::ty::BoundRegionKind,
     crate::ty::AssocItem,
     crate::ty::AssocKind,
+    crate::ty::AliasKind,
     crate::ty::Placeholder<crate::ty::BoundRegionKind>,
     crate::ty::ClosureKind,
     crate::ty::FreeRegion,
@@ -357,7 +367,7 @@ impl<'tcx> TypeFoldable<'tcx> for ty::AdtDef<'tcx> {
 
 impl<'tcx> TypeVisitable<'tcx> for ty::AdtDef<'tcx> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, _visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
 
@@ -704,7 +714,7 @@ impl<'tcx> TypeSuperVisitable<'tcx> for Ty<'tcx> {
             | ty::Placeholder(..)
             | ty::Param(..)
             | ty::Never
-            | ty::Foreign(..) => ControlFlow::CONTINUE,
+            | ty::Foreign(..) => ControlFlow::Continue(()),
         }
     }
 }
@@ -732,7 +742,7 @@ impl<'tcx> TypeSuperFoldable<'tcx> for ty::Region<'tcx> {
 
 impl<'tcx> TypeSuperVisitable<'tcx> for ty::Region<'tcx> {
     fn super_visit_with<V: TypeVisitor<'tcx>>(&self, _visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
 
@@ -834,7 +844,7 @@ impl<'tcx> TypeFoldable<'tcx> for InferConst<'tcx> {
 
 impl<'tcx> TypeVisitable<'tcx> for InferConst<'tcx> {
     fn visit_with<V: TypeVisitor<'tcx>>(&self, _visitor: &mut V) -> ControlFlow<V::BreakTy> {
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
 
diff --git a/compiler/rustc_middle/src/ty/sty.rs b/compiler/rustc_middle/src/ty/sty.rs
index b5bb9238512..6a7b23e40a7 100644
--- a/compiler/rustc_middle/src/ty/sty.rs
+++ b/compiler/rustc_middle/src/ty/sty.rs
@@ -100,6 +100,13 @@ impl BoundRegionKind {
 
         None
     }
+
+    pub fn get_id(&self) -> Option<DefId> {
+        match *self {
+            BoundRegionKind::BrNamed(id, _) => return Some(id),
+            _ => None,
+        }
+    }
 }
 
 pub trait Article {
@@ -1106,17 +1113,6 @@ impl<'tcx, T> Binder<'tcx, T> {
         if self.0.has_escaping_bound_vars() { None } else { Some(self.skip_binder()) }
     }
 
-    pub fn no_bound_vars_ignoring_escaping(self, tcx: TyCtxt<'tcx>) -> Option<T>
-    where
-        T: TypeFoldable<'tcx>,
-    {
-        if !self.0.has_escaping_bound_vars() {
-            Some(self.skip_binder())
-        } else {
-            self.0.try_fold_with(&mut SkipBindersAt { index: ty::INNERMOST, tcx }).ok()
-        }
-    }
-
     /// Splits the contents into two things that share the same binder
     /// level as the original, returning two distinct binders.
     ///
@@ -1226,7 +1222,7 @@ impl<'tcx> FallibleTypeFolder<'tcx> for SkipBindersAt<'tcx> {
 /// For a projection, this would be `<Ty as Trait<...>>::N`.
 ///
 /// For an opaque type, there is no explicit syntax.
-#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug, TyEncodable, TyDecodable)]
+#[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, TyEncodable, TyDecodable)]
 #[derive(HashStable, TypeFoldable, TypeVisitable, Lift)]
 pub struct AliasTy<'tcx> {
     /// The parameters of the associated or opaque item.
@@ -1249,19 +1245,34 @@ pub struct AliasTy<'tcx> {
     /// aka. `tcx.parent(def_id)`.
     pub def_id: DefId,
 
-    /// This field exists to prevent the creation of `ProjectionTy` without using
+    /// This field exists to prevent the creation of `AliasTy` without using
     /// [TyCtxt::mk_alias_ty].
     pub(super) _use_mk_alias_ty_instead: (),
 }
 
 impl<'tcx> AliasTy<'tcx> {
+    pub fn kind(self, tcx: TyCtxt<'tcx>) -> ty::AliasKind {
+        match tcx.def_kind(self.def_id) {
+            DefKind::AssocTy | DefKind::ImplTraitPlaceholder => ty::Projection,
+            DefKind::OpaqueTy => ty::Opaque,
+            kind => bug!("unexpected DefKind in AliasTy: {kind:?}"),
+        }
+    }
+
+    pub fn to_ty(self, tcx: TyCtxt<'tcx>) -> Ty<'tcx> {
+        tcx.mk_ty(ty::Alias(self.kind(tcx), self))
+    }
+}
+
+/// The following methods work only with associated type projections.
+impl<'tcx> AliasTy<'tcx> {
     pub fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId {
         match tcx.def_kind(self.def_id) {
             DefKind::AssocTy | DefKind::AssocConst => tcx.parent(self.def_id),
             DefKind::ImplTraitPlaceholder => {
                 tcx.parent(tcx.impl_trait_in_trait_parent(self.def_id))
             }
-            kind => bug!("unexpected DefKind in ProjectionTy: {kind:?}"),
+            kind => bug!("expected a projection AliasTy; found {kind:?}"),
         }
     }
 
@@ -2015,7 +2026,7 @@ impl<'tcx> Ty<'tcx> {
             type BreakTy = ();
 
             fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
-                if self.0 == t { ControlFlow::BREAK } else { t.super_visit_with(self) }
+                if self.0 == t { ControlFlow::Break(()) } else { t.super_visit_with(self) }
             }
         }
 
diff --git a/compiler/rustc_middle/src/ty/subst.rs b/compiler/rustc_middle/src/ty/subst.rs
index 8f764011d0a..a07582fc8ff 100644
--- a/compiler/rustc_middle/src/ty/subst.rs
+++ b/compiler/rustc_middle/src/ty/subst.rs
@@ -7,6 +7,7 @@ use crate::ty::visit::{TypeVisitable, TypeVisitor};
 use crate::ty::{self, Lift, List, ParamConst, Ty, TyCtxt};
 
 use rustc_data_structures::intern::Interned;
+use rustc_errors::{DiagnosticArgValue, IntoDiagnosticArg};
 use rustc_hir::def_id::DefId;
 use rustc_macros::HashStable;
 use rustc_serialize::{self, Decodable, Encodable};
@@ -36,6 +37,12 @@ pub struct GenericArg<'tcx> {
     marker: PhantomData<(Ty<'tcx>, ty::Region<'tcx>, ty::Const<'tcx>)>,
 }
 
+impl<'tcx> IntoDiagnosticArg for GenericArg<'tcx> {
+    fn into_diagnostic_arg(self) -> DiagnosticArgValue<'static> {
+        self.to_string().into_diagnostic_arg()
+    }
+}
+
 const TAG_MASK: usize = 0b11;
 const TYPE_TAG: usize = 0b00;
 const REGION_TAG: usize = 0b01;
@@ -538,6 +545,9 @@ impl<'tcx, T: TypeVisitable<'tcx>> TypeVisitable<'tcx> for &'tcx ty::List<T> {
 /// Similar to [`super::Binder`] except that it tracks early bound generics, i.e. `struct Foo<T>(T)`
 /// needs `T` substituted immediately. This type primarily exists to avoid forgetting to call
 /// `subst`.
+///
+/// If you don't have anything to `subst`, you may be looking for
+/// [`subst_identity`](EarlyBinder::subst_identity) or [`skip_binder`](EarlyBinder::skip_binder).
 #[derive(Copy, Clone, PartialEq, Eq, PartialOrd, Ord, Hash, Debug)]
 #[derive(Encodable, Decodable, HashStable)]
 pub struct EarlyBinder<T>(pub T);
@@ -578,6 +588,14 @@ impl<T> EarlyBinder<T> {
         EarlyBinder(value)
     }
 
+    /// Skips the binder and returns the "bound" value.
+    /// This can be used to extract data that does not depend on generic parameters
+    /// (e.g., getting the `DefId` of the inner value or getting the number of
+    /// arguments of an `FnSig`). Otherwise, consider using
+    /// [`subst_identity`](EarlyBinder::subst_identity).
+    ///
+    /// See also [`Binder::skip_binder`](super::Binder::skip_binder), which is
+    /// the analogous operation on [`super::Binder`].
     pub fn skip_binder(self) -> T {
         self.0
     }
@@ -639,6 +657,13 @@ where
     }
 }
 
+impl<'tcx, I: IntoIterator> ExactSizeIterator for SubstIter<'_, 'tcx, I>
+where
+    I::IntoIter: ExactSizeIterator,
+    I::Item: TypeFoldable<'tcx>,
+{
+}
+
 impl<'tcx, 's, I: IntoIterator> EarlyBinder<I>
 where
     I::Item: Deref,
@@ -686,6 +711,14 @@ where
     }
 }
 
+impl<'tcx, I: IntoIterator> ExactSizeIterator for SubstIterCopied<'_, 'tcx, I>
+where
+    I::IntoIter: ExactSizeIterator,
+    I::Item: Deref,
+    <I::Item as Deref>::Target: Copy + TypeFoldable<'tcx>,
+{
+}
+
 pub struct EarlyBinderIter<T> {
     t: T,
 }
@@ -714,6 +747,14 @@ impl<'tcx, T: TypeFoldable<'tcx>> ty::EarlyBinder<T> {
         self.0.fold_with(&mut folder)
     }
 
+    /// Makes the identity substitution `T0 => T0, ..., TN => TN`.
+    /// Conceptually, this converts universally bound variables into placeholders
+    /// when inside of a given item.
+    ///
+    /// For example, consider `for<T> fn foo<T>(){ .. }`:
+    /// - Outside of `foo`, `T` is bound (represented by the presence of `EarlyBinder`).
+    /// - Inside of the body of `foo`, we treat `T` as a placeholder by calling
+    /// `subst_identity` to discharge the `EarlyBinder`.
     pub fn subst_identity(self) -> T {
         self.0
     }
diff --git a/compiler/rustc_middle/src/ty/typeck_results.rs b/compiler/rustc_middle/src/ty/typeck_results.rs
index 18281b5175c..2902c6dc556 100644
--- a/compiler/rustc_middle/src/ty/typeck_results.rs
+++ b/compiler/rustc_middle/src/ty/typeck_results.rs
@@ -6,7 +6,12 @@ use crate::{
         GenericArgKind, InternalSubsts, SubstsRef, Ty, UserSubsts,
     },
 };
-use rustc_data_structures::{fx::FxHashMap, sync::Lrc, unord::UnordSet, vec_map::VecMap};
+use rustc_data_structures::{
+    fx::FxHashMap,
+    sync::Lrc,
+    unord::{UnordItems, UnordSet},
+    vec_map::VecMap,
+};
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir as hir;
 use rustc_hir::{
@@ -20,11 +25,7 @@ use rustc_macros::HashStable;
 use rustc_middle::mir::FakeReadCause;
 use rustc_session::Session;
 use rustc_span::Span;
-use std::{
-    collections::hash_map::{self, Entry},
-    hash::Hash,
-    iter,
-};
+use std::{collections::hash_map::Entry, hash::Hash, iter};
 
 use super::RvalueScopes;
 
@@ -567,8 +568,15 @@ impl<'a, V> LocalTableInContext<'a, V> {
         self.data.get(&id.local_id)
     }
 
-    pub fn iter(&self) -> hash_map::Iter<'_, hir::ItemLocalId, V> {
-        self.data.iter()
+    pub fn items(
+        &'a self,
+    ) -> UnordItems<(hir::ItemLocalId, &'a V), impl Iterator<Item = (hir::ItemLocalId, &'a V)>>
+    {
+        self.data.items().map(|(id, value)| (*id, value))
+    }
+
+    pub fn items_in_stable_order(&self) -> Vec<(ItemLocalId, &'a V)> {
+        self.data.to_sorted_stable_ord()
     }
 }
 
@@ -605,6 +613,16 @@ impl<'a, V> LocalTableInContextMut<'a, V> {
         validate_hir_id_for_typeck_results(self.hir_owner, id);
         self.data.remove(&id.local_id)
     }
+
+    pub fn extend(
+        &mut self,
+        items: UnordItems<(hir::HirId, V), impl Iterator<Item = (hir::HirId, V)>>,
+    ) {
+        self.data.extend(items.map(|(id, value)| {
+            validate_hir_id_for_typeck_results(self.hir_owner, id);
+            (id.local_id, value)
+        }))
+    }
 }
 
 rustc_index::newtype_index! {
diff --git a/compiler/rustc_middle/src/ty/util.rs b/compiler/rustc_middle/src/ty/util.rs
index 1286a5253c0..d0d1dcc584f 100644
--- a/compiler/rustc_middle/src/ty/util.rs
+++ b/compiler/rustc_middle/src/ty/util.rs
@@ -659,27 +659,6 @@ impl<'tcx> TyCtxt<'tcx> {
         ty::EarlyBinder(self.explicit_item_bounds(def_id))
     }
 
-    pub fn bound_item_bounds(
-        self,
-        def_id: DefId,
-    ) -> ty::EarlyBinder<&'tcx ty::List<ty::Predicate<'tcx>>> {
-        ty::EarlyBinder(self.item_bounds(def_id))
-    }
-
-    pub fn bound_predicates_of(
-        self,
-        def_id: DefId,
-    ) -> ty::EarlyBinder<ty::generics::GenericPredicates<'tcx>> {
-        ty::EarlyBinder(self.predicates_of(def_id))
-    }
-
-    pub fn bound_explicit_predicates_of(
-        self,
-        def_id: DefId,
-    ) -> ty::EarlyBinder<ty::generics::GenericPredicates<'tcx>> {
-        ty::EarlyBinder(self.explicit_predicates_of(def_id))
-    }
-
     pub fn bound_impl_subject(self, def_id: DefId) -> ty::EarlyBinder<ty::ImplSubject<'tcx>> {
         ty::EarlyBinder(self.impl_subject(def_id))
     }
diff --git a/compiler/rustc_middle/src/ty/visit.rs b/compiler/rustc_middle/src/ty/visit.rs
index ca445558131..bee3cc4d7cb 100644
--- a/compiler/rustc_middle/src/ty/visit.rs
+++ b/compiler/rustc_middle/src/ty/visit.rs
@@ -294,13 +294,13 @@ impl<'tcx> TyCtxt<'tcx> {
             fn visit_region(&mut self, r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
                 match *r {
                     ty::ReLateBound(debruijn, _) if debruijn < self.outer_index => {
-                        ControlFlow::CONTINUE
+                        ControlFlow::Continue(())
                     }
                     _ => {
                         if (self.callback)(r) {
-                            ControlFlow::BREAK
+                            ControlFlow::Break(())
                         } else {
-                            ControlFlow::CONTINUE
+                            ControlFlow::Continue(())
                         }
                     }
                 }
@@ -311,7 +311,7 @@ impl<'tcx> TyCtxt<'tcx> {
                 if ty.flags().intersects(TypeFlags::HAS_FREE_REGIONS) {
                     ty.super_visit_with(self)
                 } else {
-                    ControlFlow::CONTINUE
+                    ControlFlow::Continue(())
                 }
             }
         }
@@ -394,7 +394,7 @@ impl<'tcx> TypeVisitor<'tcx> for ValidateBoundVars<'tcx> {
         if t.outer_exclusive_binder() < self.binder_index
             || !self.visited.insert((self.binder_index, t))
         {
-            return ControlFlow::BREAK;
+            return ControlFlow::Break(());
         }
         match *t.kind() {
             ty::Bound(debruijn, bound_ty) if debruijn == self.binder_index => {
@@ -512,7 +512,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasEscapingVarsVisitor {
         if t.outer_exclusive_binder() > self.outer_index {
             ControlFlow::Break(FoundEscapingVars)
         } else {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         }
     }
 
@@ -524,7 +524,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasEscapingVarsVisitor {
         if r.bound_at_or_above_binder(self.outer_index) {
             ControlFlow::Break(FoundEscapingVars)
         } else {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         }
     }
 
@@ -547,7 +547,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasEscapingVarsVisitor {
         if predicate.outer_exclusive_binder() > self.outer_index {
             ControlFlow::Break(FoundEscapingVars)
         } else {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         }
     }
 }
@@ -575,7 +575,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
         if flags.intersects(self.flags) {
             ControlFlow::Break(FoundFlags)
         } else {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         }
     }
 
@@ -585,7 +585,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
         if flags.intersects(self.flags) {
             ControlFlow::Break(FoundFlags)
         } else {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         }
     }
 
@@ -596,7 +596,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
         if flags.intersects(self.flags) {
             ControlFlow::Break(FoundFlags)
         } else {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         }
     }
 
@@ -605,7 +605,7 @@ impl<'tcx> TypeVisitor<'tcx> for HasTypeFlagsVisitor {
         if predicate.flags().intersects(self.flags) {
             ControlFlow::Break(FoundFlags)
         } else {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         }
     }
 }
@@ -653,7 +653,7 @@ impl<'tcx> TypeVisitor<'tcx> for LateBoundRegionsCollector {
         // in the normalized form
         if self.just_constrained {
             if let ty::Alias(..) = t.kind() {
-                return ControlFlow::CONTINUE;
+                return ControlFlow::Continue(());
             }
         }
 
@@ -666,7 +666,7 @@ impl<'tcx> TypeVisitor<'tcx> for LateBoundRegionsCollector {
         // in the normalized form
         if self.just_constrained {
             if let ty::ConstKind::Unevaluated(..) = c.kind() {
-                return ControlFlow::CONTINUE;
+                return ControlFlow::Continue(());
             }
         }
 
@@ -679,7 +679,7 @@ impl<'tcx> TypeVisitor<'tcx> for LateBoundRegionsCollector {
                 self.regions.insert(br.kind);
             }
         }
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
 
@@ -726,6 +726,6 @@ impl<'tcx> TypeVisitor<'tcx> for MaxUniverse {
             );
         }
 
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
diff --git a/compiler/rustc_mir_build/src/build/custom/mod.rs b/compiler/rustc_mir_build/src/build/custom/mod.rs
index 34fefb99e09..33fdc1901cd 100644
--- a/compiler/rustc_mir_build/src/build/custom/mod.rs
+++ b/compiler/rustc_mir_build/src/build/custom/mod.rs
@@ -86,10 +86,10 @@ pub(super) fn build_custom_mir<'tcx>(
         block_map: FxHashMap::default(),
     };
 
-    let res = (|| {
+    let res: PResult<_> = try {
         pctxt.parse_args(&params)?;
-        pctxt.parse_body(expr)
-    })();
+        pctxt.parse_body(expr)?;
+    };
     if let Err(err) = res {
         tcx.sess.diagnostic().span_fatal(
             err.span,
diff --git a/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs b/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs
index dca4906c07d..0bca02589bc 100644
--- a/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs
+++ b/compiler/rustc_mir_build/src/build/custom/parse/instruction.rs
@@ -12,6 +12,12 @@ use super::{parse_by_kind, PResult, ParseCtxt};
 impl<'tcx, 'body> ParseCtxt<'tcx, 'body> {
     pub fn parse_statement(&self, expr_id: ExprId) -> PResult<StatementKind<'tcx>> {
         parse_by_kind!(self, expr_id, _, "statement",
+            @call("mir_storage_live", args) => {
+                Ok(StatementKind::StorageLive(self.parse_local(args[0])?))
+            },
+            @call("mir_storage_dead", args) => {
+                Ok(StatementKind::StorageDead(self.parse_local(args[0])?))
+            },
             @call("mir_retag", args) => {
                 Ok(StatementKind::Retag(RetagKind::Default, Box::new(self.parse_place(args[0])?)))
             },
diff --git a/compiler/rustc_mir_build/src/build/expr/stmt.rs b/compiler/rustc_mir_build/src/build/expr/stmt.rs
index a73ab344718..78083685193 100644
--- a/compiler/rustc_mir_build/src/build/expr/stmt.rs
+++ b/compiler/rustc_mir_build/src/build/expr/stmt.rs
@@ -113,7 +113,7 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                 //
                 // it is usually better to focus on `the_value` rather
                 // than the entirety of block(s) surrounding it.
-                let adjusted_span = (|| {
+                let adjusted_span =
                     if let ExprKind::Block { block } = expr.kind
                         && let Some(tail_ex) = this.thir[block].expr
                     {
@@ -135,10 +135,10 @@ impl<'a, 'tcx> Builder<'a, 'tcx> {
                             tail_result_is_ignored: true,
                             span: expr.span,
                         });
-                        return Some(expr.span);
-                    }
-                    None
-                })();
+                        Some(expr.span)
+                    } else {
+                        None
+                    };
 
                 let temp =
                     unpack!(block = this.as_temp(block, statement_scope, expr, Mutability::Not));
diff --git a/compiler/rustc_mir_build/src/errors.rs b/compiler/rustc_mir_build/src/errors.rs
index 06523b0a1de..7f81aef1c73 100644
--- a/compiler/rustc_mir_build/src/errors.rs
+++ b/compiler/rustc_mir_build/src/errors.rs
@@ -770,6 +770,8 @@ pub(crate) struct PatternNotCovered<'s, 'tcx> {
     #[subdiagnostic]
     pub let_suggestion: Option<SuggestLet>,
     #[subdiagnostic]
+    pub misc_suggestion: Option<MiscPatternSuggestion>,
+    #[subdiagnostic]
     pub res_defined_here: Option<ResDefinedHere>,
 }
 
@@ -848,3 +850,16 @@ pub enum SuggestLet {
         count: usize,
     },
 }
+
+#[derive(Subdiagnostic)]
+pub enum MiscPatternSuggestion {
+    #[suggestion(
+        mir_build_suggest_attempted_int_lit,
+        code = "_",
+        applicability = "maybe-incorrect"
+    )]
+    AttemptedIntegerLiteral {
+        #[primary_span]
+        start_span: Span,
+    },
+}
diff --git a/compiler/rustc_mir_build/src/lib.rs b/compiler/rustc_mir_build/src/lib.rs
index fb7ae6f1d24..a428180a4fa 100644
--- a/compiler/rustc_mir_build/src/lib.rs
+++ b/compiler/rustc_mir_build/src/lib.rs
@@ -5,7 +5,6 @@
 #![feature(assert_matches)]
 #![feature(associated_type_bounds)]
 #![feature(box_patterns)]
-#![feature(control_flow_enum)]
 #![feature(if_let_guard)]
 #![feature(let_chains)]
 #![feature(min_specialization)]
diff --git a/compiler/rustc_mir_build/src/lints.rs b/compiler/rustc_mir_build/src/lints.rs
index fac4997fcbf..f67f24b43c4 100644
--- a/compiler/rustc_mir_build/src/lints.rs
+++ b/compiler/rustc_mir_build/src/lints.rs
@@ -118,7 +118,7 @@ impl<'mir, 'tcx> TriColorVisitor<BasicBlocks<'tcx>> for Search<'mir, 'tcx> {
             // A diverging InlineAsm is treated as non-recursing
             TerminatorKind::InlineAsm { destination, .. } => {
                 if destination.is_some() {
-                    ControlFlow::CONTINUE
+                    ControlFlow::Continue(())
                 } else {
                     ControlFlow::Break(NonRecursive)
                 }
@@ -132,7 +132,7 @@ impl<'mir, 'tcx> TriColorVisitor<BasicBlocks<'tcx>> for Search<'mir, 'tcx> {
             | TerminatorKind::FalseEdge { .. }
             | TerminatorKind::FalseUnwind { .. }
             | TerminatorKind::Goto { .. }
-            | TerminatorKind::SwitchInt { .. } => ControlFlow::CONTINUE,
+            | TerminatorKind::SwitchInt { .. } => ControlFlow::Continue(()),
         }
     }
 
@@ -145,7 +145,7 @@ impl<'mir, 'tcx> TriColorVisitor<BasicBlocks<'tcx>> for Search<'mir, 'tcx> {
             }
         }
 
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 
     fn ignore_edge(&mut self, bb: BasicBlock, target: BasicBlock) -> bool {
diff --git a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
index e13c0662ef8..34e637f5948 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/check_match.rs
@@ -6,8 +6,9 @@ use super::{PatCtxt, PatternError};
 
 use crate::errors::*;
 
+use hir::{ExprKind, PatKind};
 use rustc_arena::TypedArena;
-use rustc_ast::Mutability;
+use rustc_ast::{LitKind, Mutability};
 use rustc_errors::{
     struct_span_err, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan,
 };
@@ -389,7 +390,7 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
             return;
         }
 
-        let (inform, interpreted_as_const, res_defined_here,let_suggestion) =
+        let (inform, interpreted_as_const, res_defined_here,let_suggestion, misc_suggestion) =
             if let hir::PatKind::Path(hir::QPath::Resolved(
                 None,
                 hir::Path {
@@ -413,6 +414,7 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
                         }
                     },
                     None,
+                    None,
                 )
             } else if let Some(span) = sp && self.tcx.sess.source_map().is_span_accessible(span) {
                 let mut bindings = vec![];
@@ -426,10 +428,19 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
                 let end_span = semi_span.shrink_to_lo();
                 let count = witnesses.len();
 
+                // If the pattern to match is an integer literal:
+                let int_suggestion = if
+                    let PatKind::Lit(expr) = &pat.kind
+                    && bindings.is_empty()
+                    && let ExprKind::Lit(Spanned { node: LitKind::Int(_, _), span }) = expr.kind {
+                    // Then give a suggestion, the user might've meant to create a binding instead.
+                    Some(MiscPatternSuggestion::AttemptedIntegerLiteral { start_span: span.shrink_to_lo() })
+                } else { None };
+
                 let let_suggestion = if bindings.is_empty() {SuggestLet::If{start_span, semi_span, count}} else{ SuggestLet::Else{end_span, count }};
-                (sp.map(|_|Inform), None, None, Some(let_suggestion))
+                (sp.map(|_|Inform), None, None, Some(let_suggestion), int_suggestion)
             } else{
-                (sp.map(|_|Inform), None, None,  None)
+                (sp.map(|_|Inform), None, None,  None, None)
             };
 
         let adt_defined_here = try {
@@ -453,6 +464,7 @@ impl<'p, 'tcx> MatchVisitor<'_, 'p, 'tcx> {
             _p: (),
             pattern_ty,
             let_suggestion,
+            misc_suggestion,
             res_defined_here,
             adt_defined_here,
         });
diff --git a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
index 17b3c475f83..aba5429da43 100644
--- a/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
+++ b/compiler/rustc_mir_build/src/thir/pattern/deconstruct_pat.rs
@@ -141,27 +141,22 @@ impl IntRange {
     ) -> Option<IntRange> {
         let ty = value.ty();
         if let Some((target_size, bias)) = Self::integral_size_and_signed_bias(tcx, ty) {
-            let val = (|| {
-                match value {
-                    mir::ConstantKind::Val(ConstValue::Scalar(scalar), _) => {
-                        // For this specific pattern we can skip a lot of effort and go
-                        // straight to the result, after doing a bit of checking. (We
-                        // could remove this branch and just fall through, which
-                        // is more general but much slower.)
-                        return scalar.to_bits_or_ptr_internal(target_size).unwrap().left();
-                    }
-                    mir::ConstantKind::Ty(c) => match c.kind() {
-                        ty::ConstKind::Value(_) => bug!(
-                            "encountered ConstValue in mir::ConstantKind::Ty, whereas this is expected to be in ConstantKind::Val"
-                        ),
-                        _ => {}
-                    },
-                    _ => {}
+            let val = if let mir::ConstantKind::Val(ConstValue::Scalar(scalar), _) = value {
+                // For this specific pattern we can skip a lot of effort and go
+                // straight to the result, after doing a bit of checking. (We
+                // could remove this branch and just fall through, which
+                // is more general but much slower.)
+                scalar.to_bits_or_ptr_internal(target_size).unwrap().left()?
+            } else {
+                if let mir::ConstantKind::Ty(c) = value
+                    && let ty::ConstKind::Value(_) = c.kind()
+                {
+                    bug!("encountered ConstValue in mir::ConstantKind::Ty, whereas this is expected to be in ConstantKind::Val");
                 }
 
                 // This is a more general form of the previous case.
-                value.try_eval_bits(tcx, param_env, ty)
-            })()?;
+                value.try_eval_bits(tcx, param_env, ty)?
+            };
             let val = val ^ bias;
             Some(IntRange { range: val..=val, bias })
         } else {
diff --git a/compiler/rustc_mir_transform/src/coverage/spans.rs b/compiler/rustc_mir_transform/src/coverage/spans.rs
index 9f842c929dc..c5434840453 100644
--- a/compiler/rustc_mir_transform/src/coverage/spans.rs
+++ b/compiler/rustc_mir_transform/src/coverage/spans.rs
@@ -341,11 +341,11 @@ impl<'a, 'tcx> CoverageSpans<'a, 'tcx> {
                     if a.is_in_same_bcb(b) {
                         Some(Ordering::Equal)
                     } else {
-                        // Sort equal spans by dominator relationship, in reverse order (so
-                        // dominators always come after the dominated equal spans). When later
-                        // comparing two spans in order, the first will either dominate the second,
-                        // or they will have no dominator relationship.
-                        self.basic_coverage_blocks.dominators().rank_partial_cmp(b.bcb, a.bcb)
+                        // Sort equal spans by dominator relationship (so dominators always come
+                        // before the dominated equal spans). When later comparing two spans in
+                        // order, the first will either dominate the second, or they will have no
+                        // dominator relationship.
+                        self.basic_coverage_blocks.dominators().rank_partial_cmp(a.bcb, b.bcb)
                     }
                 } else {
                     // Sort hi() in reverse order so shorter spans are attempted after longer spans.
diff --git a/compiler/rustc_mir_transform/src/generator.rs b/compiler/rustc_mir_transform/src/generator.rs
index c097af61611..39c61a34afc 100644
--- a/compiler/rustc_mir_transform/src/generator.rs
+++ b/compiler/rustc_mir_transform/src/generator.rs
@@ -460,6 +460,104 @@ fn replace_local<'tcx>(
     new_local
 }
 
+/// Transforms the `body` of the generator applying the following transforms:
+///
+/// - Eliminates all the `get_context` calls that async lowering created.
+/// - Replace all `Local` `ResumeTy` types with `&mut Context<'_>` (`context_mut_ref`).
+///
+/// The `Local`s that have their types replaced are:
+/// - The `resume` argument itself.
+/// - The argument to `get_context`.
+/// - The yielded value of a `yield`.
+///
+/// The `ResumeTy` hides a `&mut Context<'_>` behind an unsafe raw pointer, and the
+/// `get_context` function is being used to convert that back to a `&mut Context<'_>`.
+///
+/// Ideally the async lowering would not use the `ResumeTy`/`get_context` indirection,
+/// but rather directly use `&mut Context<'_>`, however that would currently
+/// lead to higher-kinded lifetime errors.
+/// See <https://github.com/rust-lang/rust/issues/105501>.
+///
+/// The async lowering step and the type / lifetime inference / checking are
+/// still using the `ResumeTy` indirection for the time being, and that indirection
+/// is removed here. After this transform, the generator body only knows about `&mut Context<'_>`.
+fn transform_async_context<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
+    let context_mut_ref = tcx.mk_task_context();
+
+    // replace the type of the `resume` argument
+    replace_resume_ty_local(tcx, body, Local::new(2), context_mut_ref);
+
+    let get_context_def_id = tcx.require_lang_item(LangItem::GetContext, None);
+
+    for bb in BasicBlock::new(0)..body.basic_blocks.next_index() {
+        let bb_data = &body[bb];
+        if bb_data.is_cleanup {
+            continue;
+        }
+
+        match &bb_data.terminator().kind {
+            TerminatorKind::Call { func, .. } => {
+                let func_ty = func.ty(body, tcx);
+                if let ty::FnDef(def_id, _) = *func_ty.kind() {
+                    if def_id == get_context_def_id {
+                        let local = eliminate_get_context_call(&mut body[bb]);
+                        replace_resume_ty_local(tcx, body, local, context_mut_ref);
+                    }
+                } else {
+                    continue;
+                }
+            }
+            TerminatorKind::Yield { resume_arg, .. } => {
+                replace_resume_ty_local(tcx, body, resume_arg.local, context_mut_ref);
+            }
+            _ => {}
+        }
+    }
+}
+
+fn eliminate_get_context_call<'tcx>(bb_data: &mut BasicBlockData<'tcx>) -> Local {
+    let terminator = bb_data.terminator.take().unwrap();
+    if let TerminatorKind::Call { mut args, destination, target, .. } = terminator.kind {
+        let arg = args.pop().unwrap();
+        let local = arg.place().unwrap().local;
+
+        let arg = Rvalue::Use(arg);
+        let assign = Statement {
+            source_info: terminator.source_info,
+            kind: StatementKind::Assign(Box::new((destination, arg))),
+        };
+        bb_data.statements.push(assign);
+        bb_data.terminator = Some(Terminator {
+            source_info: terminator.source_info,
+            kind: TerminatorKind::Goto { target: target.unwrap() },
+        });
+        local
+    } else {
+        bug!();
+    }
+}
+
+#[cfg_attr(not(debug_assertions), allow(unused))]
+fn replace_resume_ty_local<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    body: &mut Body<'tcx>,
+    local: Local,
+    context_mut_ref: Ty<'tcx>,
+) {
+    let local_ty = std::mem::replace(&mut body.local_decls[local].ty, context_mut_ref);
+    // We have to replace the `ResumeTy` that is used for type and borrow checking
+    // with `&mut Context<'_>` in MIR.
+    #[cfg(debug_assertions)]
+    {
+        if let ty::Adt(resume_ty_adt, _) = local_ty.kind() {
+            let expected_adt = tcx.adt_def(tcx.require_lang_item(LangItem::ResumeTy, None));
+            assert_eq!(*resume_ty_adt, expected_adt);
+        } else {
+            panic!("expected `ResumeTy`, found `{:?}`", local_ty);
+        };
+    }
+}
+
 struct LivenessInfo {
     /// Which locals are live across any suspension point.
     saved_locals: GeneratorSavedLocals,
@@ -1283,13 +1381,13 @@ impl<'tcx> MirPass<'tcx> for StateTransform {
             }
         };
 
-        let is_async_kind = body.generator_kind().unwrap() != GeneratorKind::Gen;
+        let is_async_kind = matches!(body.generator_kind(), Some(GeneratorKind::Async(_)));
         let (state_adt_ref, state_substs) = if is_async_kind {
             // Compute Poll<return_ty>
-            let state_did = tcx.require_lang_item(LangItem::Poll, None);
-            let state_adt_ref = tcx.adt_def(state_did);
-            let state_substs = tcx.intern_substs(&[body.return_ty().into()]);
-            (state_adt_ref, state_substs)
+            let poll_did = tcx.require_lang_item(LangItem::Poll, None);
+            let poll_adt_ref = tcx.adt_def(poll_did);
+            let poll_substs = tcx.intern_substs(&[body.return_ty().into()]);
+            (poll_adt_ref, poll_substs)
         } else {
             // Compute GeneratorState<yield_ty, return_ty>
             let state_did = tcx.require_lang_item(LangItem::GeneratorState, None);
@@ -1303,13 +1401,19 @@ impl<'tcx> MirPass<'tcx> for StateTransform {
         // RETURN_PLACE then is a fresh unused local with type ret_ty.
         let new_ret_local = replace_local(RETURN_PLACE, ret_ty, body, tcx);
 
+        // Replace all occurrences of `ResumeTy` with `&mut Context<'_>` within async bodies.
+        if is_async_kind {
+            transform_async_context(tcx, body);
+        }
+
         // We also replace the resume argument and insert an `Assign`.
         // This is needed because the resume argument `_2` might be live across a `yield`, in which
         // case there is no `Assign` to it that the transform can turn into a store to the generator
         // state. After the yield the slot in the generator state would then be uninitialized.
         let resume_local = Local::new(2);
-        let new_resume_local =
-            replace_local(resume_local, body.local_decls[resume_local].ty, body, tcx);
+        let resume_ty =
+            if is_async_kind { tcx.mk_task_context() } else { body.local_decls[resume_local].ty };
+        let new_resume_local = replace_local(resume_local, resume_ty, body, tcx);
 
         // When first entering the generator, move the resume argument into its new local.
         let source_info = SourceInfo::outermost(body.span);
diff --git a/compiler/rustc_mir_transform/src/inline.rs b/compiler/rustc_mir_transform/src/inline.rs
index 4219e6280eb..28c9080d38d 100644
--- a/compiler/rustc_mir_transform/src/inline.rs
+++ b/compiler/rustc_mir_transform/src/inline.rs
@@ -542,6 +542,21 @@ impl<'tcx> Inliner<'tcx> {
                     destination
                 };
 
+                // Always create a local to hold the destination, as `RETURN_PLACE` may appear
+                // where a full `Place` is not allowed.
+                let (remap_destination, destination_local) = if let Some(d) = dest.as_local() {
+                    (false, d)
+                } else {
+                    (
+                        true,
+                        self.new_call_temp(
+                            caller_body,
+                            &callsite,
+                            destination.ty(caller_body, self.tcx).ty,
+                        ),
+                    )
+                };
+
                 // Copy the arguments if needed.
                 let args: Vec<_> = self.make_call_args(args, &callsite, caller_body, &callee_body);
 
@@ -560,7 +575,7 @@ impl<'tcx> Inliner<'tcx> {
                     new_locals: Local::new(caller_body.local_decls.len())..,
                     new_scopes: SourceScope::new(caller_body.source_scopes.len())..,
                     new_blocks: BasicBlock::new(caller_body.basic_blocks.len())..,
-                    destination: dest,
+                    destination: destination_local,
                     callsite_scope: caller_body.source_scopes[callsite.source_info.scope].clone(),
                     callsite,
                     cleanup_block: cleanup,
@@ -591,6 +606,16 @@ impl<'tcx> Inliner<'tcx> {
                     // To avoid repeated O(n) insert, push any new statements to the end and rotate
                     // the slice once.
                     let mut n = 0;
+                    if remap_destination {
+                        caller_body[block].statements.push(Statement {
+                            source_info: callsite.source_info,
+                            kind: StatementKind::Assign(Box::new((
+                                dest,
+                                Rvalue::Use(Operand::Move(destination_local.into())),
+                            ))),
+                        });
+                        n += 1;
+                    }
                     for local in callee_body.vars_and_temps_iter().rev() {
                         if !callee_body.local_decls[local].internal
                             && integrator.always_live_locals.contains(local)
@@ -959,7 +984,7 @@ struct Integrator<'a, 'tcx> {
     new_locals: RangeFrom<Local>,
     new_scopes: RangeFrom<SourceScope>,
     new_blocks: RangeFrom<BasicBlock>,
-    destination: Place<'tcx>,
+    destination: Local,
     callsite_scope: SourceScopeData<'tcx>,
     callsite: &'a CallSite<'tcx>,
     cleanup_block: Option<BasicBlock>,
@@ -972,7 +997,7 @@ struct Integrator<'a, 'tcx> {
 impl Integrator<'_, '_> {
     fn map_local(&self, local: Local) -> Local {
         let new = if local == RETURN_PLACE {
-            self.destination.local
+            self.destination
         } else {
             let idx = local.index() - 1;
             if idx < self.args.len() {
@@ -1053,27 +1078,6 @@ impl<'tcx> MutVisitor<'tcx> for Integrator<'_, 'tcx> {
         *span = span.fresh_expansion(self.expn_data);
     }
 
-    fn visit_place(&mut self, place: &mut Place<'tcx>, context: PlaceContext, location: Location) {
-        for elem in place.projection {
-            // FIXME: Make sure that return place is not used in an indexing projection, since it
-            // won't be rebased as it is supposed to be.
-            assert_ne!(ProjectionElem::Index(RETURN_PLACE), elem);
-        }
-
-        // If this is the `RETURN_PLACE`, we need to rebase any projections onto it.
-        let dest_proj_len = self.destination.projection.len();
-        if place.local == RETURN_PLACE && dest_proj_len > 0 {
-            let mut projs = Vec::with_capacity(dest_proj_len + place.projection.len());
-            projs.extend(self.destination.projection);
-            projs.extend(place.projection);
-
-            place.projection = self.tcx.intern_place_elems(&*projs);
-        }
-        // Handles integrating any locals that occur in the base
-        // or projections
-        self.super_place(place, context, location)
-    }
-
     fn visit_basic_block_data(&mut self, block: BasicBlock, data: &mut BasicBlockData<'tcx>) {
         self.in_cleanup_block = data.is_cleanup;
         self.super_basic_block_data(block, data);
diff --git a/compiler/rustc_mir_transform/src/lib.rs b/compiler/rustc_mir_transform/src/lib.rs
index 16b8a901f36..20b7fdcfe6d 100644
--- a/compiler/rustc_mir_transform/src/lib.rs
+++ b/compiler/rustc_mir_transform/src/lib.rs
@@ -487,7 +487,6 @@ fn run_analysis_to_runtime_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>
 fn run_analysis_cleanup_passes<'tcx>(tcx: TyCtxt<'tcx>, body: &mut Body<'tcx>) {
     let passes: &[&dyn MirPass<'tcx>] = &[
         &cleanup_post_borrowck::CleanupPostBorrowck,
-        &simplify_branches::SimplifyConstCondition::new("initial"),
         &remove_noop_landing_pads::RemoveNoopLandingPads,
         &simplify::SimplifyCfg::new("early-opt"),
         &deref_separator::Derefer,
diff --git a/compiler/rustc_monomorphize/src/lib.rs b/compiler/rustc_monomorphize/src/lib.rs
index b616ed35d99..f88155e4fc7 100644
--- a/compiler/rustc_monomorphize/src/lib.rs
+++ b/compiler/rustc_monomorphize/src/lib.rs
@@ -1,5 +1,4 @@
 #![feature(array_windows)]
-#![feature(control_flow_enum)]
 #![recursion_limit = "256"]
 #![allow(rustc::potential_query_instability)]
 #![deny(rustc::untranslatable_diagnostic)]
diff --git a/compiler/rustc_monomorphize/src/polymorphize.rs b/compiler/rustc_monomorphize/src/polymorphize.rs
index c8fc69eb856..cf13d4584a1 100644
--- a/compiler/rustc_monomorphize/src/polymorphize.rs
+++ b/compiler/rustc_monomorphize/src/polymorphize.rs
@@ -300,20 +300,20 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
     #[instrument(level = "debug", skip(self))]
     fn visit_const(&mut self, c: Const<'tcx>) -> ControlFlow<Self::BreakTy> {
         if !c.has_non_region_param() {
-            return ControlFlow::CONTINUE;
+            return ControlFlow::Continue(());
         }
 
         match c.kind() {
             ty::ConstKind::Param(param) => {
                 debug!(?param);
                 self.unused_parameters.mark_used(param.index);
-                ControlFlow::CONTINUE
+                ControlFlow::Continue(())
             }
             ty::ConstKind::Unevaluated(ty::UnevaluatedConst { def, substs })
                 if matches!(self.tcx.def_kind(def.did), DefKind::AnonConst) =>
             {
                 self.visit_child_body(def.did, substs);
-                ControlFlow::CONTINUE
+                ControlFlow::Continue(())
             }
             _ => c.super_visit_with(self),
         }
@@ -322,7 +322,7 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
     #[instrument(level = "debug", skip(self))]
     fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
         if !ty.has_non_region_param() {
-            return ControlFlow::CONTINUE;
+            return ControlFlow::Continue(());
         }
 
         match *ty.kind() {
@@ -330,18 +330,18 @@ impl<'a, 'tcx> TypeVisitor<'tcx> for MarkUsedGenericParams<'a, 'tcx> {
                 debug!(?def_id);
                 // Avoid cycle errors with generators.
                 if def_id == self.def_id {
-                    return ControlFlow::CONTINUE;
+                    return ControlFlow::Continue(());
                 }
 
                 // Consider any generic parameters used by any closures/generators as used in the
                 // parent.
                 self.visit_child_body(def_id, substs);
-                ControlFlow::CONTINUE
+                ControlFlow::Continue(())
             }
             ty::Param(param) => {
                 debug!(?param);
                 self.unused_parameters.mark_used(param.index);
-                ControlFlow::CONTINUE
+                ControlFlow::Continue(())
             }
             _ => ty.super_visit_with(self),
         }
diff --git a/compiler/rustc_parse/src/lexer/mod.rs b/compiler/rustc_parse/src/lexer/mod.rs
index 8761c23625b..9fe8d9836ba 100644
--- a/compiler/rustc_parse/src/lexer/mod.rs
+++ b/compiler/rustc_parse/src/lexer/mod.rs
@@ -52,8 +52,15 @@ pub(crate) fn parse_token_trees<'a>(
     }
 
     let cursor = Cursor::new(src);
-    let string_reader =
-        StringReader { sess, start_pos, pos: start_pos, src, cursor, override_span };
+    let string_reader = StringReader {
+        sess,
+        start_pos,
+        pos: start_pos,
+        src,
+        cursor,
+        override_span,
+        nbsp_is_whitespace: false,
+    };
     tokentrees::TokenTreesReader::parse_all_token_trees(string_reader)
 }
 
@@ -68,6 +75,10 @@ struct StringReader<'a> {
     /// Cursor for getting lexer tokens.
     cursor: Cursor<'a>,
     override_span: Option<Span>,
+    /// When a "unknown start of token: \u{a0}" has already been emitted earlier
+    /// in this file, it's safe to treat further occurrences of the non-breaking
+    /// space character as whitespace.
+    nbsp_is_whitespace: bool,
 }
 
 impl<'a> StringReader<'a> {
@@ -239,6 +250,16 @@ impl<'a> StringReader<'a> {
                     }
                     let mut it = self.str_from_to_end(start).chars();
                     let c = it.next().unwrap();
+                    if c == '\u{00a0}' {
+                        // If an error has already been reported on non-breaking
+                        // space characters earlier in the file, treat all
+                        // subsequent occurrences as whitespace.
+                        if self.nbsp_is_whitespace {
+                            preceded_by_whitespace = true;
+                            continue;
+                        }
+                        self.nbsp_is_whitespace = true;
+                    }
                     let repeats = it.take_while(|c1| *c1 == c).count();
                     let mut err =
                         self.struct_err_span_char(start, self.pos + Pos::from_usize(repeats * c.len_utf8()), "unknown start of token", c);
@@ -486,7 +507,7 @@ impl<'a> StringReader<'a> {
 
     /// Slice of the source text from `start` up to but excluding `self.pos`,
     /// meaning the slice does not include the character `self.ch`.
-    fn str_from(&self, start: BytePos) -> &str {
+    fn str_from(&self, start: BytePos) -> &'a str {
         self.str_from_to(start, self.pos)
     }
 
@@ -497,12 +518,12 @@ impl<'a> StringReader<'a> {
     }
 
     /// Slice of the source text spanning from `start` up to but excluding `end`.
-    fn str_from_to(&self, start: BytePos, end: BytePos) -> &str {
+    fn str_from_to(&self, start: BytePos, end: BytePos) -> &'a str {
         &self.src[self.src_index(start)..self.src_index(end)]
     }
 
     /// Slice of the source text spanning from `start` until the end
-    fn str_from_to_end(&self, start: BytePos) -> &str {
+    fn str_from_to_end(&self, start: BytePos) -> &'a str {
         &self.src[self.src_index(start)..]
     }
 
diff --git a/compiler/rustc_parse/src/lexer/unicode_chars.rs b/compiler/rustc_parse/src/lexer/unicode_chars.rs
index 65479b341d7..34d003ccfa7 100644
--- a/compiler/rustc_parse/src/lexer/unicode_chars.rs
+++ b/compiler/rustc_parse/src/lexer/unicode_chars.rs
@@ -7,329 +7,331 @@ use rustc_errors::{Applicability, Diagnostic};
 use rustc_span::{symbol::kw, BytePos, Pos, Span};
 
 #[rustfmt::skip] // for line breaks
-pub(crate) const UNICODE_ARRAY: &[(char, &str, char)] = &[
-    ('
', "Line Separator", ' '),
-    ('
', "Paragraph Separator", ' '),
-    (' ', "Ogham Space mark", ' '),
-    (' ', "En Quad", ' '),
-    (' ', "Em Quad", ' '),
-    (' ', "En Space", ' '),
-    (' ', "Em Space", ' '),
-    (' ', "Three-Per-Em Space", ' '),
-    (' ', "Four-Per-Em Space", ' '),
-    (' ', "Six-Per-Em Space", ' '),
-    (' ', "Punctuation Space", ' '),
-    (' ', "Thin Space", ' '),
-    (' ', "Hair Space", ' '),
-    (' ', "Medium Mathematical Space", ' '),
-    (' ', "No-Break Space", ' '),
-    (' ', "Figure Space", ' '),
-    (' ', "Narrow No-Break Space", ' '),
-    ('　', "Ideographic Space", ' '),
-
-    ('ߺ', "Nko Lajanyalan", '_'),
-    ('﹍', "Dashed Low Line", '_'),
-    ('﹎', "Centreline Low Line", '_'),
-    ('﹏', "Wavy Low Line", '_'),
-    ('＿', "Fullwidth Low Line", '_'),
-
-    ('‐', "Hyphen", '-'),
-    ('‑', "Non-Breaking Hyphen", '-'),
-    ('‒', "Figure Dash", '-'),
-    ('–', "En Dash", '-'),
-    ('—', "Em Dash", '-'),
-    ('﹘', "Small Em Dash", '-'),
-    ('۔', "Arabic Full Stop", '-'),
-    ('⁃', "Hyphen Bullet", '-'),
-    ('˗', "Modifier Letter Minus Sign", '-'),
-    ('−', "Minus Sign", '-'),
-    ('➖', "Heavy Minus Sign", '-'),
-    ('Ⲻ', "Coptic Letter Dialect-P Ni", '-'),
-    ('ー', "Katakana-Hiragana Prolonged Sound Mark", '-'),
-    ('－', "Fullwidth Hyphen-Minus", '-'),
-    ('―', "Horizontal Bar", '-'),
-    ('─', "Box Drawings Light Horizontal", '-'),
-    ('━', "Box Drawings Heavy Horizontal", '-'),
-    ('㇐', "CJK Stroke H", '-'),
-    ('ꟷ', "Latin Epigraphic Letter Sideways I", '-'),
-    ('ᅳ', "Hangul Jungseong Eu", '-'),
-    ('ㅡ', "Hangul Letter Eu", '-'),
-    ('一', "CJK Unified Ideograph-4E00", '-'),
-    ('⼀', "Kangxi Radical One", '-'),
-
-    ('؍', "Arabic Date Separator", ','),
-    ('٫', "Arabic Decimal Separator", ','),
-    ('‚', "Single Low-9 Quotation Mark", ','),
-    ('¸', "Cedilla", ','),
-    ('ꓹ', "Lisu Letter Tone Na Po", ','),
-    ('，', "Fullwidth Comma", ','),
-
-    (';', "Greek Question Mark", ';'),
-    ('；', "Fullwidth Semicolon", ';'),
-    ('︔', "Presentation Form For Vertical Semicolon", ';'),
-
-    ('ः', "Devanagari Sign Visarga", ':'),
-    ('ઃ', "Gujarati Sign Visarga", ':'),
-    ('：', "Fullwidth Colon", ':'),
-    ('։', "Armenian Full Stop", ':'),
-    ('܃', "Syriac Supralinear Colon", ':'),
-    ('܄', "Syriac Sublinear Colon", ':'),
-    ('᛬', "Runic Multiple Punctuation", ':'),
-    ('︰', "Presentation Form For Vertical Two Dot Leader", ':'),
-    ('᠃', "Mongolian Full Stop", ':'),
-    ('᠉', "Mongolian Manchu Full Stop", ':'),
-    ('⁚', "Two Dot Punctuation", ':'),
-    ('׃', "Hebrew Punctuation Sof Pasuq", ':'),
-    ('˸', "Modifier Letter Raised Colon", ':'),
-    ('꞉', "Modifier Letter Colon", ':'),
-    ('∶', "Ratio", ':'),
-    ('ː', "Modifier Letter Triangular Colon", ':'),
-    ('ꓽ', "Lisu Letter Tone Mya Jeu", ':'),
-    ('︓', "Presentation Form For Vertical Colon", ':'),
-
-    ('！', "Fullwidth Exclamation Mark", '!'),
-    ('ǃ', "Latin Letter Retroflex Click", '!'),
-    ('ⵑ', "Tifinagh Letter Tuareg Yang", '!'),
-    ('︕', "Presentation Form For Vertical Exclamation Mark", '!'),
-
-    ('ʔ', "Latin Letter Glottal Stop", '?'),
-    ('Ɂ', "Latin Capital Letter Glottal Stop", '?'),
-    ('ॽ', "Devanagari Letter Glottal Stop", '?'),
-    ('Ꭾ', "Cherokee Letter He", '?'),
-    ('ꛫ', "Bamum Letter Ntuu", '?'),
-    ('？', "Fullwidth Question Mark", '?'),
-    ('︖', "Presentation Form For Vertical Question Mark", '?'),
-
-    ('𝅭', "Musical Symbol Combining Augmentation Dot", '.'),
-    ('․', "One Dot Leader", '.'),
-    ('܁', "Syriac Supralinear Full Stop", '.'),
-    ('܂', "Syriac Sublinear Full Stop", '.'),
-    ('꘎', "Vai Full Stop", '.'),
-    ('𐩐', "Kharoshthi Punctuation Dot", '.'),
-    ('٠', "Arabic-Indic Digit Zero", '.'),
-    ('۰', "Extended Arabic-Indic Digit Zero", '.'),
-    ('ꓸ', "Lisu Letter Tone Mya Ti", '.'),
-    ('·', "Middle Dot", '.'),
-    ('・', "Katakana Middle Dot", '.'),
-    ('･', "Halfwidth Katakana Middle Dot", '.'),
-    ('᛫', "Runic Single Punctuation", '.'),
-    ('·', "Greek Ano Teleia", '.'),
-    ('⸱', "Word Separator Middle Dot", '.'),
-    ('𐄁', "Aegean Word Separator Dot", '.'),
-    ('•', "Bullet", '.'),
-    ('‧', "Hyphenation Point", '.'),
-    ('∙', "Bullet Operator", '.'),
-    ('⋅', "Dot Operator", '.'),
-    ('ꞏ', "Latin Letter Sinological Dot", '.'),
-    ('ᐧ', "Canadian Syllabics Final Middle Dot", '.'),
-    ('ᐧ', "Canadian Syllabics Final Middle Dot", '.'),
-    ('．', "Fullwidth Full Stop", '.'),
-    ('。', "Ideographic Full Stop", '.'),
-    ('︒', "Presentation Form For Vertical Ideographic Full Stop", '.'),
-
-    ('՝', "Armenian Comma", '\''),
-    ('＇', "Fullwidth Apostrophe", '\''),
-    ('‘', "Left Single Quotation Mark", '\''),
-    ('’', "Right Single Quotation Mark", '\''),
-    ('‛', "Single High-Reversed-9 Quotation Mark", '\''),
-    ('′', "Prime", '\''),
-    ('‵', "Reversed Prime", '\''),
-    ('՚', "Armenian Apostrophe", '\''),
-    ('׳', "Hebrew Punctuation Geresh", '\''),
-    ('`', "Grave Accent", '\''),
-    ('`', "Greek Varia", '\''),
-    ('｀', "Fullwidth Grave Accent", '\''),
-    ('´', "Acute Accent", '\''),
-    ('΄', "Greek Tonos", '\''),
-    ('´', "Greek Oxia", '\''),
-    ('᾽', "Greek Koronis", '\''),
-    ('᾿', "Greek Psili", '\''),
-    ('῾', "Greek Dasia", '\''),
-    ('ʹ', "Modifier Letter Prime", '\''),
-    ('ʹ', "Greek Numeral Sign", '\''),
-    ('ˈ', "Modifier Letter Vertical Line", '\''),
-    ('ˊ', "Modifier Letter Acute Accent", '\''),
-    ('ˋ', "Modifier Letter Grave Accent", '\''),
-    ('˴', "Modifier Letter Middle Grave Accent", '\''),
-    ('ʻ', "Modifier Letter Turned Comma", '\''),
-    ('ʽ', "Modifier Letter Reversed Comma", '\''),
-    ('ʼ', "Modifier Letter Apostrophe", '\''),
-    ('ʾ', "Modifier Letter Right Half Ring", '\''),
-    ('ꞌ', "Latin Small Letter Saltillo", '\''),
-    ('י', "Hebrew Letter Yod", '\''),
-    ('ߴ', "Nko High Tone Apostrophe", '\''),
-    ('ߵ', "Nko Low Tone Apostrophe", '\''),
-    ('ᑊ', "Canadian Syllabics West-Cree P", '\''),
-    ('ᛌ', "Runic Letter Short-Twig-Sol S", '\''),
-    ('𖽑', "Miao Sign Aspiration", '\''),
-    ('𖽒', "Miao Sign Reformed Voicing", '\''),
-
-    ('᳓', "Vedic Sign Nihshvasa", '"'),
-    ('＂', "Fullwidth Quotation Mark", '"'),
-    ('“', "Left Double Quotation Mark", '"'),
-    ('”', "Right Double Quotation Mark", '"'),
-    ('‟', "Double High-Reversed-9 Quotation Mark", '"'),
-    ('″', "Double Prime", '"'),
-    ('‶', "Reversed Double Prime", '"'),
-    ('〃', "Ditto Mark", '"'),
-    ('״', "Hebrew Punctuation Gershayim", '"'),
-    ('˝', "Double Acute Accent", '"'),
-    ('ʺ', "Modifier Letter Double Prime", '"'),
-    ('˶', "Modifier Letter Middle Double Acute Accent", '"'),
-    ('˵', "Modifier Letter Middle Double Grave Accent", '"'),
-    ('ˮ', "Modifier Letter Double Apostrophe", '"'),
-    ('ײ', "Hebrew Ligature Yiddish Double Yod", '"'),
-    ('❞', "Heavy Double Comma Quotation Mark Ornament", '"'),
-    ('❝', "Heavy Double Turned Comma Quotation Mark Ornament", '"'),
-
-    ('（', "Fullwidth Left Parenthesis", '('),
-    ('❨', "Medium Left Parenthesis Ornament", '('),
-    ('﴾', "Ornate Left Parenthesis", '('),
-
-    ('）', "Fullwidth Right Parenthesis", ')'),
-    ('❩', "Medium Right Parenthesis Ornament", ')'),
-    ('﴿', "Ornate Right Parenthesis", ')'),
-
-    ('［', "Fullwidth Left Square Bracket", '['),
-    ('❲', "Light Left Tortoise Shell Bracket Ornament", '['),
-    ('「', "Left Corner Bracket", '['),
-    ('『', "Left White Corner Bracket", '['),
-    ('【', "Left Black Lenticular Bracket", '['),
-    ('〔', "Left Tortoise Shell Bracket", '['),
-    ('〖', "Left White Lenticular Bracket", '['),
-    ('〘', "Left White Tortoise Shell Bracket", '['),
-    ('〚', "Left White Square Bracket", '['),
-
-    ('］', "Fullwidth Right Square Bracket", ']'),
-    ('❳', "Light Right Tortoise Shell Bracket Ornament", ']'),
-    ('」', "Right Corner Bracket", ']'),
-    ('』', "Right White Corner Bracket", ']'),
-    ('】', "Right Black Lenticular Bracket", ']'),
-    ('〕', "Right Tortoise Shell Bracket", ']'),
-    ('〗', "Right White Lenticular Bracket", ']'),
-    ('〙', "Right White Tortoise Shell Bracket", ']'),
-    ('〛', "Right White Square Bracket", ']'),
-
-    ('❴', "Medium Left Curly Bracket Ornament", '{'),
-    ('𝄔', "Musical Symbol Brace", '{'),
-    ('｛', "Fullwidth Left Curly Bracket", '{'),
-
-    ('❵', "Medium Right Curly Bracket Ornament", '}'),
-    ('｝', "Fullwidth Right Curly Bracket", '}'),
-
-    ('⁎', "Low Asterisk", '*'),
-    ('٭', "Arabic Five Pointed Star", '*'),
-    ('∗', "Asterisk Operator", '*'),
-    ('𐌟', "Old Italic Letter Ess", '*'),
-    ('＊', "Fullwidth Asterisk", '*'),
-
-    ('᜵', "Philippine Single Punctuation", '/'),
-    ('⁁', "Caret Insertion Point", '/'),
-    ('∕', "Division Slash", '/'),
-    ('⁄', "Fraction Slash", '/'),
-    ('╱', "Box Drawings Light Diagonal Upper Right To Lower Left", '/'),
-    ('⟋', "Mathematical Rising Diagonal", '/'),
-    ('⧸', "Big Solidus", '/'),
-    ('𝈺', "Greek Instrumental Notation Symbol-47", '/'),
-    ('㇓', "CJK Stroke Sp", '/'),
-    ('〳', "Vertical Kana Repeat Mark Upper Half", '/'),
-    ('Ⳇ', "Coptic Capital Letter Old Coptic Esh", '/'),
-    ('ノ', "Katakana Letter No", '/'),
-    ('丿', "CJK Unified Ideograph-4E3F", '/'),
-    ('⼃', "Kangxi Radical Slash", '/'),
-    ('／', "Fullwidth Solidus", '/'),
-
-    ('＼', "Fullwidth Reverse Solidus", '\\'),
-    ('﹨', "Small Reverse Solidus", '\\'),
-    ('∖', "Set Minus", '\\'),
-    ('⟍', "Mathematical Falling Diagonal", '\\'),
-    ('⧵', "Reverse Solidus Operator", '\\'),
-    ('⧹', "Big Reverse Solidus", '\\'),
-    ('⧹', "Greek Vocal Notation Symbol-16", '\\'),
-    ('⧹', "Greek Instrumental Symbol-48", '\\'),
-    ('㇔', "CJK Stroke D", '\\'),
-    ('丶', "CJK Unified Ideograph-4E36", '\\'),
-    ('⼂', "Kangxi Radical Dot", '\\'),
-    ('、', "Ideographic Comma", '\\'),
-    ('ヽ', "Katakana Iteration Mark", '\\'),
-
-    ('ꝸ', "Latin Small Letter Um", '&'),
-    ('＆', "Fullwidth Ampersand", '&'),
-
-    ('᛭', "Runic Cross Punctuation", '+'),
-    ('➕', "Heavy Plus Sign", '+'),
-    ('𐊛', "Lycian Letter H", '+'),
-    ('﬩', "Hebrew Letter Alternative Plus Sign", '+'),
-    ('＋', "Fullwidth Plus Sign", '+'),
-
-    ('‹', "Single Left-Pointing Angle Quotation Mark", '<'),
-    ('❮', "Heavy Left-Pointing Angle Quotation Mark Ornament", '<'),
-    ('˂', "Modifier Letter Left Arrowhead", '<'),
-    ('𝈶', "Greek Instrumental Symbol-40", '<'),
-    ('ᐸ', "Canadian Syllabics Pa", '<'),
-    ('ᚲ', "Runic Letter Kauna", '<'),
-    ('❬', "Medium Left-Pointing Angle Bracket Ornament", '<'),
-    ('⟨', "Mathematical Left Angle Bracket", '<'),
-    ('〈', "Left-Pointing Angle Bracket", '<'),
-    ('〈', "Left Angle Bracket", '<'),
-    ('㇛', "CJK Stroke Pd", '<'),
-    ('く', "Hiragana Letter Ku", '<'),
-    ('𡿨', "CJK Unified Ideograph-21FE8", '<'),
-    ('《', "Left Double Angle Bracket", '<'),
-    ('＜', "Fullwidth Less-Than Sign", '<'),
-
-    ('᐀', "Canadian Syllabics Hyphen", '='),
-    ('⹀', "Double Hyphen", '='),
-    ('゠', "Katakana-Hiragana Double Hyphen", '='),
-    ('꓿', "Lisu Punctuation Full Stop", '='),
-    ('＝', "Fullwidth Equals Sign", '='),
-
-    ('›', "Single Right-Pointing Angle Quotation Mark", '>'),
-    ('❯', "Heavy Right-Pointing Angle Quotation Mark Ornament", '>'),
-    ('˃', "Modifier Letter Right Arrowhead", '>'),
-    ('𝈷', "Greek Instrumental Symbol-42", '>'),
-    ('ᐳ', "Canadian Syllabics Po", '>'),
-    ('𖼿', "Miao Letter Archaic Zza", '>'),
-    ('❭', "Medium Right-Pointing Angle Bracket Ornament", '>'),
-    ('⟩', "Mathematical Right Angle Bracket", '>'),
-    ('〉', "Right-Pointing Angle Bracket", '>'),
-    ('〉', "Right Angle Bracket", '>'),
-    ('》', "Right Double Angle Bracket", '>'),
-    ('＞', "Fullwidth Greater-Than Sign", '>'),
+pub(crate) const UNICODE_ARRAY: &[(char, &str, &str)] = &[
+    ('
', "Line Separator", " "),
+    ('
', "Paragraph Separator", " "),
+    (' ', "Ogham Space mark", " "),
+    (' ', "En Quad", " "),
+    (' ', "Em Quad", " "),
+    (' ', "En Space", " "),
+    (' ', "Em Space", " "),
+    (' ', "Three-Per-Em Space", " "),
+    (' ', "Four-Per-Em Space", " "),
+    (' ', "Six-Per-Em Space", " "),
+    (' ', "Punctuation Space", " "),
+    (' ', "Thin Space", " "),
+    (' ', "Hair Space", " "),
+    (' ', "Medium Mathematical Space", " "),
+    (' ', "No-Break Space", " "),
+    (' ', "Figure Space", " "),
+    (' ', "Narrow No-Break Space", " "),
+    ('　', "Ideographic Space", " "),
+
+    ('ߺ', "Nko Lajanyalan", "_"),
+    ('﹍', "Dashed Low Line", "_"),
+    ('﹎', "Centreline Low Line", "_"),
+    ('﹏', "Wavy Low Line", "_"),
+    ('＿', "Fullwidth Low Line", "_"),
+
+    ('‐', "Hyphen", "-"),
+    ('‑', "Non-Breaking Hyphen", "-"),
+    ('‒', "Figure Dash", "-"),
+    ('–', "En Dash", "-"),
+    ('—', "Em Dash", "-"),
+    ('﹘', "Small Em Dash", "-"),
+    ('۔', "Arabic Full Stop", "-"),
+    ('⁃', "Hyphen Bullet", "-"),
+    ('˗', "Modifier Letter Minus Sign", "-"),
+    ('−', "Minus Sign", "-"),
+    ('➖', "Heavy Minus Sign", "-"),
+    ('Ⲻ', "Coptic Letter Dialect-P Ni", "-"),
+    ('ー', "Katakana-Hiragana Prolonged Sound Mark", "-"),
+    ('－', "Fullwidth Hyphen-Minus", "-"),
+    ('―', "Horizontal Bar", "-"),
+    ('─', "Box Drawings Light Horizontal", "-"),
+    ('━', "Box Drawings Heavy Horizontal", "-"),
+    ('㇐', "CJK Stroke H", "-"),
+    ('ꟷ', "Latin Epigraphic Letter Sideways I", "-"),
+    ('ᅳ', "Hangul Jungseong Eu", "-"),
+    ('ㅡ', "Hangul Letter Eu", "-"),
+    ('一', "CJK Unified Ideograph-4E00", "-"),
+    ('⼀', "Kangxi Radical One", "-"),
+
+    ('؍', "Arabic Date Separator", ","),
+    ('٫', "Arabic Decimal Separator", ","),
+    ('‚', "Single Low-9 Quotation Mark", ","),
+    ('¸', "Cedilla", ","),
+    ('ꓹ', "Lisu Letter Tone Na Po", ","),
+    ('，', "Fullwidth Comma", ","),
+
+    (';', "Greek Question Mark", ";"),
+    ('；', "Fullwidth Semicolon", ";"),
+    ('︔', "Presentation Form For Vertical Semicolon", ";"),
+
+    ('ः', "Devanagari Sign Visarga", ":"),
+    ('ઃ', "Gujarati Sign Visarga", ":"),
+    ('：', "Fullwidth Colon", ":"),
+    ('։', "Armenian Full Stop", ":"),
+    ('܃', "Syriac Supralinear Colon", ":"),
+    ('܄', "Syriac Sublinear Colon", ":"),
+    ('᛬', "Runic Multiple Punctuation", ":"),
+    ('︰', "Presentation Form For Vertical Two Dot Leader", ":"),
+    ('᠃', "Mongolian Full Stop", ":"),
+    ('᠉', "Mongolian Manchu Full Stop", ":"),
+    ('⁚', "Two Dot Punctuation", ":"),
+    ('׃', "Hebrew Punctuation Sof Pasuq", ":"),
+    ('˸', "Modifier Letter Raised Colon", ":"),
+    ('꞉', "Modifier Letter Colon", ":"),
+    ('∶', "Ratio", ":"),
+    ('ː', "Modifier Letter Triangular Colon", ":"),
+    ('ꓽ', "Lisu Letter Tone Mya Jeu", ":"),
+    ('︓', "Presentation Form For Vertical Colon", ":"),
+
+    ('！', "Fullwidth Exclamation Mark", "!"),
+    ('ǃ', "Latin Letter Retroflex Click", "!"),
+    ('ⵑ', "Tifinagh Letter Tuareg Yang", "!"),
+    ('︕', "Presentation Form For Vertical Exclamation Mark", "!"),
+
+    ('ʔ', "Latin Letter Glottal Stop", "?"),
+    ('Ɂ', "Latin Capital Letter Glottal Stop", "?"),
+    ('ॽ', "Devanagari Letter Glottal Stop", "?"),
+    ('Ꭾ', "Cherokee Letter He", "?"),
+    ('ꛫ', "Bamum Letter Ntuu", "?"),
+    ('？', "Fullwidth Question Mark", "?"),
+    ('︖', "Presentation Form For Vertical Question Mark", "?"),
+
+    ('𝅭', "Musical Symbol Combining Augmentation Dot", "."),
+    ('․', "One Dot Leader", "."),
+    ('܁', "Syriac Supralinear Full Stop", "."),
+    ('܂', "Syriac Sublinear Full Stop", "."),
+    ('꘎', "Vai Full Stop", "."),
+    ('𐩐', "Kharoshthi Punctuation Dot", "."),
+    ('٠', "Arabic-Indic Digit Zero", "."),
+    ('۰', "Extended Arabic-Indic Digit Zero", "."),
+    ('ꓸ', "Lisu Letter Tone Mya Ti", "."),
+    ('·', "Middle Dot", "."),
+    ('・', "Katakana Middle Dot", "."),
+    ('･', "Halfwidth Katakana Middle Dot", "."),
+    ('᛫', "Runic Single Punctuation", "."),
+    ('·', "Greek Ano Teleia", "."),
+    ('⸱', "Word Separator Middle Dot", "."),
+    ('𐄁', "Aegean Word Separator Dot", "."),
+    ('•', "Bullet", "."),
+    ('‧', "Hyphenation Point", "."),
+    ('∙', "Bullet Operator", "."),
+    ('⋅', "Dot Operator", "."),
+    ('ꞏ', "Latin Letter Sinological Dot", "."),
+    ('ᐧ', "Canadian Syllabics Final Middle Dot", "."),
+    ('ᐧ', "Canadian Syllabics Final Middle Dot", "."),
+    ('．', "Fullwidth Full Stop", "."),
+    ('。', "Ideographic Full Stop", "."),
+    ('︒', "Presentation Form For Vertical Ideographic Full Stop", "."),
+
+    ('՝', "Armenian Comma", "\'"),
+    ('＇', "Fullwidth Apostrophe", "\'"),
+    ('‘', "Left Single Quotation Mark", "\'"),
+    ('’', "Right Single Quotation Mark", "\'"),
+    ('‛', "Single High-Reversed-9 Quotation Mark", "\'"),
+    ('′', "Prime", "\'"),
+    ('‵', "Reversed Prime", "\'"),
+    ('՚', "Armenian Apostrophe", "\'"),
+    ('׳', "Hebrew Punctuation Geresh", "\'"),
+    ('`', "Grave Accent", "\'"),
+    ('`', "Greek Varia", "\'"),
+    ('｀', "Fullwidth Grave Accent", "\'"),
+    ('´', "Acute Accent", "\'"),
+    ('΄', "Greek Tonos", "\'"),
+    ('´', "Greek Oxia", "\'"),
+    ('᾽', "Greek Koronis", "\'"),
+    ('᾿', "Greek Psili", "\'"),
+    ('῾', "Greek Dasia", "\'"),
+    ('ʹ', "Modifier Letter Prime", "\'"),
+    ('ʹ', "Greek Numeral Sign", "\'"),
+    ('ˈ', "Modifier Letter Vertical Line", "\'"),
+    ('ˊ', "Modifier Letter Acute Accent", "\'"),
+    ('ˋ', "Modifier Letter Grave Accent", "\'"),
+    ('˴', "Modifier Letter Middle Grave Accent", "\'"),
+    ('ʻ', "Modifier Letter Turned Comma", "\'"),
+    ('ʽ', "Modifier Letter Reversed Comma", "\'"),
+    ('ʼ', "Modifier Letter Apostrophe", "\'"),
+    ('ʾ', "Modifier Letter Right Half Ring", "\'"),
+    ('ꞌ', "Latin Small Letter Saltillo", "\'"),
+    ('י', "Hebrew Letter Yod", "\'"),
+    ('ߴ', "Nko High Tone Apostrophe", "\'"),
+    ('ߵ', "Nko Low Tone Apostrophe", "\'"),
+    ('ᑊ', "Canadian Syllabics West-Cree P", "\'"),
+    ('ᛌ', "Runic Letter Short-Twig-Sol S", "\'"),
+    ('𖽑', "Miao Sign Aspiration", "\'"),
+    ('𖽒', "Miao Sign Reformed Voicing", "\'"),
+
+    ('᳓', "Vedic Sign Nihshvasa", "\""),
+    ('＂', "Fullwidth Quotation Mark", "\""),
+    ('“', "Left Double Quotation Mark", "\""),
+    ('”', "Right Double Quotation Mark", "\""),
+    ('‟', "Double High-Reversed-9 Quotation Mark", "\""),
+    ('″', "Double Prime", "\""),
+    ('‶', "Reversed Double Prime", "\""),
+    ('〃', "Ditto Mark", "\""),
+    ('״', "Hebrew Punctuation Gershayim", "\""),
+    ('˝', "Double Acute Accent", "\""),
+    ('ʺ', "Modifier Letter Double Prime", "\""),
+    ('˶', "Modifier Letter Middle Double Acute Accent", "\""),
+    ('˵', "Modifier Letter Middle Double Grave Accent", "\""),
+    ('ˮ', "Modifier Letter Double Apostrophe", "\""),
+    ('ײ', "Hebrew Ligature Yiddish Double Yod", "\""),
+    ('❞', "Heavy Double Comma Quotation Mark Ornament", "\""),
+    ('❝', "Heavy Double Turned Comma Quotation Mark Ornament", "\""),
+
+    ('（', "Fullwidth Left Parenthesis", "("),
+    ('❨', "Medium Left Parenthesis Ornament", "("),
+    ('﴾', "Ornate Left Parenthesis", "("),
+
+    ('）', "Fullwidth Right Parenthesis", ")"),
+    ('❩', "Medium Right Parenthesis Ornament", ")"),
+    ('﴿', "Ornate Right Parenthesis", ")"),
+
+    ('［', "Fullwidth Left Square Bracket", "["),
+    ('❲', "Light Left Tortoise Shell Bracket Ornament", "["),
+    ('「', "Left Corner Bracket", "["),
+    ('『', "Left White Corner Bracket", "["),
+    ('【', "Left Black Lenticular Bracket", "["),
+    ('〔', "Left Tortoise Shell Bracket", "["),
+    ('〖', "Left White Lenticular Bracket", "["),
+    ('〘', "Left White Tortoise Shell Bracket", "["),
+    ('〚', "Left White Square Bracket", "["),
+
+    ('］', "Fullwidth Right Square Bracket", "]"),
+    ('❳', "Light Right Tortoise Shell Bracket Ornament", "]"),
+    ('」', "Right Corner Bracket", "]"),
+    ('』', "Right White Corner Bracket", "]"),
+    ('】', "Right Black Lenticular Bracket", "]"),
+    ('〕', "Right Tortoise Shell Bracket", "]"),
+    ('〗', "Right White Lenticular Bracket", "]"),
+    ('〙', "Right White Tortoise Shell Bracket", "]"),
+    ('〛', "Right White Square Bracket", "]"),
+
+    ('❴', "Medium Left Curly Bracket Ornament", "{"),
+    ('𝄔', "Musical Symbol Brace", "{"),
+    ('｛', "Fullwidth Left Curly Bracket", "{"),
+
+    ('❵', "Medium Right Curly Bracket Ornament", "}"),
+    ('｝', "Fullwidth Right Curly Bracket", "}"),
+
+    ('⁎', "Low Asterisk", "*"),
+    ('٭', "Arabic Five Pointed Star", "*"),
+    ('∗', "Asterisk Operator", "*"),
+    ('𐌟', "Old Italic Letter Ess", "*"),
+    ('＊', "Fullwidth Asterisk", "*"),
+
+    ('᜵', "Philippine Single Punctuation", "/"),
+    ('⁁', "Caret Insertion Point", "/"),
+    ('∕', "Division Slash", "/"),
+    ('⁄', "Fraction Slash", "/"),
+    ('╱', "Box Drawings Light Diagonal Upper Right To Lower Left", "/"),
+    ('⟋', "Mathematical Rising Diagonal", "/"),
+    ('⧸', "Big Solidus", "/"),
+    ('𝈺', "Greek Instrumental Notation Symbol-47", "/"),
+    ('㇓', "CJK Stroke Sp", "/"),
+    ('〳', "Vertical Kana Repeat Mark Upper Half", "/"),
+    ('Ⳇ', "Coptic Capital Letter Old Coptic Esh", "/"),
+    ('ノ', "Katakana Letter No", "/"),
+    ('丿', "CJK Unified Ideograph-4E3F", "/"),
+    ('⼃', "Kangxi Radical Slash", "/"),
+    ('／', "Fullwidth Solidus", "/"),
+
+    ('＼', "Fullwidth Reverse Solidus", "\\"),
+    ('﹨', "Small Reverse Solidus", "\\"),
+    ('∖', "Set Minus", "\\"),
+    ('⟍', "Mathematical Falling Diagonal", "\\"),
+    ('⧵', "Reverse Solidus Operator", "\\"),
+    ('⧹', "Big Reverse Solidus", "\\"),
+    ('⧹', "Greek Vocal Notation Symbol-16", "\\"),
+    ('⧹', "Greek Instrumental Symbol-48", "\\"),
+    ('㇔', "CJK Stroke D", "\\"),
+    ('丶', "CJK Unified Ideograph-4E36", "\\"),
+    ('⼂', "Kangxi Radical Dot", "\\"),
+    ('、', "Ideographic Comma", "\\"),
+    ('ヽ', "Katakana Iteration Mark", "\\"),
+
+    ('ꝸ', "Latin Small Letter Um", "&"),
+    ('＆', "Fullwidth Ampersand", "&"),
+
+    ('᛭', "Runic Cross Punctuation", "+"),
+    ('➕', "Heavy Plus Sign", "+"),
+    ('𐊛', "Lycian Letter H", "+"),
+    ('﬩', "Hebrew Letter Alternative Plus Sign", "+"),
+    ('＋', "Fullwidth Plus Sign", "+"),
+
+    ('‹', "Single Left-Pointing Angle Quotation Mark", "<"),
+    ('❮', "Heavy Left-Pointing Angle Quotation Mark Ornament", "<"),
+    ('˂', "Modifier Letter Left Arrowhead", "<"),
+    ('𝈶', "Greek Instrumental Symbol-40", "<"),
+    ('ᐸ', "Canadian Syllabics Pa", "<"),
+    ('ᚲ', "Runic Letter Kauna", "<"),
+    ('❬', "Medium Left-Pointing Angle Bracket Ornament", "<"),
+    ('⟨', "Mathematical Left Angle Bracket", "<"),
+    ('〈', "Left-Pointing Angle Bracket", "<"),
+    ('〈', "Left Angle Bracket", "<"),
+    ('㇛', "CJK Stroke Pd", "<"),
+    ('く', "Hiragana Letter Ku", "<"),
+    ('𡿨', "CJK Unified Ideograph-21FE8", "<"),
+    ('《', "Left Double Angle Bracket", "<"),
+    ('＜', "Fullwidth Less-Than Sign", "<"),
+
+    ('᐀', "Canadian Syllabics Hyphen", "="),
+    ('⹀', "Double Hyphen", "="),
+    ('゠', "Katakana-Hiragana Double Hyphen", "="),
+    ('꓿', "Lisu Punctuation Full Stop", "="),
+    ('＝', "Fullwidth Equals Sign", "="),
+
+    ('›', "Single Right-Pointing Angle Quotation Mark", ">"),
+    ('❯', "Heavy Right-Pointing Angle Quotation Mark Ornament", ">"),
+    ('˃', "Modifier Letter Right Arrowhead", ">"),
+    ('𝈷', "Greek Instrumental Symbol-42", ">"),
+    ('ᐳ', "Canadian Syllabics Po", ">"),
+    ('𖼿', "Miao Letter Archaic Zza", ">"),
+    ('❭', "Medium Right-Pointing Angle Bracket Ornament", ">"),
+    ('⟩', "Mathematical Right Angle Bracket", ">"),
+    ('〉', "Right-Pointing Angle Bracket", ">"),
+    ('〉', "Right Angle Bracket", ">"),
+    ('》', "Right Double Angle Bracket", ">"),
+    ('＞', "Fullwidth Greater-Than Sign", ">"),
+    ('⩵', "Two Consecutive Equals Signs", "==")
 ];
 
 // FIXME: the lexer could be used to turn the ASCII version of unicode homoglyphs, instead of
 // keeping the substitution token in this table. Ideally, this should be inside `rustc_lexer`.
 // However, we should first remove compound tokens like `<<` from `rustc_lexer`, and then add
 // fancier error recovery to it, as there will be less overall work to do this way.
-const ASCII_ARRAY: &[(char, &str, Option<token::TokenKind>)] = &[
-    (' ', "Space", None),
-    ('_', "Underscore", Some(token::Ident(kw::Underscore, false))),
-    ('-', "Minus/Hyphen", Some(token::BinOp(token::Minus))),
-    (',', "Comma", Some(token::Comma)),
-    (';', "Semicolon", Some(token::Semi)),
-    (':', "Colon", Some(token::Colon)),
-    ('!', "Exclamation Mark", Some(token::Not)),
-    ('?', "Question Mark", Some(token::Question)),
-    ('.', "Period", Some(token::Dot)),
-    ('(', "Left Parenthesis", Some(token::OpenDelim(Delimiter::Parenthesis))),
-    (')', "Right Parenthesis", Some(token::CloseDelim(Delimiter::Parenthesis))),
-    ('[', "Left Square Bracket", Some(token::OpenDelim(Delimiter::Bracket))),
-    (']', "Right Square Bracket", Some(token::CloseDelim(Delimiter::Bracket))),
-    ('{', "Left Curly Brace", Some(token::OpenDelim(Delimiter::Brace))),
-    ('}', "Right Curly Brace", Some(token::CloseDelim(Delimiter::Brace))),
-    ('*', "Asterisk", Some(token::BinOp(token::Star))),
-    ('/', "Slash", Some(token::BinOp(token::Slash))),
-    ('\\', "Backslash", None),
-    ('&', "Ampersand", Some(token::BinOp(token::And))),
-    ('+', "Plus Sign", Some(token::BinOp(token::Plus))),
-    ('<', "Less-Than Sign", Some(token::Lt)),
-    ('=', "Equals Sign", Some(token::Eq)),
-    ('>', "Greater-Than Sign", Some(token::Gt)),
+const ASCII_ARRAY: &[(&str, &str, Option<token::TokenKind>)] = &[
+    (" ", "Space", None),
+    ("_", "Underscore", Some(token::Ident(kw::Underscore, false))),
+    ("-", "Minus/Hyphen", Some(token::BinOp(token::Minus))),
+    (",", "Comma", Some(token::Comma)),
+    (";", "Semicolon", Some(token::Semi)),
+    (":", "Colon", Some(token::Colon)),
+    ("!", "Exclamation Mark", Some(token::Not)),
+    ("?", "Question Mark", Some(token::Question)),
+    (".", "Period", Some(token::Dot)),
+    ("(", "Left Parenthesis", Some(token::OpenDelim(Delimiter::Parenthesis))),
+    (")", "Right Parenthesis", Some(token::CloseDelim(Delimiter::Parenthesis))),
+    ("[", "Left Square Bracket", Some(token::OpenDelim(Delimiter::Bracket))),
+    ("]", "Right Square Bracket", Some(token::CloseDelim(Delimiter::Bracket))),
+    ("{", "Left Curly Brace", Some(token::OpenDelim(Delimiter::Brace))),
+    ("}", "Right Curly Brace", Some(token::CloseDelim(Delimiter::Brace))),
+    ("*", "Asterisk", Some(token::BinOp(token::Star))),
+    ("/", "Slash", Some(token::BinOp(token::Slash))),
+    ("\\", "Backslash", None),
+    ("&", "Ampersand", Some(token::BinOp(token::And))),
+    ("+", "Plus Sign", Some(token::BinOp(token::Plus))),
+    ("<", "Less-Than Sign", Some(token::Lt)),
+    ("=", "Equals Sign", Some(token::Eq)),
+    ("==", "Double Equals Sign", Some(token::EqEq)),
+    (">", "Greater-Than Sign", Some(token::Gt)),
     // FIXME: Literals are already lexed by this point, so we can't recover gracefully just by
     // spitting the correct token out.
-    ('\'', "Single Quote", None),
-    ('"', "Quotation Mark", None),
+    ("\'", "Single Quote", None),
+    ("\"", "Quotation Mark", None),
 ];
 
 pub(super) fn check_for_substitution<'a>(
@@ -339,11 +341,11 @@ pub(super) fn check_for_substitution<'a>(
     err: &mut Diagnostic,
     count: usize,
 ) -> Option<token::TokenKind> {
-    let &(_u_char, u_name, ascii_char) = UNICODE_ARRAY.iter().find(|&&(c, _, _)| c == ch)?;
+    let &(_, u_name, ascii_str) = UNICODE_ARRAY.iter().find(|&&(c, _, _)| c == ch)?;
 
     let span = Span::with_root_ctxt(pos, pos + Pos::from_usize(ch.len_utf8() * count));
 
-    let Some((_ascii_char, ascii_name, token)) = ASCII_ARRAY.iter().find(|&&(c, _, _)| c == ascii_char) else {
+    let Some((_, ascii_name, token)) = ASCII_ARRAY.iter().find(|&&(s, _, _)| s == ascii_str) else {
         let msg = format!("substitution character not found for '{}'", ch);
         reader.sess.span_diagnostic.span_bug_no_panic(span, &msg);
         return None;
@@ -354,7 +356,7 @@ pub(super) fn check_for_substitution<'a>(
         let msg = format!(
             "Unicode characters '“' (Left Double Quotation Mark) and \
              '”' (Right Double Quotation Mark) look like '{}' ({}), but are not",
-            ascii_char, ascii_name
+            ascii_str, ascii_name
         );
         err.span_suggestion(
             Span::with_root_ctxt(
@@ -368,12 +370,12 @@ pub(super) fn check_for_substitution<'a>(
     } else {
         let msg = format!(
             "Unicode character '{}' ({}) looks like '{}' ({}), but it is not",
-            ch, u_name, ascii_char, ascii_name
+            ch, u_name, ascii_str, ascii_name
         );
         err.span_suggestion(
             span,
             &msg,
-            ascii_char.to_string().repeat(count),
+            ascii_str.to_string().repeat(count),
             Applicability::MaybeIncorrect,
         );
     }
diff --git a/compiler/rustc_parse/src/parser/expr.rs b/compiler/rustc_parse/src/parser/expr.rs
index d58afcd4c9f..bf93a89f065 100644
--- a/compiler/rustc_parse/src/parser/expr.rs
+++ b/compiler/rustc_parse/src/parser/expr.rs
@@ -1353,9 +1353,6 @@ impl<'a> Parser<'a> {
                 err.span_label(sp, "while parsing this `loop` expression");
                 err
             })
-        } else if self.eat_keyword(kw::Continue) {
-            let kind = ExprKind::Continue(self.eat_label());
-            Ok(self.mk_expr(lo.to(self.prev_token.span), kind))
         } else if self.eat_keyword(kw::Match) {
             let match_sp = self.prev_token.span;
             self.parse_match_expr().map_err(|mut err| {
@@ -1379,6 +1376,8 @@ impl<'a> Parser<'a> {
             self.parse_try_block(lo)
         } else if self.eat_keyword(kw::Return) {
             self.parse_return_expr()
+        } else if self.eat_keyword(kw::Continue) {
+            self.parse_continue_expr(lo)
         } else if self.eat_keyword(kw::Break) {
             self.parse_break_expr()
         } else if self.eat_keyword(kw::Yield) {
@@ -1715,10 +1714,10 @@ impl<'a> Parser<'a> {
     fn parse_break_expr(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.prev_token.span;
         let mut label = self.eat_label();
-        let kind = if label.is_some() && self.token == token::Colon {
+        let kind = if self.token == token::Colon && let Some(label) = label.take() {
             // The value expression can be a labeled loop, see issue #86948, e.g.:
             // `loop { break 'label: loop { break 'label 42; }; }`
-            let lexpr = self.parse_labeled_expr(label.take().unwrap(), true)?;
+            let lexpr = self.parse_labeled_expr(label, true)?;
             self.sess.emit_err(LabeledLoopInBreak {
                 span: lexpr.span,
                 sub: WrapExpressionInParentheses {
@@ -1730,8 +1729,8 @@ impl<'a> Parser<'a> {
         } else if self.token != token::OpenDelim(Delimiter::Brace)
             || !self.restrictions.contains(Restrictions::NO_STRUCT_LITERAL)
         {
-            let expr = self.parse_expr_opt()?;
-            if let Some(expr) = &expr {
+            let mut expr = self.parse_expr_opt()?;
+            if let Some(expr) = &mut expr {
                 if label.is_some()
                     && matches!(
                         expr.kind,
@@ -1749,7 +1748,19 @@ impl<'a> Parser<'a> {
                         BuiltinLintDiagnostics::BreakWithLabelAndLoop(expr.span),
                     );
                 }
+
+                // Recover `break label aaaaa`
+                if self.may_recover()
+                    && let ExprKind::Path(None, p) = &expr.kind
+                    && let [segment] = &*p.segments
+                    && let &ast::PathSegment { ident, args: None, .. } = segment
+                    && let Some(next) = self.parse_expr_opt()?
+                {
+                    label = Some(self.recover_ident_into_label(ident));
+                    *expr = next;
+                }
             }
+
             expr
         } else {
             None
@@ -1758,6 +1769,23 @@ impl<'a> Parser<'a> {
         self.maybe_recover_from_bad_qpath(expr)
     }
 
+    /// Parse `"continue" label?`.
+    fn parse_continue_expr(&mut self, lo: Span) -> PResult<'a, P<Expr>> {
+        let mut label = self.eat_label();
+
+        // Recover `continue label` -> `continue 'label`
+        if self.may_recover()
+            && label.is_none()
+            && let Some((ident, _)) = self.token.ident()
+        {
+            self.bump();
+            label = Some(self.recover_ident_into_label(ident));
+        }
+
+        let kind = ExprKind::Continue(label);
+        Ok(self.mk_expr(lo.to(self.prev_token.span), kind))
+    }
+
     /// Parse `"yield" expr?`.
     fn parse_yield_expr(&mut self) -> PResult<'a, P<Expr>> {
         let lo = self.prev_token.span;
@@ -3046,6 +3074,25 @@ impl<'a> Parser<'a> {
         false
     }
 
+    /// Converts an ident into 'label and emits an "expected a label, found an identifier" error.
+    fn recover_ident_into_label(&mut self, ident: Ident) -> Label {
+        // Convert `label` -> `'label`,
+        // so that nameres doesn't complain about non-existing label
+        let label = format!("'{}", ident.name);
+        let ident = Ident { name: Symbol::intern(&label), span: ident.span };
+
+        self.struct_span_err(ident.span, "expected a label, found an identifier")
+            .span_suggestion(
+                ident.span,
+                "labels start with a tick",
+                label,
+                Applicability::MachineApplicable,
+            )
+            .emit();
+
+        Label { ident }
+    }
+
     /// Parses `ident (COLON expr)?`.
     fn parse_expr_field(&mut self) -> PResult<'a, ExprField> {
         let attrs = self.parse_outer_attributes()?;
diff --git a/compiler/rustc_parse/src/parser/ty.rs b/compiler/rustc_parse/src/parser/ty.rs
index a6f702e5428..1766b0293de 100644
--- a/compiler/rustc_parse/src/parser/ty.rs
+++ b/compiler/rustc_parse/src/parser/ty.rs
@@ -727,11 +727,13 @@ impl<'a> Parser<'a> {
         let mut bounds = Vec::new();
         let mut negative_bounds = Vec::new();
 
+        // In addition to looping while we find generic bounds:
+        // We continue even if we find a keyword. This is necessary for error recovery on,
+        // for example, `impl fn()`. The only keyword that can go after generic bounds is
+        // `where`, so stop if it's it.
+        // We also continue if we find types (not traits), again for error recovery.
         while self.can_begin_bound()
-            // Continue even if we find a keyword.
-            // This is necessary for error recover on, for example, `impl fn()`.
-            //
-            // The only keyword that can go after generic bounds is `where`, so stop if it's it.
+            || self.token.can_begin_type()
             || (self.token.is_reserved_ident() && !self.token.is_keyword(kw::Where))
         {
             if self.token.is_keyword(kw::Dyn) {
@@ -939,6 +941,36 @@ impl<'a> Parser<'a> {
             && let Some(path) = self.recover_path_from_fn()
         {
             path
+        } else if !self.token.is_path_start() && self.token.can_begin_type() {
+            let ty = self.parse_ty_no_plus()?;
+            // Instead of finding a path (a trait), we found a type.
+            let mut err = self.struct_span_err(ty.span, "expected a trait, found type");
+
+            // If we can recover, try to extract a path from the type. Note
+            // that we do not use the try operator when parsing the type because
+            // if it fails then we get a parser error which we don't want (we're trying
+            // to recover from errors, not make more).
+            let path = if self.may_recover()
+                && matches!(ty.kind, TyKind::Ptr(..) | TyKind::Ref(..))
+                && let TyKind::Path(_, path) = &ty.peel_refs().kind {
+                // Just get the indirection part of the type.
+                let span = ty.span.until(path.span);
+
+                err.span_suggestion_verbose(
+                    span,
+                    "consider removing the indirection",
+                    "",
+                    Applicability::MaybeIncorrect,
+                );
+
+                path.clone()
+            } else {
+                return Err(err);
+            };
+
+            err.emit();
+
+            path
         } else {
             self.parse_path(PathStyle::Type)?
         };
diff --git a/compiler/rustc_parse_format/src/lib.rs b/compiler/rustc_parse_format/src/lib.rs
index 1eb227503f2..7b016cadac3 100644
--- a/compiler/rustc_parse_format/src/lib.rs
+++ b/compiler/rustc_parse_format/src/lib.rs
@@ -20,7 +20,6 @@ pub use Flag::*;
 pub use Piece::*;
 pub use Position::*;
 
-use rustc_lexer::unescape;
 use std::iter;
 use std::str;
 use std::string;
@@ -314,11 +313,12 @@ impl<'a> Parser<'a> {
         append_newline: bool,
         mode: ParseMode,
     ) -> Parser<'a> {
-        let input_string_kind = find_width_map_from_snippet(s, snippet, style);
+        let input_string_kind = find_width_map_from_snippet(snippet, style);
         let (width_map, is_literal) = match input_string_kind {
             InputStringKind::Literal { width_mappings } => (width_mappings, true),
             InputStringKind::NotALiteral => (Vec::new(), false),
         };
+
         Parser {
             mode,
             input: s,
@@ -856,7 +856,6 @@ impl<'a> Parser<'a> {
 /// written code (code snippet) and the `InternedString` that gets processed in the `Parser`
 /// in order to properly synthesise the intra-string `Span`s for error diagnostics.
 fn find_width_map_from_snippet(
-    input: &str,
     snippet: Option<string::String>,
     str_style: Option<usize>,
 ) -> InputStringKind {
@@ -869,27 +868,8 @@ fn find_width_map_from_snippet(
         return InputStringKind::Literal { width_mappings: Vec::new() };
     }
 
-    // Strip quotes.
     let snippet = &snippet[1..snippet.len() - 1];
 
-    // Macros like `println` add a newline at the end. That technically doens't make them "literals" anymore, but it's fine
-    // since we will never need to point our spans there, so we lie about it here by ignoring it.
-    // Since there might actually be newlines in the source code, we need to normalize away all trailing newlines.
-    // If we only trimmed it off the input, `format!("\n")` would cause a mismatch as here we they actually match up.
-    // Alternatively, we could just count the trailing newlines and only trim one from the input if they don't match up.
-    let input_no_nl = input.trim_end_matches('\n');
-    let Ok(unescaped) = unescape_string(snippet) else {
-        return InputStringKind::NotALiteral;
-    };
-
-    let unescaped_no_nl = unescaped.trim_end_matches('\n');
-
-    if unescaped_no_nl != input_no_nl {
-        // The source string that we're pointing at isn't our input, so spans pointing at it will be incorrect.
-        // This can for example happen with proc macros that respan generated literals.
-        return InputStringKind::NotALiteral;
-    }
-
     let mut s = snippet.char_indices();
     let mut width_mappings = vec![];
     while let Some((pos, c)) = s.next() {
@@ -972,19 +952,6 @@ fn find_width_map_from_snippet(
     InputStringKind::Literal { width_mappings }
 }
 
-fn unescape_string(string: &str) -> Result<string::String, unescape::EscapeError> {
-    let mut buf = string::String::new();
-    let mut error = Ok(());
-    unescape::unescape_literal(string, unescape::Mode::Str, &mut |_, unescaped_char| {
-        match unescaped_char {
-            Ok(c) => buf.push(c),
-            Err(err) => error = Err(err),
-        }
-    });
-
-    error.map(|_| buf)
-}
-
 // Assert a reasonable size for `Piece`
 #[cfg(all(target_arch = "x86_64", target_pointer_width = "64"))]
 rustc_data_structures::static_assert_size!(Piece<'_>, 16);
diff --git a/compiler/rustc_passes/src/entry.rs b/compiler/rustc_passes/src/entry.rs
index 5885f45ae45..b327ba63330 100644
--- a/compiler/rustc_passes/src/entry.rs
+++ b/compiler/rustc_passes/src/entry.rs
@@ -195,7 +195,7 @@ fn no_main_err(tcx: TyCtxt<'_>, visitor: &EntryContext<'_>) {
 
     // There is no main function.
     let mut has_filename = true;
-    let filename = tcx.sess.local_crate_source_file.clone().unwrap_or_else(|| {
+    let filename = tcx.sess.local_crate_source_file().unwrap_or_else(|| {
         has_filename = false;
         Default::default()
     });
diff --git a/compiler/rustc_passes/src/lib_features.rs b/compiler/rustc_passes/src/lib_features.rs
index b5843c0ae48..4c6a9b23fdf 100644
--- a/compiler/rustc_passes/src/lib_features.rs
+++ b/compiler/rustc_passes/src/lib_features.rs
@@ -137,6 +137,12 @@ impl<'tcx> Visitor<'tcx> for LibFeatureCollector<'tcx> {
 }
 
 fn lib_features(tcx: TyCtxt<'_>, (): ()) -> LibFeatures {
+    // If `staged_api` is not enabled then we aren't allowed to define lib
+    // features; there is no point collecting them.
+    if !tcx.features().staged_api {
+        return new_lib_features();
+    }
+
     let mut collector = LibFeatureCollector::new(tcx);
     tcx.hir().walk_attributes(&mut collector);
     collector.lib_features
diff --git a/compiler/rustc_privacy/src/lib.rs b/compiler/rustc_privacy/src/lib.rs
index fb55bb4afaa..9a5d3cceb91 100644
--- a/compiler/rustc_privacy/src/lib.rs
+++ b/compiler/rustc_privacy/src/lib.rs
@@ -1,6 +1,5 @@
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(associated_type_defaults)]
-#![feature(control_flow_enum)]
 #![feature(rustc_private)]
 #![feature(try_blocks)]
 #![feature(let_chains)]
@@ -112,7 +111,11 @@ where
     fn visit_trait(&mut self, trait_ref: TraitRef<'tcx>) -> ControlFlow<V::BreakTy> {
         let TraitRef { def_id, substs, .. } = trait_ref;
         self.def_id_visitor.visit_def_id(def_id, "trait", &trait_ref.print_only_trait_path())?;
-        if self.def_id_visitor.shallow() { ControlFlow::CONTINUE } else { substs.visit_with(self) }
+        if self.def_id_visitor.shallow() {
+            ControlFlow::Continue(())
+        } else {
+            substs.visit_with(self)
+        }
     }
 
     fn visit_projection_ty(&mut self, projection: ty::AliasTy<'tcx>) -> ControlFlow<V::BreakTy> {
@@ -131,7 +134,7 @@ where
             };
         self.visit_trait(trait_ref)?;
         if self.def_id_visitor.shallow() {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         } else {
             assoc_substs.iter().try_for_each(|subst| subst.visit_with(self))
         }
@@ -155,7 +158,7 @@ where
                 ty,
                 _region,
             ))) => ty.visit_with(self),
-            ty::PredicateKind::Clause(ty::Clause::RegionOutlives(..)) => ControlFlow::CONTINUE,
+            ty::PredicateKind::Clause(ty::Clause::RegionOutlives(..)) => ControlFlow::Continue(()),
             ty::PredicateKind::ConstEvaluatable(ct) => ct.visit_with(self),
             ty::PredicateKind::WellFormed(arg) => arg.visit_with(self),
             _ => bug!("unexpected predicate: {:?}", predicate),
@@ -189,7 +192,7 @@ where
             | ty::Generator(def_id, ..) => {
                 self.def_id_visitor.visit_def_id(def_id, "type", &ty)?;
                 if self.def_id_visitor.shallow() {
-                    return ControlFlow::CONTINUE;
+                    return ControlFlow::Continue(());
                 }
                 // Default type visitor doesn't visit signatures of fn types.
                 // Something like `fn() -> Priv {my_func}` is considered a private type even if
@@ -214,7 +217,7 @@ where
                     // as visible/reachable even if both `Type` and `Trait` are private.
                     // Ideally, associated types should be substituted in the same way as
                     // free type aliases, but this isn't done yet.
-                    return ControlFlow::CONTINUE;
+                    return ControlFlow::Continue(());
                 }
                 // This will also visit substs if necessary, so we don't need to recurse.
                 return self.visit_projection_ty(proj);
@@ -274,7 +277,7 @@ where
         }
 
         if self.def_id_visitor.shallow() {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         } else {
             ty.super_visit_with(self)
         }
@@ -319,7 +322,7 @@ impl<'a, 'tcx, VL: VisibilityLike> DefIdVisitor<'tcx> for FindMin<'a, 'tcx, VL>
         if let Some(def_id) = def_id.as_local() {
             self.min = VL::new_min(self, def_id);
         }
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
 
@@ -881,7 +884,7 @@ impl<'tcx> DefIdVisitor<'tcx> for ReachEverythingInTheInterfaceVisitor<'_, 'tcx>
                 self.ev.update(def_id, self.level);
             }
         }
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
 
@@ -1368,9 +1371,9 @@ impl<'tcx> DefIdVisitor<'tcx> for TypePrivacyVisitor<'tcx> {
         descr: &dyn fmt::Display,
     ) -> ControlFlow<Self::BreakTy> {
         if self.check_def_id(def_id, kind, descr) {
-            ControlFlow::BREAK
+            ControlFlow::Break(())
         } else {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         }
     }
 }
@@ -1865,9 +1868,9 @@ impl<'tcx> DefIdVisitor<'tcx> for SearchInterfaceForPrivateItemsVisitor<'tcx> {
         descr: &dyn fmt::Display,
     ) -> ControlFlow<Self::BreakTy> {
         if self.check_def_id(def_id, kind, descr) {
-            ControlFlow::BREAK
+            ControlFlow::Break(())
         } else {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         }
     }
 }
diff --git a/compiler/rustc_resolve/src/check_unused.rs b/compiler/rustc_resolve/src/check_unused.rs
index 32fb5e18276..eae4c9992eb 100644
--- a/compiler/rustc_resolve/src/check_unused.rs
+++ b/compiler/rustc_resolve/src/check_unused.rs
@@ -28,9 +28,9 @@ use crate::module_to_string;
 use crate::Resolver;
 
 use rustc_ast as ast;
-use rustc_ast::node_id::NodeMap;
 use rustc_ast::visit::{self, Visitor};
-use rustc_data_structures::fx::FxHashSet;
+use rustc_data_structures::fx::FxIndexMap;
+use rustc_data_structures::unord::UnordSet;
 use rustc_errors::{pluralize, MultiSpan};
 use rustc_session::lint::builtin::{MACRO_USE_EXTERN_CRATE, UNUSED_IMPORTS};
 use rustc_session::lint::BuiltinLintDiagnostics;
@@ -40,7 +40,7 @@ struct UnusedImport<'a> {
     use_tree: &'a ast::UseTree,
     use_tree_id: ast::NodeId,
     item_span: Span,
-    unused: FxHashSet<ast::NodeId>,
+    unused: UnordSet<ast::NodeId>,
 }
 
 impl<'a> UnusedImport<'a> {
@@ -52,7 +52,7 @@ impl<'a> UnusedImport<'a> {
 struct UnusedImportCheckVisitor<'a, 'b> {
     r: &'a mut Resolver<'b>,
     /// All the (so far) unused imports, grouped path list
-    unused_imports: NodeMap<UnusedImport<'a>>,
+    unused_imports: FxIndexMap<ast::NodeId, UnusedImport<'a>>,
     base_use_tree: Option<&'a ast::UseTree>,
     base_id: ast::NodeId,
     item_span: Span,
@@ -89,7 +89,7 @@ impl<'a, 'b> UnusedImportCheckVisitor<'a, 'b> {
             use_tree,
             use_tree_id,
             item_span,
-            unused: FxHashSet::default(),
+            unused: Default::default(),
         })
     }
 }
diff --git a/compiler/rustc_resolve/src/diagnostics.rs b/compiler/rustc_resolve/src/diagnostics.rs
index fb2aebbd18a..36608615255 100644
--- a/compiler/rustc_resolve/src/diagnostics.rs
+++ b/compiler/rustc_resolve/src/diagnostics.rs
@@ -5,10 +5,10 @@ use rustc_ast::visit::{self, Visitor};
 use rustc_ast::{self as ast, Crate, ItemKind, ModKind, NodeId, Path, CRATE_NODE_ID};
 use rustc_ast_pretty::pprust;
 use rustc_data_structures::fx::FxHashSet;
-use rustc_errors::struct_span_err;
 use rustc_errors::{
     pluralize, Applicability, Diagnostic, DiagnosticBuilder, ErrorGuaranteed, MultiSpan,
 };
+use rustc_errors::{struct_span_err, SuggestionStyle};
 use rustc_feature::BUILTIN_ATTRIBUTES;
 use rustc_hir::def::Namespace::{self, *};
 use rustc_hir::def::{self, CtorKind, CtorOf, DefKind, NonMacroAttrKind, PerNS};
@@ -1033,7 +1033,7 @@ impl<'a> Resolver<'a> {
                     let root_module = this.resolve_crate_root(root_ident);
                     this.add_module_candidates(root_module, &mut suggestions, filter_fn, None);
                 }
-                Scope::Module(module) => {
+                Scope::Module(module, _) => {
                     this.add_module_candidates(module, &mut suggestions, filter_fn, None);
                 }
                 Scope::MacroUsePrelude => {
@@ -2125,9 +2125,15 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
 
                 let source_map = self.r.session.source_map();
 
+                // Make sure this is actually crate-relative.
+                let is_definitely_crate = import
+                    .module_path
+                    .first()
+                    .map_or(false, |f| f.ident.name != kw::SelfLower && f.ident.name != kw::Super);
+
                 // Add the import to the start, with a `{` if required.
                 let start_point = source_map.start_point(after_crate_name);
-                if let Ok(start_snippet) = source_map.span_to_snippet(start_point) {
+                if is_definitely_crate && let Ok(start_snippet) = source_map.span_to_snippet(start_point) {
                     corrections.push((
                         start_point,
                         if has_nested {
@@ -2139,11 +2145,17 @@ impl<'a, 'b> ImportResolver<'a, 'b> {
                             format!("{{{}, {}", import_snippet, start_snippet)
                         },
                     ));
-                }
 
-                // Add a `};` to the end if nested, matching the `{` added at the start.
-                if !has_nested {
-                    corrections.push((source_map.end_point(after_crate_name), "};".to_string()));
+                    // Add a `};` to the end if nested, matching the `{` added at the start.
+                    if !has_nested {
+                        corrections.push((source_map.end_point(after_crate_name), "};".to_string()));
+                    }
+                } else {
+                    // If the root import is module-relative, add the import separately
+                    corrections.push((
+                        import.use_span.shrink_to_lo(),
+                        format!("use {module_name}::{import_snippet};\n"),
+                    ));
                 }
             }
 
@@ -2418,7 +2430,7 @@ fn show_candidates(
         }
 
         if let Some(span) = use_placement_span {
-            let add_use = match mode {
+            let (add_use, trailing) = match mode {
                 DiagnosticMode::Pattern => {
                     err.span_suggestions(
                         span,
@@ -2428,21 +2440,23 @@ fn show_candidates(
                     );
                     return;
                 }
-                DiagnosticMode::Import => "",
-                DiagnosticMode::Normal => "use ",
+                DiagnosticMode::Import => ("", ""),
+                DiagnosticMode::Normal => ("use ", ";\n"),
             };
             for candidate in &mut accessible_path_strings {
                 // produce an additional newline to separate the new use statement
                 // from the directly following item.
-                let additional_newline = if let FoundUse::Yes = found_use { "" } else { "\n" };
-                candidate.0 = format!("{add_use}{}{append};\n{additional_newline}", &candidate.0);
+                let additional_newline = if let FoundUse::No = found_use && let DiagnosticMode::Normal = mode { "\n" } else { "" };
+                candidate.0 =
+                    format!("{add_use}{}{append}{trailing}{additional_newline}", &candidate.0);
             }
 
-            err.span_suggestions(
+            err.span_suggestions_with_style(
                 span,
                 &msg,
                 accessible_path_strings.into_iter().map(|a| a.0),
                 Applicability::MaybeIncorrect,
+                SuggestionStyle::ShowAlways,
             );
             if let [first, .., last] = &path[..] {
                 let sp = first.ident.span.until(last.ident.span);
@@ -2463,7 +2477,7 @@ fn show_candidates(
                 msg.push_str(&candidate.0);
             }
 
-            err.note(&msg);
+            err.help(&msg);
         }
     } else if !matches!(mode, DiagnosticMode::Import) {
         assert!(!inaccessible_path_strings.is_empty());
diff --git a/compiler/rustc_resolve/src/ident.rs b/compiler/rustc_resolve/src/ident.rs
index e41fe325b81..a84652a315d 100644
--- a/compiler/rustc_resolve/src/ident.rs
+++ b/compiler/rustc_resolve/src/ident.rs
@@ -1,9 +1,11 @@
-use rustc_ast as ast;
+use rustc_ast::{self as ast, NodeId};
 use rustc_feature::is_builtin_attr_name;
 use rustc_hir::def::{DefKind, Namespace, NonMacroAttrKind, PartialRes, PerNS};
 use rustc_hir::PrimTy;
 use rustc_middle::bug;
 use rustc_middle::ty;
+use rustc_session::lint::builtin::PROC_MACRO_DERIVE_RESOLUTION_FALLBACK;
+use rustc_session::lint::BuiltinLintDiagnostics;
 use rustc_span::def_id::LocalDefId;
 use rustc_span::edition::Edition;
 use rustc_span::hygiene::{ExpnId, ExpnKind, LocalExpnId, MacroKind, SyntaxContext};
@@ -99,7 +101,7 @@ impl<'a> Resolver<'a> {
         };
         let mut scope = match ns {
             _ if is_absolute_path => Scope::CrateRoot,
-            TypeNS | ValueNS => Scope::Module(module),
+            TypeNS | ValueNS => Scope::Module(module, None),
             MacroNS => Scope::DeriveHelpers(parent_scope.expansion),
         };
         let mut ctxt = ctxt.normalize_to_macros_2_0();
@@ -163,7 +165,7 @@ impl<'a> Resolver<'a> {
                     MacroRulesScope::Invocation(invoc_id) => {
                         Scope::MacroRules(self.invocation_parent_scopes[&invoc_id].macro_rules)
                     }
-                    MacroRulesScope::Empty => Scope::Module(module),
+                    MacroRulesScope::Empty => Scope::Module(module, None),
                 },
                 Scope::CrateRoot => match ns {
                     TypeNS => {
@@ -172,10 +174,16 @@ impl<'a> Resolver<'a> {
                     }
                     ValueNS | MacroNS => break,
                 },
-                Scope::Module(module) => {
+                Scope::Module(module, prev_lint_id) => {
                     use_prelude = !module.no_implicit_prelude;
-                    match self.hygienic_lexical_parent(module, &mut ctxt) {
-                        Some(parent_module) => Scope::Module(parent_module),
+                    let derive_fallback_lint_id = match scope_set {
+                        ScopeSet::Late(.., lint_id) => lint_id,
+                        _ => None,
+                    };
+                    match self.hygienic_lexical_parent(module, &mut ctxt, derive_fallback_lint_id) {
+                        Some((parent_module, lint_id)) => {
+                            Scope::Module(parent_module, lint_id.or(prev_lint_id))
+                        }
                         None => {
                             ctxt.adjust(ExpnId::root());
                             match ns {
@@ -207,13 +215,45 @@ impl<'a> Resolver<'a> {
         &mut self,
         module: Module<'a>,
         ctxt: &mut SyntaxContext,
-    ) -> Option<Module<'a>> {
+        derive_fallback_lint_id: Option<NodeId>,
+    ) -> Option<(Module<'a>, Option<NodeId>)> {
         if !module.expansion.outer_expn_is_descendant_of(*ctxt) {
-            return Some(self.expn_def_scope(ctxt.remove_mark()));
+            return Some((self.expn_def_scope(ctxt.remove_mark()), None));
         }
 
         if let ModuleKind::Block = module.kind {
-            return Some(module.parent.unwrap().nearest_item_scope());
+            return Some((module.parent.unwrap().nearest_item_scope(), None));
+        }
+
+        // We need to support the next case under a deprecation warning
+        // ```
+        // struct MyStruct;
+        // ---- begin: this comes from a proc macro derive
+        // mod implementation_details {
+        //     // Note that `MyStruct` is not in scope here.
+        //     impl SomeTrait for MyStruct { ... }
+        // }
+        // ---- end
+        // ```
+        // So we have to fall back to the module's parent during lexical resolution in this case.
+        if derive_fallback_lint_id.is_some() {
+            if let Some(parent) = module.parent {
+                // Inner module is inside the macro, parent module is outside of the macro.
+                if module.expansion != parent.expansion
+                    && module.expansion.is_descendant_of(parent.expansion)
+                {
+                    // The macro is a proc macro derive
+                    if let Some(def_id) = module.expansion.expn_data().macro_def_id {
+                        let ext = self.get_macro_by_def_id(def_id).ext;
+                        if ext.builtin_name.is_none()
+                            && ext.macro_kind() == MacroKind::Derive
+                            && parent.expansion.outer_expn_is_descendant_of(*ctxt)
+                        {
+                            return Some((parent, derive_fallback_lint_id));
+                        }
+                    }
+                }
+            }
         }
 
         None
@@ -470,7 +510,7 @@ impl<'a> Resolver<'a> {
                             Err((Determinacy::Determined, _)) => Err(Determinacy::Determined),
                         }
                     }
-                    Scope::Module(module) => {
+                    Scope::Module(module, derive_fallback_lint_id) => {
                         let adjusted_parent_scope = &ParentScope { module, ..*parent_scope };
                         let binding = this.resolve_ident_in_module_unadjusted_ext(
                             ModuleOrUniformRoot::Module(module),
@@ -483,6 +523,21 @@ impl<'a> Resolver<'a> {
                         );
                         match binding {
                             Ok(binding) => {
+                                if let Some(lint_id) = derive_fallback_lint_id {
+                                    this.lint_buffer.buffer_lint_with_diagnostic(
+                                        PROC_MACRO_DERIVE_RESOLUTION_FALLBACK,
+                                        lint_id,
+                                        orig_ident.span,
+                                        &format!(
+                                            "cannot find {} `{}` in this scope",
+                                            ns.descr(),
+                                            ident
+                                        ),
+                                        BuiltinLintDiagnostics::ProcMacroDeriveResolutionFallback(
+                                            orig_ident.span,
+                                        ),
+                                    );
+                                }
                                 let misc_flags = if ptr::eq(module, this.graph_root) {
                                     Flags::MISC_SUGGEST_CRATE
                                 } else if module.is_normal() {
diff --git a/compiler/rustc_resolve/src/late.rs b/compiler/rustc_resolve/src/late.rs
index d6491b8b014..83932c089b3 100644
--- a/compiler/rustc_resolve/src/late.rs
+++ b/compiler/rustc_resolve/src/late.rs
@@ -3373,7 +3373,7 @@ impl<'a: 'ast, 'b, 'ast> LateResolutionVisitor<'a, 'b, 'ast> {
                         sugg.to_string(),
                         Applicability::MaybeIncorrect,
                     ))
-                } else if res.is_none() {
+                } else if res.is_none() && matches!(source, PathSource::Type) {
                     this.report_missing_type_error(path)
                 } else {
                     None
diff --git a/compiler/rustc_resolve/src/late/diagnostics.rs b/compiler/rustc_resolve/src/late/diagnostics.rs
index d92b046d0b9..6d448433ee6 100644
--- a/compiler/rustc_resolve/src/late/diagnostics.rs
+++ b/compiler/rustc_resolve/src/late/diagnostics.rs
@@ -2188,15 +2188,31 @@ impl<'a: 'ast, 'ast> LateResolutionVisitor<'a, '_, 'ast> {
             let deletion_span = || {
                 if params.len() == 1 {
                     // if sole lifetime, remove the entire `<>` brackets
-                    generics_span
+                    Some(generics_span)
                 } else if param_index == 0 {
                     // if removing within `<>` brackets, we also want to
                     // delete a leading or trailing comma as appropriate
-                    param.span().to(params[param_index + 1].span().shrink_to_lo())
+                    match (
+                        param.span().find_ancestor_inside(generics_span),
+                        params[param_index + 1].span().find_ancestor_inside(generics_span),
+                    ) {
+                        (Some(param_span), Some(next_param_span)) => {
+                            Some(param_span.to(next_param_span.shrink_to_lo()))
+                        }
+                        _ => None,
+                    }
                 } else {
                     // if removing within `<>` brackets, we also want to
                     // delete a leading or trailing comma as appropriate
-                    params[param_index - 1].span().shrink_to_hi().to(param.span())
+                    match (
+                        param.span().find_ancestor_inside(generics_span),
+                        params[param_index - 1].span().find_ancestor_inside(generics_span),
+                    ) {
+                        (Some(param_span), Some(prev_param_span)) => {
+                            Some(prev_param_span.shrink_to_hi().to(param_span))
+                        }
+                        _ => None,
+                    }
                 }
             };
             match use_set {
diff --git a/compiler/rustc_resolve/src/lib.rs b/compiler/rustc_resolve/src/lib.rs
index f950e4a9bee..1b181b71400 100644
--- a/compiler/rustc_resolve/src/lib.rs
+++ b/compiler/rustc_resolve/src/lib.rs
@@ -105,7 +105,9 @@ enum Scope<'a> {
     DeriveHelpersCompat,
     MacroRules(MacroRulesScopeRef<'a>),
     CrateRoot,
-    Module(Module<'a>),
+    // The node ID is for reporting the `PROC_MACRO_DERIVE_RESOLUTION_FALLBACK`
+    // lint if it should be reported.
+    Module(Module<'a>, Option<NodeId>),
     MacroUsePrelude,
     BuiltinAttrs,
     ExternPrelude,
@@ -1591,7 +1593,7 @@ impl<'a> Resolver<'a> {
 
         self.visit_scopes(ScopeSet::All(TypeNS, false), parent_scope, ctxt, |this, scope, _, _| {
             match scope {
-                Scope::Module(module) => {
+                Scope::Module(module, _) => {
                     this.traits_in_module(module, assoc_item, &mut found_traits);
                 }
                 Scope::StdLibPrelude => {
diff --git a/compiler/rustc_save_analysis/src/dump_visitor.rs b/compiler/rustc_save_analysis/src/dump_visitor.rs
index 9ae07cb005b..a5f09de1c40 100644
--- a/compiler/rustc_save_analysis/src/dump_visitor.rs
+++ b/compiler/rustc_save_analysis/src/dump_visitor.rs
@@ -112,9 +112,7 @@ impl<'tcx> DumpVisitor<'tcx> {
     }
 
     pub fn dump_crate_info(&mut self, name: Symbol) {
-        let source_file = self.tcx.sess.local_crate_source_file.as_ref();
-        let crate_root = source_file.map(|source_file| {
-            let source_file = Path::new(source_file);
+        let crate_root = self.tcx.sess.local_crate_source_file().map(|source_file| {
             match source_file.file_name() {
                 Some(_) => source_file.parent().unwrap().display(),
                 None => source_file.display(),
@@ -157,10 +155,14 @@ impl<'tcx> DumpVisitor<'tcx> {
                 .enumerate()
                 .filter(|(i, _)| !remap_arg_indices.contains(i))
                 .map(|(_, arg)| match input {
-                    Input::File(ref path) if path == Path::new(&arg) => {
-                        let mapped = &self.tcx.sess.local_crate_source_file;
-                        mapped.as_ref().unwrap().to_string_lossy().into()
-                    }
+                    Input::File(ref path) if path == Path::new(&arg) => self
+                        .tcx
+                        .sess
+                        .local_crate_source_file()
+                        .as_ref()
+                        .unwrap()
+                        .to_string_lossy()
+                        .into(),
                     _ => arg,
                 });
 
diff --git a/compiler/rustc_save_analysis/src/span_utils.rs b/compiler/rustc_save_analysis/src/span_utils.rs
index 8d6758f40f9..e65d57bb3db 100644
--- a/compiler/rustc_save_analysis/src/span_utils.rs
+++ b/compiler/rustc_save_analysis/src/span_utils.rs
@@ -18,13 +18,7 @@ impl<'a> SpanUtils<'a> {
         match &file.name {
             FileName::Real(RealFileName::LocalPath(path)) => {
                 if path.is_absolute() {
-                    self.sess
-                        .source_map()
-                        .path_mapping()
-                        .map_prefix(path.into())
-                        .0
-                        .display()
-                        .to_string()
+                    self.sess.source_map().path_mapping().map_prefix(path).0.display().to_string()
                 } else {
                     self.sess
                         .opts
diff --git a/compiler/rustc_session/src/config.rs b/compiler/rustc_session/src/config.rs
index dcc2d9db614..586454f7657 100644
--- a/compiler/rustc_session/src/config.rs
+++ b/compiler/rustc_session/src/config.rs
@@ -591,6 +591,24 @@ impl Input {
             Input::Str { ref name, .. } => name.clone(),
         }
     }
+
+    pub fn opt_path(&self) -> Option<&Path> {
+        match self {
+            Input::File(file) => Some(file),
+            Input::Str { name, .. } => match name {
+                FileName::Real(real) => real.local_path(),
+                FileName::QuoteExpansion(_) => None,
+                FileName::Anon(_) => None,
+                FileName::MacroExpansion(_) => None,
+                FileName::ProcMacroSourceCode(_) => None,
+                FileName::CfgSpec(_) => None,
+                FileName::CliCrateAttr(_) => None,
+                FileName::Custom(_) => None,
+                FileName::DocTest(path, _) => Some(path),
+                FileName::InlineAsm(_) => None,
+            },
+        }
+    }
 }
 
 #[derive(Clone, Hash, Debug, HashStable_Generic)]
@@ -2459,6 +2477,11 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
 
     let pretty = parse_pretty(&unstable_opts, error_format);
 
+    // query-dep-graph is required if dump-dep-graph is given #106736
+    if unstable_opts.dump_dep_graph && !unstable_opts.query_dep_graph {
+        early_error(error_format, "can't dump dependency graph without `-Z query-dep-graph`");
+    }
+
     // Try to find a directory containing the Rust `src`, for more details see
     // the doc comment on the `real_rust_source_base_dir` field.
     let tmp_buf;
@@ -2491,12 +2514,12 @@ pub fn build_session_options(matches: &getopts::Matches) -> Options {
         early_error(error_format, &format!("Current directory is invalid: {e}"));
     });
 
-    let (path, remapped) =
-        FilePathMapping::new(remap_path_prefix.clone()).map_prefix(working_dir.clone());
+    let remap = FilePathMapping::new(remap_path_prefix.clone());
+    let (path, remapped) = remap.map_prefix(&working_dir);
     let working_dir = if remapped {
-        RealFileName::Remapped { local_path: Some(working_dir), virtual_name: path }
+        RealFileName::Remapped { virtual_name: path.into_owned(), local_path: Some(working_dir) }
     } else {
-        RealFileName::LocalPath(path)
+        RealFileName::LocalPath(path.into_owned())
     };
 
     Options {
diff --git a/compiler/rustc_session/src/output.rs b/compiler/rustc_session/src/output.rs
index cf45d6f1aa5..c3f0c4b58f5 100644
--- a/compiler/rustc_session/src/output.rs
+++ b/compiler/rustc_session/src/output.rs
@@ -45,7 +45,7 @@ fn is_writeable(p: &Path) -> bool {
     }
 }
 
-pub fn find_crate_name(sess: &Session, attrs: &[ast::Attribute], input: &Input) -> Symbol {
+pub fn find_crate_name(sess: &Session, attrs: &[ast::Attribute]) -> Symbol {
     let validate = |s: Symbol, span: Option<Span>| {
         validate_crate_name(sess, s, span);
         s
@@ -71,7 +71,7 @@ pub fn find_crate_name(sess: &Session, attrs: &[ast::Attribute], input: &Input)
     if let Some((attr, s)) = attr_crate_name {
         return validate(s, Some(attr.span));
     }
-    if let Input::File(ref path) = *input {
+    if let Input::File(ref path) = sess.io.input {
         if let Some(s) = path.file_stem().and_then(|s| s.to_str()) {
             if s.starts_with('-') {
                 sess.emit_err(CrateNameInvalid { s });
diff --git a/compiler/rustc_session/src/session.rs b/compiler/rustc_session/src/session.rs
index 8d92954ec94..95f199de6ff 100644
--- a/compiler/rustc_session/src/session.rs
+++ b/compiler/rustc_session/src/session.rs
@@ -1,6 +1,7 @@
 use crate::cgu_reuse_tracker::CguReuseTracker;
 use crate::code_stats::CodeStats;
 pub use crate::code_stats::{DataTypeKind, FieldInfo, SizeKind, VariantInfo};
+use crate::config::Input;
 use crate::config::{self, CrateType, InstrumentCoverage, OptLevel, OutputType, SwitchWithOptPath};
 use crate::errors::{
     BranchProtectionRequiresAArch64, CannotEnableCrtStaticLinux, CannotMixAndMatchSanitizers,
@@ -137,6 +138,13 @@ pub struct Limits {
     pub const_eval_limit: Limit,
 }
 
+pub struct CompilerIO {
+    pub input: Input,
+    pub output_dir: Option<PathBuf>,
+    pub output_file: Option<PathBuf>,
+    pub temps_dir: Option<PathBuf>,
+}
+
 /// Represents the data associated with a compilation
 /// session for a single crate.
 pub struct Session {
@@ -147,9 +155,8 @@ pub struct Session {
     pub target_tlib_path: Lrc<SearchPath>,
     pub parse_sess: ParseSess,
     pub sysroot: PathBuf,
-    /// The name of the root source file of the crate, in the local file system.
-    /// `None` means that there is no source file.
-    pub local_crate_source_file: Option<PathBuf>,
+    /// Input, input file path and output file path to this compilation process.
+    pub io: CompilerIO,
 
     crate_types: OnceCell<Vec<CrateType>>,
     /// The `stable_crate_id` is constructed out of the crate name and all the
@@ -228,6 +235,11 @@ impl Session {
         self.miri_unleashed_features.lock().push((span, feature_gate));
     }
 
+    pub fn local_crate_source_file(&self) -> Option<PathBuf> {
+        let path = self.io.input.opt_path()?;
+        Some(self.opts.file_path_mapping().map_prefix(path).0.into_owned())
+    }
+
     fn check_miri_unleashed_features(&self) {
         let unleashed_features = self.miri_unleashed_features.lock();
         if !unleashed_features.is_empty() {
@@ -1298,7 +1310,7 @@ fn default_emitter(
 #[allow(rustc::bad_opt_access)]
 pub fn build_session(
     sopts: config::Options,
-    local_crate_source_file: Option<PathBuf>,
+    io: CompilerIO,
     bundle: Option<Lrc<rustc_errors::FluentBundle>>,
     registry: rustc_errors::registry::Registry,
     driver_lint_caps: FxHashMap<lint::LintId, lint::Level>,
@@ -1391,11 +1403,6 @@ pub fn build_session(
         Lrc::new(SearchPath::from_sysroot_and_triple(&sysroot, target_triple))
     };
 
-    let file_path_mapping = sopts.file_path_mapping();
-
-    let local_crate_source_file =
-        local_crate_source_file.map(|path| file_path_mapping.map_prefix(path).0);
-
     let optimization_fuel = Lock::new(OptimizationFuel {
         remaining: sopts.unstable_opts.fuel.as_ref().map_or(0, |&(_, i)| i),
         out_of_fuel: false,
@@ -1427,7 +1434,7 @@ pub fn build_session(
         target_tlib_path,
         parse_sess,
         sysroot,
-        local_crate_source_file,
+        io,
         crate_types: OnceCell::new(),
         stable_crate_id: OnceCell::new(),
         features: OnceCell::new(),
diff --git a/compiler/rustc_span/src/source_map.rs b/compiler/rustc_span/src/source_map.rs
index fa09b4faa44..2e339a9d2d2 100644
--- a/compiler/rustc_span/src/source_map.rs
+++ b/compiler/rustc_span/src/source_map.rs
@@ -17,7 +17,7 @@ use rustc_data_structures::stable_hasher::StableHasher;
 use rustc_data_structures::sync::{AtomicU32, Lrc, MappedReadGuard, ReadGuard, RwLock};
 use std::cmp;
 use std::hash::Hash;
-use std::path::{Path, PathBuf};
+use std::path::{self, Path, PathBuf};
 use std::sync::atomic::Ordering;
 
 use std::fs;
@@ -1071,12 +1071,24 @@ impl SourceMap {
 
     pub fn ensure_source_file_source_present(&self, source_file: Lrc<SourceFile>) -> bool {
         source_file.add_external_src(|| {
-            match source_file.name {
-                FileName::Real(ref name) if let Some(local_path) = name.local_path() => {
-                    self.file_loader.read_file(local_path).ok()
+            let FileName::Real(ref name) = source_file.name else {
+                return None;
+            };
+
+            let local_path: Cow<'_, Path> = match name {
+                RealFileName::LocalPath(local_path) => local_path.into(),
+                RealFileName::Remapped { local_path: Some(local_path), .. } => local_path.into(),
+                RealFileName::Remapped { local_path: None, virtual_name } => {
+                    // The compiler produces better error messages if the sources of dependencies
+                    // are available. Attempt to undo any path mapping so we can find remapped
+                    // dependencies.
+                    // We can only use the heuristic because `add_external_src` checks the file
+                    // content hash.
+                    self.path_mapping.reverse_map_prefix_heuristically(virtual_name)?.into()
                 }
-                _ => None,
-            }
+            };
+
+            self.file_loader.read_file(&local_path).ok()
         })
     }
 
@@ -1138,7 +1150,8 @@ impl FilePathMapping {
     /// Applies any path prefix substitution as defined by the mapping.
     /// The return value is the remapped path and a boolean indicating whether
     /// the path was affected by the mapping.
-    pub fn map_prefix(&self, path: PathBuf) -> (PathBuf, bool) {
+    pub fn map_prefix<'a>(&'a self, path: impl Into<Cow<'a, Path>>) -> (Cow<'a, Path>, bool) {
+        let path = path.into();
         if path.as_os_str().is_empty() {
             // Exit early if the path is empty and therefore there's nothing to remap.
             // This is mostly to reduce spam for `RUSTC_LOG=[remap_path_prefix]`.
@@ -1148,7 +1161,10 @@ impl FilePathMapping {
         return remap_path_prefix(&self.mapping, path);
 
         #[instrument(level = "debug", skip(mapping), ret)]
-        fn remap_path_prefix(mapping: &[(PathBuf, PathBuf)], path: PathBuf) -> (PathBuf, bool) {
+        fn remap_path_prefix<'a>(
+            mapping: &'a [(PathBuf, PathBuf)],
+            path: Cow<'a, Path>,
+        ) -> (Cow<'a, Path>, bool) {
             // NOTE: We are iterating over the mapping entries from last to first
             //       because entries specified later on the command line should
             //       take precedence.
@@ -1163,9 +1179,9 @@ impl FilePathMapping {
                         // in remapped paths down the line.
                         // So, if we have an exact match, we just return that without a call
                         // to `Path::join()`.
-                        to.clone()
+                        to.into()
                     } else {
-                        to.join(rest)
+                        to.join(rest).into()
                     };
                     debug!("Match - remapped");
 
@@ -1183,11 +1199,11 @@ impl FilePathMapping {
     fn map_filename_prefix(&self, file: &FileName) -> (FileName, bool) {
         match file {
             FileName::Real(realfile) if let RealFileName::LocalPath(local_path) = realfile => {
-                let (mapped_path, mapped) = self.map_prefix(local_path.to_path_buf());
+                let (mapped_path, mapped) = self.map_prefix(local_path);
                 let realfile = if mapped {
                     RealFileName::Remapped {
                         local_path: Some(local_path.clone()),
-                        virtual_name: mapped_path,
+                        virtual_name: mapped_path.into_owned(),
                     }
                 } else {
                     realfile.clone()
@@ -1228,14 +1244,17 @@ impl FilePathMapping {
                 let (new_path, was_remapped) = self.map_prefix(unmapped_file_path);
                 if was_remapped {
                     // It was remapped, so don't modify further
-                    return RealFileName::Remapped { local_path: None, virtual_name: new_path };
+                    return RealFileName::Remapped {
+                        local_path: None,
+                        virtual_name: new_path.into_owned(),
+                    };
                 }
 
                 if new_path.is_absolute() {
                     // No remapping has applied to this path and it is absolute,
                     // so the working directory cannot influence it either, so
                     // we are done.
-                    return RealFileName::LocalPath(new_path);
+                    return RealFileName::LocalPath(new_path.into_owned());
                 }
 
                 debug_assert!(new_path.is_relative());
@@ -1253,12 +1272,12 @@ impl FilePathMapping {
                             RealFileName::Remapped {
                                 // Erase the actual path
                                 local_path: None,
-                                virtual_name: file_path_abs,
+                                virtual_name: file_path_abs.into_owned(),
                             }
                         } else {
                             // No kind of remapping applied to this path, so
                             // we leave it as it is.
-                            RealFileName::LocalPath(file_path_abs)
+                            RealFileName::LocalPath(file_path_abs.into_owned())
                         }
                     }
                     RealFileName::Remapped {
@@ -1277,4 +1296,43 @@ impl FilePathMapping {
             }
         }
     }
+
+    /// Attempts to (heuristically) reverse a prefix mapping.
+    ///
+    /// Returns [`Some`] if there is exactly one mapping where the "to" part is
+    /// a prefix of `path` and has at least one non-empty
+    /// [`Normal`](path::Component::Normal) component. The component
+    /// restriction exists to avoid reverse mapping overly generic paths like
+    /// `/` or `.`).
+    ///
+    /// This is a heuristic and not guaranteed to return the actual original
+    /// path! Do not rely on the result unless you have other means to verify
+    /// that the mapping is correct (e.g. by checking the file content hash).
+    #[instrument(level = "debug", skip(self), ret)]
+    fn reverse_map_prefix_heuristically(&self, path: &Path) -> Option<PathBuf> {
+        let mut found = None;
+
+        for (from, to) in self.mapping.iter() {
+            let has_normal_component = to.components().any(|c| match c {
+                path::Component::Normal(s) => !s.is_empty(),
+                _ => false,
+            });
+
+            if !has_normal_component {
+                continue;
+            }
+
+            let Ok(rest) = path.strip_prefix(to) else {
+                continue;
+            };
+
+            if found.is_some() {
+                return None;
+            }
+
+            found = Some(from.join(rest));
+        }
+
+        found
+    }
 }
diff --git a/compiler/rustc_span/src/source_map/tests.rs b/compiler/rustc_span/src/source_map/tests.rs
index 3cab59e8dbe..686b3b00d70 100644
--- a/compiler/rustc_span/src/source_map/tests.rs
+++ b/compiler/rustc_span/src/source_map/tests.rs
@@ -344,6 +344,10 @@ fn map_path_prefix(mapping: &FilePathMapping, p: &str) -> String {
     mapping.map_prefix(path(p)).0.to_string_lossy().to_string()
 }
 
+fn reverse_map_prefix(mapping: &FilePathMapping, p: &str) -> Option<String> {
+    mapping.reverse_map_prefix_heuristically(&path(p)).map(|q| q.to_string_lossy().to_string())
+}
+
 #[test]
 fn path_prefix_remapping() {
     // Relative to relative
@@ -387,7 +391,7 @@ fn path_prefix_remapping_expand_to_absolute() {
     let working_directory = path("/foo");
     let working_directory = RealFileName::Remapped {
         local_path: Some(working_directory.clone()),
-        virtual_name: mapping.map_prefix(working_directory).0,
+        virtual_name: mapping.map_prefix(working_directory).0.into_owned(),
     };
 
     assert_eq!(working_directory.remapped_path_if_available(), path("FOO"));
@@ -481,6 +485,45 @@ fn path_prefix_remapping_expand_to_absolute() {
 }
 
 #[test]
+fn path_prefix_remapping_reverse() {
+    // Ignores options without alphanumeric chars.
+    {
+        let mapping =
+            &FilePathMapping::new(vec![(path("abc"), path("/")), (path("def"), path("."))]);
+
+        assert_eq!(reverse_map_prefix(mapping, "/hello.rs"), None);
+        assert_eq!(reverse_map_prefix(mapping, "./hello.rs"), None);
+    }
+
+    // Returns `None` if multiple options match.
+    {
+        let mapping = &FilePathMapping::new(vec![
+            (path("abc"), path("/redacted")),
+            (path("def"), path("/redacted")),
+        ]);
+
+        assert_eq!(reverse_map_prefix(mapping, "/redacted/hello.rs"), None);
+    }
+
+    // Distinct reverse mappings.
+    {
+        let mapping = &FilePathMapping::new(vec![
+            (path("abc"), path("/redacted")),
+            (path("def/ghi"), path("/fake/dir")),
+        ]);
+
+        assert_eq!(
+            reverse_map_prefix(mapping, "/redacted/path/hello.rs"),
+            Some(path_str("abc/path/hello.rs"))
+        );
+        assert_eq!(
+            reverse_map_prefix(mapping, "/fake/dir/hello.rs"),
+            Some(path_str("def/ghi/hello.rs"))
+        );
+    }
+}
+
+#[test]
 fn test_next_point() {
     let sm = SourceMap::new(FilePathMapping::empty());
     sm.new_source_file(PathBuf::from("example.rs").into(), "a…b".to_string());
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index 706002f79b1..7597b8d126a 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -164,6 +164,7 @@ symbols! {
         Capture,
         Center,
         Clone,
+        Context,
         Continue,
         Copy,
         Count,
diff --git a/compiler/rustc_target/src/spec/s390x_unknown_linux_gnu.rs b/compiler/rustc_target/src/spec/s390x_unknown_linux_gnu.rs
index cda88de0ea4..f2c722b9a89 100644
--- a/compiler/rustc_target/src/spec/s390x_unknown_linux_gnu.rs
+++ b/compiler/rustc_target/src/spec/s390x_unknown_linux_gnu.rs
@@ -1,5 +1,5 @@
 use crate::abi::Endian;
-use crate::spec::{StackProbeType, Target};
+use crate::spec::{SanitizerSet, StackProbeType, Target};
 
 pub fn target() -> Target {
     let mut base = super::linux_gnu_base::opts();
@@ -13,6 +13,8 @@ pub fn target() -> Target {
     base.max_atomic_width = Some(64);
     base.min_global_align = Some(16);
     base.stack_probes = StackProbeType::Inline;
+    base.supported_sanitizers =
+        SanitizerSet::ADDRESS | SanitizerSet::LEAK | SanitizerSet::MEMORY | SanitizerSet::THREAD;
 
     Target {
         llvm_target: "s390x-unknown-linux-gnu".into(),
diff --git a/compiler/rustc_target/src/spec/s390x_unknown_linux_musl.rs b/compiler/rustc_target/src/spec/s390x_unknown_linux_musl.rs
index 91e63aee5e4..8fe9d023c52 100644
--- a/compiler/rustc_target/src/spec/s390x_unknown_linux_musl.rs
+++ b/compiler/rustc_target/src/spec/s390x_unknown_linux_musl.rs
@@ -1,5 +1,5 @@
 use crate::abi::Endian;
-use crate::spec::{StackProbeType, Target};
+use crate::spec::{SanitizerSet, StackProbeType, Target};
 
 pub fn target() -> Target {
     let mut base = super::linux_musl_base::opts();
@@ -14,6 +14,8 @@ pub fn target() -> Target {
     base.min_global_align = Some(16);
     base.static_position_independent_executables = true;
     base.stack_probes = StackProbeType::Inline;
+    base.supported_sanitizers =
+        SanitizerSet::ADDRESS | SanitizerSet::LEAK | SanitizerSet::MEMORY | SanitizerSet::THREAD;
 
     Target {
         llvm_target: "s390x-unknown-linux-musl".into(),
diff --git a/compiler/rustc_trait_selection/Cargo.toml b/compiler/rustc_trait_selection/Cargo.toml
index 67613e1a4eb..90d879976c2 100644
--- a/compiler/rustc_trait_selection/Cargo.toml
+++ b/compiler/rustc_trait_selection/Cargo.toml
@@ -19,6 +19,7 @@ rustc_infer = { path = "../rustc_infer" }
 rustc_lint_defs = { path = "../rustc_lint_defs" }
 rustc_macros = { path = "../rustc_macros" }
 rustc_query_system = { path = "../rustc_query_system" }
+rustc_serialize = { path = "../rustc_serialize" }
 rustc_session = { path = "../rustc_session" }
 rustc_span = { path = "../rustc_span" }
 rustc_target = { path = "../rustc_target" }
diff --git a/compiler/rustc_trait_selection/src/lib.rs b/compiler/rustc_trait_selection/src/lib.rs
index 081ac966c69..6fa09410363 100644
--- a/compiler/rustc_trait_selection/src/lib.rs
+++ b/compiler/rustc_trait_selection/src/lib.rs
@@ -21,6 +21,7 @@
 #![feature(never_type)]
 #![feature(result_option_inspect)]
 #![feature(type_alias_impl_trait)]
+#![feature(min_specialization)]
 #![recursion_limit = "512"] // For rustdoc
 
 #[macro_use]
diff --git a/compiler/rustc_trait_selection/src/solve/assembly.rs b/compiler/rustc_trait_selection/src/solve/assembly.rs
index ba68da0686f..cdb72d49834 100644
--- a/compiler/rustc_trait_selection/src/solve/assembly.rs
+++ b/compiler/rustc_trait_selection/src/solve/assembly.rs
@@ -1,38 +1,85 @@
 //! Code shared by trait and projection goals for candidate assembly.
 
 use super::infcx_ext::InferCtxtExt;
-use super::{
-    instantiate_canonical_query_response, CanonicalGoal, CanonicalResponse, Certainty, EvalCtxt,
-    Goal,
-};
+use super::{CanonicalResponse, Certainty, EvalCtxt, Goal, QueryResult};
 use rustc_hir::def_id::DefId;
-use rustc_infer::infer::TyCtxtInferExt;
-use rustc_infer::infer::{
-    canonical::{CanonicalVarValues, OriginalQueryValues},
-    InferCtxt,
-};
 use rustc_infer::traits::query::NoSolution;
+use rustc_infer::traits::util::elaborate_predicates;
 use rustc_middle::ty::TypeFoldable;
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_span::DUMMY_SP;
 use std::fmt::Debug;
 
 /// A candidate is a possible way to prove a goal.
 ///
 /// It consists of both the `source`, which describes how that goal would be proven,
 /// and the `result` when using the given `source`.
-///
-/// For the list of possible candidates, please look at the documentation of
-/// [super::trait_goals::CandidateSource] and [super::project_goals::CandidateSource].
 #[derive(Debug, Clone)]
-pub(super) struct Candidate<'tcx, G: GoalKind<'tcx>> {
-    pub(super) source: G::CandidateSource,
+pub(super) struct Candidate<'tcx> {
+    pub(super) source: CandidateSource,
     pub(super) result: CanonicalResponse<'tcx>,
 }
 
-pub(super) trait GoalKind<'tcx>: TypeFoldable<'tcx> + Copy {
-    type CandidateSource: Debug + Copy;
+/// Possible ways the given goal can be proven.
+#[derive(Debug, Clone, Copy)]
+pub(super) enum CandidateSource {
+    /// A user written impl.
+    ///
+    /// ## Examples
+    ///
+    /// ```rust
+    /// fn main() {
+    ///     let x: Vec<u32> = Vec::new();
+    ///     // This uses the impl from the standard library to prove `Vec<T>: Clone`.
+    ///     let y = x.clone();
+    /// }
+    /// ```
+    Impl(DefId),
+    /// A builtin impl generated by the compiler. When adding a new special
+    /// trait, try to use actual impls whenever possible. Builtin impls should
+    /// only be used in cases where the impl cannot be manually be written.
+    ///
+    /// Notable examples are auto traits, `Sized`, and `DiscriminantKind`.
+    /// For a list of all traits with builtin impls, check out the
+    /// [`EvalCtxt::assemble_builtin_impl_candidates`] method. Not
+    BuiltinImpl,
+    /// An assumption from the environment.
+    ///
+    /// More precicely we've used the `n-th` assumption in the `param_env`.
+    ///
+    /// ## Examples
+    ///
+    /// ```rust
+    /// fn is_clone<T: Clone>(x: T) -> (T, T) {
+    ///     // This uses the assumption `T: Clone` from the `where`-bounds
+    ///     // to prove `T: Clone`.
+    ///     (x.clone(), x)
+    /// }
+    /// ```
+    ParamEnv(usize),
+    /// If the self type is an alias type, e.g. an opaque type or a projection,
+    /// we know the bounds on that alias to hold even without knowing its concrete
+    /// underlying type.
+    ///
+    /// More precisely this candidate is using the `n-th` bound in the `item_bounds` of
+    /// the self type.
+    ///
+    /// ## Examples
+    ///
+    /// ```rust
+    /// trait Trait {
+    ///     type Assoc: Clone;
+    /// }
+    ///
+    /// fn foo<T: Trait>(x: <T as Trait>::Assoc) {
+    ///     // We prove `<T as Trait>::Assoc` by looking at the bounds on `Assoc` in
+    ///     // in the trait definition.
+    ///     let _y = x.clone();
+    /// }
+    /// ```
+    AliasBound(usize),
+}
 
+pub(super) trait GoalKind<'tcx>: TypeFoldable<'tcx> + Copy + Eq {
     fn self_ty(self) -> Ty<'tcx>;
 
     fn with_self_ty(self, tcx: TyCtxt<'tcx>, self_ty: Ty<'tcx>) -> Self;
@@ -40,47 +87,86 @@ pub(super) trait GoalKind<'tcx>: TypeFoldable<'tcx> + Copy {
     fn trait_def_id(self, tcx: TyCtxt<'tcx>) -> DefId;
 
     fn consider_impl_candidate(
-        acx: &mut AssemblyCtxt<'_, 'tcx, Self>,
+        ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, Self>,
         impl_def_id: DefId,
-    );
-}
+    ) -> QueryResult<'tcx>;
 
-/// An abstraction which correctly deals with the canonical results for candidates.
-///
-/// It also deduplicates the behavior between trait and projection predicates.
-pub(super) struct AssemblyCtxt<'a, 'tcx, G: GoalKind<'tcx>> {
-    pub(super) cx: &'a mut EvalCtxt<'tcx>,
-    pub(super) infcx: &'a InferCtxt<'tcx>,
-    var_values: CanonicalVarValues<'tcx>,
-    candidates: Vec<Candidate<'tcx, G>>,
-}
+    fn consider_assumption(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+        assumption: ty::Predicate<'tcx>,
+    ) -> QueryResult<'tcx>;
+
+    fn consider_auto_trait_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx>;
 
-impl<'a, 'tcx, G: GoalKind<'tcx>> AssemblyCtxt<'a, 'tcx, G> {
-    pub(super) fn assemble_and_evaluate_candidates(
-        cx: &'a mut EvalCtxt<'tcx>,
-        goal: CanonicalGoal<'tcx, G>,
-    ) -> Vec<Candidate<'tcx, G>> {
-        let (ref infcx, goal, var_values) =
-            cx.tcx.infer_ctxt().build_with_canonical(DUMMY_SP, &goal);
-        let mut acx = AssemblyCtxt { cx, infcx, var_values, candidates: Vec::new() };
+    fn consider_trait_alias_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx>;
 
-        acx.assemble_candidates_after_normalizing_self_ty(goal);
+    fn consider_builtin_sized_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx>;
 
-        acx.assemble_impl_candidates(goal);
+    fn consider_builtin_copy_clone_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx>;
 
-        acx.candidates
-    }
+    fn consider_builtin_pointer_sized_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx>;
+
+    fn consider_builtin_fn_trait_candidates(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+        kind: ty::ClosureKind,
+    ) -> QueryResult<'tcx>;
+
+    fn consider_builtin_tuple_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx>;
+}
 
-    pub(super) fn try_insert_candidate(
+impl<'tcx> EvalCtxt<'_, 'tcx> {
+    pub(super) fn assemble_and_evaluate_candidates<G: GoalKind<'tcx>>(
         &mut self,
-        source: G::CandidateSource,
-        certainty: Certainty,
-    ) {
-        match self.infcx.make_canonical_response(self.var_values.clone(), certainty) {
-            Ok(result) => self.candidates.push(Candidate { source, result }),
-            Err(NoSolution) => debug!(?source, ?certainty, "failed leakcheck"),
+        goal: Goal<'tcx, G>,
+    ) -> Vec<Candidate<'tcx>> {
+        debug_assert_eq!(goal, self.infcx.resolve_vars_if_possible(goal));
+
+        // HACK: `_: Trait` is ambiguous, because it may be satisfied via a builtin rule,
+        // object bound, alias bound, etc. We are unable to determine this until we can at
+        // least structually resolve the type one layer.
+        if goal.predicate.self_ty().is_ty_var() {
+            return vec![Candidate {
+                source: CandidateSource::BuiltinImpl,
+                result: self.make_canonical_response(Certainty::AMBIGUOUS).unwrap(),
+            }];
         }
+
+        let mut candidates = Vec::new();
+
+        self.assemble_candidates_after_normalizing_self_ty(goal, &mut candidates);
+
+        self.assemble_impl_candidates(goal, &mut candidates);
+
+        self.assemble_builtin_impl_candidates(goal, &mut candidates);
+
+        self.assemble_param_env_candidates(goal, &mut candidates);
+
+        self.assemble_alias_bound_candidates(goal, &mut candidates);
+
+        self.assemble_object_bound_candidates(goal, &mut candidates);
+
+        candidates
     }
 
     /// If the self type of a goal is a projection, computing the relevant candidates is difficult.
@@ -88,8 +174,12 @@ impl<'a, 'tcx, G: GoalKind<'tcx>> AssemblyCtxt<'a, 'tcx, G> {
     /// To deal with this, we first try to normalize the self type and add the candidates for the normalized
     /// self type to the list of candidates in case that succeeds. Note that we can't just eagerly return in
     /// this case as projections as self types add `
-    fn assemble_candidates_after_normalizing_self_ty(&mut self, goal: Goal<'tcx, G>) {
-        let tcx = self.cx.tcx;
+    fn assemble_candidates_after_normalizing_self_ty<G: GoalKind<'tcx>>(
+        &mut self,
+        goal: Goal<'tcx, G>,
+        candidates: &mut Vec<Candidate<'tcx>>,
+    ) {
+        let tcx = self.tcx();
         // FIXME: We also have to normalize opaque types, not sure where to best fit that in.
         let &ty::Alias(ty::Projection, projection_ty) = goal.predicate.self_ty().kind() else {
             return
@@ -103,45 +193,193 @@ impl<'a, 'tcx, G: GoalKind<'tcx>> AssemblyCtxt<'a, 'tcx, G> {
                     term: normalized_ty.into(),
                 }),
             );
-            let normalization_certainty =
-                match self.cx.evaluate_goal(&self.infcx, normalizes_to_goal) {
-                    Ok((_, certainty)) => certainty,
-                    Err(NoSolution) => return,
-                };
+            let normalization_certainty = match self.evaluate_goal(normalizes_to_goal) {
+                Ok((_, certainty)) => certainty,
+                Err(NoSolution) => return,
+            };
+            let normalized_ty = self.infcx.resolve_vars_if_possible(normalized_ty);
 
             // NOTE: Alternatively we could call `evaluate_goal` here and only have a `Normalized` candidate.
-            // This doesn't work as long as we use `CandidateSource` in both winnowing and to resolve associated items.
+            // This doesn't work as long as we use `CandidateSource` in winnowing.
             let goal = goal.with(tcx, goal.predicate.with_self_ty(tcx, normalized_ty));
-            let mut orig_values = OriginalQueryValues::default();
-            let goal = self.infcx.canonicalize_query(goal, &mut orig_values);
-            let normalized_candidates =
-                AssemblyCtxt::assemble_and_evaluate_candidates(self.cx, goal);
-
-            // Map each candidate from being canonical wrt the current inference context to being
-            // canonical wrt the caller.
-            for Candidate { source, result } in normalized_candidates {
-                self.infcx.probe(|_| {
-                    let candidate_certainty =
-                        instantiate_canonical_query_response(&self.infcx, &orig_values, result);
-
-                    // FIXME: This is a bit scary if the `normalizes_to_goal` overflows.
-                    //
-                    // If we have an ambiguous candidate it hides that normalization
-                    // caused an overflow which may cause issues.
-                    self.try_insert_candidate(
-                        source,
-                        normalization_certainty.unify_and(candidate_certainty),
-                    )
-                })
+            // FIXME: This is broken if we care about the `usize` of `AliasBound` because the self type
+            // could be normalized to yet another projection with different item bounds.
+            let normalized_candidates = self.assemble_and_evaluate_candidates(goal);
+            for mut normalized_candidate in normalized_candidates {
+                normalized_candidate.result =
+                    normalized_candidate.result.unchecked_map(|mut response| {
+                        // FIXME: This currently hides overflow in the normalization step of the self type
+                        // which is probably wrong. Maybe `unify_and` should actually keep overflow as
+                        // we treat it as non-fatal anyways.
+                        response.certainty = response.certainty.unify_and(normalization_certainty);
+                        response
+                    });
+                candidates.push(normalized_candidate);
             }
         })
     }
 
-    fn assemble_impl_candidates(&mut self, goal: Goal<'tcx, G>) {
-        self.cx.tcx.for_each_relevant_impl(
-            goal.predicate.trait_def_id(self.cx.tcx),
+    fn assemble_impl_candidates<G: GoalKind<'tcx>>(
+        &mut self,
+        goal: Goal<'tcx, G>,
+        candidates: &mut Vec<Candidate<'tcx>>,
+    ) {
+        let tcx = self.tcx();
+        tcx.for_each_relevant_impl(
+            goal.predicate.trait_def_id(tcx),
             goal.predicate.self_ty(),
-            |impl_def_id| G::consider_impl_candidate(self, goal, impl_def_id),
+            |impl_def_id| match G::consider_impl_candidate(self, goal, impl_def_id) {
+                Ok(result) => candidates
+                    .push(Candidate { source: CandidateSource::Impl(impl_def_id), result }),
+                Err(NoSolution) => (),
+            },
         );
     }
+
+    fn assemble_builtin_impl_candidates<G: GoalKind<'tcx>>(
+        &mut self,
+        goal: Goal<'tcx, G>,
+        candidates: &mut Vec<Candidate<'tcx>>,
+    ) {
+        let lang_items = self.tcx().lang_items();
+        let trait_def_id = goal.predicate.trait_def_id(self.tcx());
+        let result = if self.tcx().trait_is_auto(trait_def_id) {
+            G::consider_auto_trait_candidate(self, goal)
+        } else if self.tcx().trait_is_alias(trait_def_id) {
+            G::consider_trait_alias_candidate(self, goal)
+        } else if lang_items.sized_trait() == Some(trait_def_id) {
+            G::consider_builtin_sized_candidate(self, goal)
+        } else if lang_items.copy_trait() == Some(trait_def_id)
+            || lang_items.clone_trait() == Some(trait_def_id)
+        {
+            G::consider_builtin_copy_clone_candidate(self, goal)
+        } else if lang_items.pointer_sized() == Some(trait_def_id) {
+            G::consider_builtin_pointer_sized_candidate(self, goal)
+        } else if let Some(kind) = self.tcx().fn_trait_kind_from_def_id(trait_def_id) {
+            G::consider_builtin_fn_trait_candidates(self, goal, kind)
+        } else if lang_items.tuple_trait() == Some(trait_def_id) {
+            G::consider_builtin_tuple_candidate(self, goal)
+        } else {
+            Err(NoSolution)
+        };
+
+        match result {
+            Ok(result) => {
+                candidates.push(Candidate { source: CandidateSource::BuiltinImpl, result })
+            }
+            Err(NoSolution) => (),
+        }
+    }
+
+    fn assemble_param_env_candidates<G: GoalKind<'tcx>>(
+        &mut self,
+        goal: Goal<'tcx, G>,
+        candidates: &mut Vec<Candidate<'tcx>>,
+    ) {
+        for (i, assumption) in goal.param_env.caller_bounds().iter().enumerate() {
+            match G::consider_assumption(self, goal, assumption) {
+                Ok(result) => {
+                    candidates.push(Candidate { source: CandidateSource::ParamEnv(i), result })
+                }
+                Err(NoSolution) => (),
+            }
+        }
+    }
+
+    fn assemble_alias_bound_candidates<G: GoalKind<'tcx>>(
+        &mut self,
+        goal: Goal<'tcx, G>,
+        candidates: &mut Vec<Candidate<'tcx>>,
+    ) {
+        let alias_ty = match goal.predicate.self_ty().kind() {
+            ty::Bool
+            | ty::Char
+            | ty::Int(_)
+            | ty::Uint(_)
+            | ty::Float(_)
+            | ty::Adt(_, _)
+            | ty::Foreign(_)
+            | ty::Str
+            | ty::Array(_, _)
+            | ty::Slice(_)
+            | ty::RawPtr(_)
+            | ty::Ref(_, _, _)
+            | ty::FnDef(_, _)
+            | ty::FnPtr(_)
+            | ty::Dynamic(..)
+            | ty::Closure(..)
+            | ty::Generator(..)
+            | ty::GeneratorWitness(_)
+            | ty::Never
+            | ty::Tuple(_)
+            | ty::Param(_)
+            | ty::Placeholder(..)
+            | ty::Infer(_)
+            | ty::Error(_) => return,
+            ty::Bound(..) => bug!("unexpected bound type: {goal:?}"),
+            ty::Alias(_, alias_ty) => alias_ty,
+        };
+
+        for (i, (assumption, _)) in self
+            .tcx()
+            .bound_explicit_item_bounds(alias_ty.def_id)
+            .subst_iter_copied(self.tcx(), alias_ty.substs)
+            .enumerate()
+        {
+            match G::consider_assumption(self, goal, assumption) {
+                Ok(result) => {
+                    candidates.push(Candidate { source: CandidateSource::AliasBound(i), result })
+                }
+                Err(NoSolution) => (),
+            }
+        }
+    }
+
+    fn assemble_object_bound_candidates<G: GoalKind<'tcx>>(
+        &mut self,
+        goal: Goal<'tcx, G>,
+        candidates: &mut Vec<Candidate<'tcx>>,
+    ) {
+        let self_ty = goal.predicate.self_ty();
+        let bounds = match *self_ty.kind() {
+            ty::Bool
+            | ty::Char
+            | ty::Int(_)
+            | ty::Uint(_)
+            | ty::Float(_)
+            | ty::Adt(_, _)
+            | ty::Foreign(_)
+            | ty::Str
+            | ty::Array(_, _)
+            | ty::Slice(_)
+            | ty::RawPtr(_)
+            | ty::Ref(_, _, _)
+            | ty::FnDef(_, _)
+            | ty::FnPtr(_)
+            | ty::Alias(..)
+            | ty::Closure(..)
+            | ty::Generator(..)
+            | ty::GeneratorWitness(_)
+            | ty::Never
+            | ty::Tuple(_)
+            | ty::Param(_)
+            | ty::Placeholder(..)
+            | ty::Infer(_)
+            | ty::Error(_) => return,
+            ty::Bound(..) => bug!("unexpected bound type: {goal:?}"),
+            ty::Dynamic(bounds, ..) => bounds,
+        };
+
+        let tcx = self.tcx();
+        for assumption in
+            elaborate_predicates(tcx, bounds.iter().map(|bound| bound.with_self_ty(tcx, self_ty)))
+        {
+            match G::consider_assumption(self, goal, assumption.predicate) {
+                Ok(result) => {
+                    candidates.push(Candidate { source: CandidateSource::BuiltinImpl, result })
+                }
+                Err(NoSolution) => (),
+            }
+        }
+    }
 }
diff --git a/compiler/rustc_trait_selection/src/solve/cache.rs b/compiler/rustc_trait_selection/src/solve/cache.rs
deleted file mode 100644
index f1ee73a5b85..00000000000
--- a/compiler/rustc_trait_selection/src/solve/cache.rs
+++ /dev/null
@@ -1,291 +0,0 @@
-//! This module both handles the global cache which stores "finished" goals,
-//! and the provisional cache which contains partially computed goals.
-//!
-//! The provisional cache is necessary when dealing with coinductive cycles.
-//!
-//! For more information about the provisional cache and coinduction in general,
-//! check out the relevant section of the rustc-dev-guide.
-//!
-//! FIXME(@lcnr): Write that section, feel free to ping me if you need help here
-//! before then or if I still haven't done that before January 2023.
-use super::overflow::OverflowData;
-use super::{CanonicalGoal, Certainty, MaybeCause, Response};
-use super::{EvalCtxt, QueryResult};
-
-use rustc_data_structures::fx::FxHashMap;
-use rustc_infer::infer::canonical::{Canonical, CanonicalVarKind, CanonicalVarValues};
-use rustc_middle::ty::{self, TyCtxt};
-use std::{cmp::Ordering, collections::hash_map::Entry};
-
-#[derive(Debug, Clone)]
-struct ProvisionalEntry<'tcx> {
-    // In case we have a coinductive cycle, this is the
-    // the currently least restrictive result of this goal.
-    response: QueryResult<'tcx>,
-    // The lowest element on the stack on which this result
-    // relies on. Starts out as just being the depth at which
-    // we've proven this obligation, but gets lowered to the
-    // depth of another goal if we rely on it in a cycle.
-    depth: usize,
-}
-
-struct StackElem<'tcx> {
-    goal: CanonicalGoal<'tcx>,
-    has_been_used: bool,
-}
-
-/// The cache used for goals which are currently in progress or which depend
-/// on in progress results.
-///
-/// Once we're done with a goal we can store it in the global trait solver
-/// cache of the `TyCtxt`. For goals which we're currently proving, or which
-/// have only been proven via a coinductive cycle using a goal still on our stack
-/// we have to use this separate data structure.
-///
-/// The current data structure is not perfect, so there may still be room for
-/// improvement here. We have the following requirements:
-///
-/// ## Is there is a provisional entry for the given goal:
-///
-/// ```ignore (for syntax highlighting)
-/// self.entries.get(goal)
-/// ```
-///
-/// ## Get all goals on the stack involved in a cycle:
-///
-/// ```ignore (for syntax highlighting)
-/// let entry = self.entries.get(goal).unwrap();
-/// let involved_goals = self.stack.iter().skip(entry.depth);
-/// ```
-///
-/// ## Capping the depth of all entries
-///
-/// Needed whenever we encounter a cycle. The current implementation always
-/// iterates over all entries instead of only the ones with a larger depth.
-/// Changing this may result in notable performance improvements.
-///
-/// ```ignore (for syntax highlighting)
-/// let cycle_depth = self.entries.get(goal).unwrap().depth;
-/// for e in &mut self.entries {
-///     e.depth = e.depth.min(cycle_depth);
-/// }
-/// ```
-///
-/// ## Checking whether we have to rerun the current goal
-///
-/// A goal has to be rerun if its provisional result was used in a cycle
-/// and that result is different from its final result. We update
-/// [StackElem::has_been_used] for the deepest stack element involved in a cycle.
-///
-/// ## Moving all finished goals into the global cache
-///
-/// If `stack_elem.has_been_used` is true, iterate over all entries, moving the ones
-/// with equal depth. If not, simply move this single entry.
-pub(super) struct ProvisionalCache<'tcx> {
-    stack: Vec<StackElem<'tcx>>,
-    entries: FxHashMap<CanonicalGoal<'tcx>, ProvisionalEntry<'tcx>>,
-}
-
-impl<'tcx> ProvisionalCache<'tcx> {
-    pub(super) fn empty() -> ProvisionalCache<'tcx> {
-        ProvisionalCache { stack: Vec::new(), entries: Default::default() }
-    }
-
-    pub(super) fn current_depth(&self) -> usize {
-        self.stack.len()
-    }
-}
-
-impl<'tcx> EvalCtxt<'tcx> {
-    /// Tries putting the new goal on the stack, returning an error if it is already cached.
-    ///
-    /// This correctly updates the provisional cache if there is a cycle.
-    pub(super) fn try_push_stack(
-        &mut self,
-        goal: CanonicalGoal<'tcx>,
-    ) -> Result<(), QueryResult<'tcx>> {
-        // FIXME: start by checking the global cache
-
-        // Look at the provisional cache to check for cycles.
-        let cache = &mut self.provisional_cache;
-        match cache.entries.entry(goal) {
-            // No entry, simply push this goal on the stack after dealing with overflow.
-            Entry::Vacant(v) => {
-                if self.overflow_data.has_overflow(cache.stack.len()) {
-                    return Err(self.deal_with_overflow(goal));
-                }
-
-                v.insert(ProvisionalEntry {
-                    response: response_no_constraints(self.tcx, goal, Certainty::Yes),
-                    depth: cache.stack.len(),
-                });
-                cache.stack.push(StackElem { goal, has_been_used: false });
-                Ok(())
-            }
-            // We have a nested goal which relies on a goal `root` deeper in the stack.
-            //
-            // We first store that we may have to rerun `evaluate_goal` for `root` in case the
-            // provisional response is not equal to the final response. We also update the depth
-            // of all goals which recursively depend on our current goal to depend on `root`
-            // instead.
-            //
-            // Finally we can return either the provisional response for that goal if we have a
-            // coinductive cycle or an ambiguous result if the cycle is inductive.
-            Entry::Occupied(entry) => {
-                // FIXME: `ProvisionalEntry` should be `Copy`.
-                let entry = entry.get().clone();
-                cache.stack[entry.depth].has_been_used = true;
-                for provisional_entry in cache.entries.values_mut() {
-                    provisional_entry.depth = provisional_entry.depth.min(entry.depth);
-                }
-
-                // NOTE: The goals on the stack aren't the only goals involved in this cycle.
-                // We can also depend on goals which aren't part of the stack but coinductively
-                // depend on the stack themselves. We already checked whether all the goals
-                // between these goals and their root on the stack. This means that as long as
-                // each goal in a cycle is checked for coinductivity by itself simply checking
-                // the stack is enough.
-                if cache.stack[entry.depth..]
-                    .iter()
-                    .all(|g| g.goal.value.predicate.is_coinductive(self.tcx))
-                {
-                    Err(entry.response)
-                } else {
-                    Err(response_no_constraints(
-                        self.tcx,
-                        goal,
-                        Certainty::Maybe(MaybeCause::Ambiguity),
-                    ))
-                }
-            }
-        }
-    }
-
-    /// We cannot simply store the result of [EvalCtxt::compute_goal] as we have to deal with
-    /// coinductive cycles.
-    ///
-    /// When we encounter a coinductive cycle, we have to prove the final result of that cycle
-    /// while we are still computing that result. Because of this we continously recompute the
-    /// cycle until the result of the previous iteration is equal to the final result, at which
-    /// point we are done.
-    ///
-    /// This function returns `true` if we were able to finalize the goal and `false` if it has
-    /// updated the provisional cache and we have to recompute the current goal.
-    ///
-    /// FIXME: Refer to the rustc-dev-guide entry once it exists.
-    pub(super) fn try_finalize_goal(
-        &mut self,
-        actual_goal: CanonicalGoal<'tcx>,
-        response: QueryResult<'tcx>,
-    ) -> bool {
-        let cache = &mut self.provisional_cache;
-        let StackElem { goal, has_been_used } = cache.stack.pop().unwrap();
-        assert_eq!(goal, actual_goal);
-
-        let provisional_entry = cache.entries.get_mut(&goal).unwrap();
-        // Check whether the current stack entry is the root of a cycle.
-        //
-        // If so, we either move all participants of that cycle to the global cache
-        // or, in case the provisional response used in the cycle is not equal to the
-        // final response, have to recompute the goal after updating the provisional
-        // response to the final response of this iteration.
-        if has_been_used {
-            if provisional_entry.response == response {
-                // We simply drop all entries according to an immutable condition, so
-                // query instability is not a concern here.
-                #[allow(rustc::potential_query_instability)]
-                cache.entries.retain(|goal, entry| match entry.depth.cmp(&cache.stack.len()) {
-                    Ordering::Less => true,
-                    Ordering::Equal => {
-                        Self::try_move_finished_goal_to_global_cache(
-                            self.tcx,
-                            &mut self.overflow_data,
-                            &cache.stack,
-                            // FIXME: these should be `Copy` :(
-                            goal.clone(),
-                            entry.response.clone(),
-                        );
-                        false
-                    }
-                    Ordering::Greater => bug!("entry with greater depth than the current leaf"),
-                });
-
-                true
-            } else {
-                provisional_entry.response = response;
-                cache.stack.push(StackElem { goal, has_been_used: false });
-                false
-            }
-        } else {
-            Self::try_move_finished_goal_to_global_cache(
-                self.tcx,
-                &mut self.overflow_data,
-                &cache.stack,
-                goal,
-                response,
-            );
-            cache.entries.remove(&goal);
-            true
-        }
-    }
-
-    fn try_move_finished_goal_to_global_cache(
-        tcx: TyCtxt<'tcx>,
-        overflow_data: &mut OverflowData,
-        stack: &[StackElem<'tcx>],
-        goal: CanonicalGoal<'tcx>,
-        response: QueryResult<'tcx>,
-    ) {
-        // We move goals to the global cache if we either did not hit an overflow or if it's
-        // the root goal as that will now always hit the same overflow limit.
-        //
-        // NOTE: We cannot move any non-root goals to the global cache even if their final result
-        // isn't impacted by the overflow as that goal still has unstable query dependencies
-        // because it didn't go its full depth.
-        //
-        // FIXME(@lcnr): We could still cache subtrees which are not impacted by overflow though.
-        // Tracking that info correctly isn't trivial, so I haven't implemented it for now.
-        let should_cache_globally = !overflow_data.did_overflow() || stack.is_empty();
-        if should_cache_globally {
-            // FIXME: move the provisional entry to the global cache.
-            let _ = (tcx, goal, response);
-        }
-    }
-}
-
-pub(super) fn response_no_constraints<'tcx>(
-    tcx: TyCtxt<'tcx>,
-    goal: Canonical<'tcx, impl Sized>,
-    certainty: Certainty,
-) -> QueryResult<'tcx> {
-    let var_values = goal
-        .variables
-        .iter()
-        .enumerate()
-        .map(|(i, info)| match info.kind {
-            CanonicalVarKind::Ty(_) | CanonicalVarKind::PlaceholderTy(_) => {
-                tcx.mk_ty(ty::Bound(ty::INNERMOST, ty::BoundVar::from_usize(i).into())).into()
-            }
-            CanonicalVarKind::Region(_) | CanonicalVarKind::PlaceholderRegion(_) => {
-                let br = ty::BoundRegion {
-                    var: ty::BoundVar::from_usize(i),
-                    kind: ty::BrAnon(i as u32, None),
-                };
-                tcx.mk_region(ty::ReLateBound(ty::INNERMOST, br)).into()
-            }
-            CanonicalVarKind::Const(_, ty) | CanonicalVarKind::PlaceholderConst(_, ty) => tcx
-                .mk_const(ty::ConstKind::Bound(ty::INNERMOST, ty::BoundVar::from_usize(i)), ty)
-                .into(),
-        })
-        .collect();
-
-    Ok(Canonical {
-        max_universe: goal.max_universe,
-        variables: goal.variables,
-        value: Response {
-            var_values: CanonicalVarValues { var_values },
-            external_constraints: Default::default(),
-            certainty,
-        },
-    })
-}
diff --git a/compiler/rustc_trait_selection/src/solve/fulfill.rs b/compiler/rustc_trait_selection/src/solve/fulfill.rs
index dfc2b5ed329..a6240666ed4 100644
--- a/compiler/rustc_trait_selection/src/solve/fulfill.rs
+++ b/compiler/rustc_trait_selection/src/solve/fulfill.rs
@@ -10,7 +10,7 @@ use rustc_infer::{
 };
 use rustc_middle::ty;
 
-use super::{Certainty, EvalCtxt};
+use super::{search_graph, Certainty, EvalCtxt};
 
 /// A trait engine using the new trait solver.
 ///
@@ -52,7 +52,7 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
             .drain(..)
             .map(|obligation| FulfillmentError {
                 obligation: obligation.clone(),
-                code: FulfillmentErrorCode::CodeSelectionError(SelectionError::Unimplemented),
+                code: FulfillmentErrorCode::CodeAmbiguity,
                 root_obligation: obligation,
             })
             .collect()
@@ -67,14 +67,17 @@ impl<'tcx> TraitEngine<'tcx> for FulfillmentCtxt<'tcx> {
 
             let mut has_changed = false;
             for obligation in mem::take(&mut self.obligations) {
-                let mut cx = EvalCtxt::new(infcx.tcx);
-                let (changed, certainty) = match cx.evaluate_goal(infcx, obligation.clone().into())
-                {
+                let goal = obligation.clone().into();
+                let search_graph = &mut search_graph::SearchGraph::new(infcx.tcx);
+                let mut ecx = EvalCtxt::new_outside_solver(infcx, search_graph);
+                let (changed, certainty) = match ecx.evaluate_goal(goal) {
                     Ok(result) => result,
                     Err(NoSolution) => {
                         errors.push(FulfillmentError {
                             obligation: obligation.clone(),
-                            code: FulfillmentErrorCode::CodeAmbiguity,
+                            code: FulfillmentErrorCode::CodeSelectionError(
+                                SelectionError::Unimplemented,
+                            ),
                             root_obligation: obligation,
                         });
                         continue;
diff --git a/compiler/rustc_trait_selection/src/solve/infcx_ext.rs b/compiler/rustc_trait_selection/src/solve/infcx_ext.rs
index 436f4eea662..42f597c781d 100644
--- a/compiler/rustc_trait_selection/src/solve/infcx_ext.rs
+++ b/compiler/rustc_trait_selection/src/solve/infcx_ext.rs
@@ -1,23 +1,35 @@
-use rustc_infer::infer::canonical::CanonicalVarValues;
+use rustc_infer::infer::at::ToTrace;
 use rustc_infer::infer::type_variable::{TypeVariableOrigin, TypeVariableOriginKind};
-use rustc_infer::infer::InferCtxt;
+use rustc_infer::infer::{InferCtxt, InferOk, LateBoundRegionConversionTime};
 use rustc_infer::traits::query::NoSolution;
-use rustc_middle::ty::Ty;
+use rustc_infer::traits::ObligationCause;
+use rustc_middle::infer::unify_key::{ConstVariableOrigin, ConstVariableOriginKind};
+use rustc_middle::ty::{self, Ty, TypeFoldable};
 use rustc_span::DUMMY_SP;
 
-use crate::solve::ExternalConstraints;
-
-use super::{Certainty, QueryResult, Response};
+use super::Goal;
 
 /// Methods used inside of the canonical queries of the solver.
+///
+/// Most notably these do not care about diagnostics information.
+/// If you find this while looking for methods to use outside of the
+/// solver, you may look at the implementation of these method for
+/// help.
 pub(super) trait InferCtxtExt<'tcx> {
     fn next_ty_infer(&self) -> Ty<'tcx>;
+    fn next_const_infer(&self, ty: Ty<'tcx>) -> ty::Const<'tcx>;
+
+    fn eq<T: ToTrace<'tcx>>(
+        &self,
+        param_env: ty::ParamEnv<'tcx>,
+        lhs: T,
+        rhs: T,
+    ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution>;
 
-    fn make_canonical_response(
+    fn instantiate_bound_vars_with_infer<T: TypeFoldable<'tcx> + Copy>(
         &self,
-        var_values: CanonicalVarValues<'tcx>,
-        certainty: Certainty,
-    ) -> QueryResult<'tcx>;
+        value: ty::Binder<'tcx, T>,
+    ) -> T;
 }
 
 impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
@@ -27,29 +39,40 @@ impl<'tcx> InferCtxtExt<'tcx> for InferCtxt<'tcx> {
             span: DUMMY_SP,
         })
     }
+    fn next_const_infer(&self, ty: Ty<'tcx>) -> ty::Const<'tcx> {
+        self.next_const_var(
+            ty,
+            ConstVariableOrigin { kind: ConstVariableOriginKind::MiscVariable, span: DUMMY_SP },
+        )
+    }
 
-    fn make_canonical_response(
+    #[instrument(level = "debug", skip(self, param_env), ret)]
+    fn eq<T: ToTrace<'tcx>>(
         &self,
-        var_values: CanonicalVarValues<'tcx>,
-        certainty: Certainty,
-    ) -> QueryResult<'tcx> {
-        let external_constraints = take_external_constraints(self)?;
-
-        Ok(self.canonicalize_response(Response { var_values, external_constraints, certainty }))
+        param_env: ty::ParamEnv<'tcx>,
+        lhs: T,
+        rhs: T,
+    ) -> Result<Vec<Goal<'tcx, ty::Predicate<'tcx>>>, NoSolution> {
+        self.at(&ObligationCause::dummy(), param_env)
+            .define_opaque_types(false)
+            .eq(lhs, rhs)
+            .map(|InferOk { value: (), obligations }| {
+                obligations.into_iter().map(|o| o.into()).collect()
+            })
+            .map_err(|e| {
+                debug!(?e, "failed to equate");
+                NoSolution
+            })
     }
-}
 
-#[instrument(level = "debug", skip(infcx), ret)]
-fn take_external_constraints<'tcx>(
-    infcx: &InferCtxt<'tcx>,
-) -> Result<ExternalConstraints<'tcx>, NoSolution> {
-    let region_obligations = infcx.take_registered_region_obligations();
-    let opaque_types = infcx.take_opaque_types_for_query_response();
-    Ok(ExternalConstraints {
-        // FIXME: Now that's definitely wrong :)
-        //
-        // Should also do the leak check here I think
-        regions: drop(region_obligations),
-        opaque_types,
-    })
+    fn instantiate_bound_vars_with_infer<T: TypeFoldable<'tcx> + Copy>(
+        &self,
+        value: ty::Binder<'tcx, T>,
+    ) -> T {
+        self.replace_bound_vars_with_fresh_vars(
+            DUMMY_SP,
+            LateBoundRegionConversionTime::HigherRankedType,
+            value,
+        )
+    }
 }
diff --git a/compiler/rustc_trait_selection/src/solve/mod.rs b/compiler/rustc_trait_selection/src/solve/mod.rs
index 042ba96b379..da2a1a19957 100644
--- a/compiler/rustc_trait_selection/src/solve/mod.rs
+++ b/compiler/rustc_trait_selection/src/solve/mod.rs
@@ -19,27 +19,26 @@
 
 use std::mem;
 
+use rustc_hir::def_id::DefId;
+use rustc_infer::infer::canonical::{Canonical, CanonicalVarKind, CanonicalVarValues};
 use rustc_infer::infer::canonical::{OriginalQueryValues, QueryRegionConstraints, QueryResponse};
 use rustc_infer::infer::{InferCtxt, InferOk, TyCtxtInferExt};
 use rustc_infer::traits::query::NoSolution;
 use rustc_infer::traits::Obligation;
 use rustc_middle::infer::canonical::Certainty as OldCertainty;
-use rustc_middle::infer::canonical::{Canonical, CanonicalVarValues};
 use rustc_middle::ty::{self, Ty, TyCtxt};
-use rustc_middle::ty::{RegionOutlivesPredicate, ToPredicate, TypeOutlivesPredicate};
+use rustc_middle::ty::{
+    CoercePredicate, RegionOutlivesPredicate, SubtypePredicate, ToPredicate, TypeOutlivesPredicate,
+};
 use rustc_span::DUMMY_SP;
 
 use crate::traits::ObligationCause;
 
-use self::cache::response_no_constraints;
-use self::infcx_ext::InferCtxtExt;
-
 mod assembly;
-mod cache;
 mod fulfill;
 mod infcx_ext;
-mod overflow;
 mod project_goals;
+mod search_graph;
 mod trait_goals;
 
 pub use fulfill::FulfillmentCtxt;
@@ -91,6 +90,8 @@ pub enum Certainty {
 }
 
 impl Certainty {
+    pub const AMBIGUOUS: Certainty = Certainty::Maybe(MaybeCause::Ambiguity);
+
     /// When proving multiple goals using **AND**, e.g. nested obligations for an impl,
     /// use this function to unify the certainty of these goals
     pub fn unify_and(self, other: Certainty) -> Certainty {
@@ -146,45 +147,42 @@ pub trait TyCtxtExt<'tcx> {
 
 impl<'tcx> TyCtxtExt<'tcx> for TyCtxt<'tcx> {
     fn evaluate_goal(self, goal: CanonicalGoal<'tcx>) -> QueryResult<'tcx> {
-        let mut cx = EvalCtxt::new(self);
-        cx.evaluate_canonical_goal(goal)
+        let mut search_graph = search_graph::SearchGraph::new(self);
+        EvalCtxt::evaluate_canonical_goal(self, &mut search_graph, goal)
     }
 }
 
-struct EvalCtxt<'tcx> {
-    tcx: TyCtxt<'tcx>,
+struct EvalCtxt<'a, 'tcx> {
+    infcx: &'a InferCtxt<'tcx>,
+    var_values: CanonicalVarValues<'tcx>,
 
-    provisional_cache: cache::ProvisionalCache<'tcx>,
-    overflow_data: overflow::OverflowData,
+    search_graph: &'a mut search_graph::SearchGraph<'tcx>,
 }
 
-impl<'tcx> EvalCtxt<'tcx> {
-    fn new(tcx: TyCtxt<'tcx>) -> EvalCtxt<'tcx> {
-        EvalCtxt {
-            tcx,
-            provisional_cache: cache::ProvisionalCache::empty(),
-            overflow_data: overflow::OverflowData::new(tcx),
-        }
+impl<'a, 'tcx> EvalCtxt<'a, 'tcx> {
+    fn tcx(&self) -> TyCtxt<'tcx> {
+        self.infcx.tcx
     }
 
-    /// Recursively evaluates `goal`, returning whether any inference vars have
-    /// been constrained and the certainty of the result.
-    fn evaluate_goal(
-        &mut self,
-        infcx: &InferCtxt<'tcx>,
-        goal: Goal<'tcx, ty::Predicate<'tcx>>,
-    ) -> Result<(bool, Certainty), NoSolution> {
-        let mut orig_values = OriginalQueryValues::default();
-        let canonical_goal = infcx.canonicalize_query(goal, &mut orig_values);
-        let canonical_response = self.evaluate_canonical_goal(canonical_goal)?;
-        Ok((
-            true, // FIXME: check whether `var_values` are an identity substitution.
-            instantiate_canonical_query_response(infcx, &orig_values, canonical_response),
-        ))
+    /// Creates a new evaluation context outside of the trait solver.
+    ///
+    /// With this solver making a canonical response doesn't make much sense.
+    /// The `search_graph` for this solver has to be completely empty.
+    fn new_outside_solver(
+        infcx: &'a InferCtxt<'tcx>,
+        search_graph: &'a mut search_graph::SearchGraph<'tcx>,
+    ) -> EvalCtxt<'a, 'tcx> {
+        assert!(search_graph.is_empty());
+        EvalCtxt { infcx, var_values: CanonicalVarValues::dummy(), search_graph }
     }
 
-    fn evaluate_canonical_goal(&mut self, goal: CanonicalGoal<'tcx>) -> QueryResult<'tcx> {
-        match self.try_push_stack(goal) {
+    #[instrument(level = "debug", skip(tcx, search_graph), ret)]
+    fn evaluate_canonical_goal(
+        tcx: TyCtxt<'tcx>,
+        search_graph: &'a mut search_graph::SearchGraph<'tcx>,
+        canonical_goal: CanonicalGoal<'tcx>,
+    ) -> QueryResult<'tcx> {
+        match search_graph.try_push_stack(tcx, canonical_goal) {
             Ok(()) => {}
             // Our goal is already on the stack, eager return.
             Err(response) => return response,
@@ -195,93 +193,169 @@ impl<'tcx> EvalCtxt<'tcx> {
         //
         // FIXME: Similar to `evaluate_all`, this has to check for overflow.
         loop {
-            let result = self.compute_goal(goal);
+            let (ref infcx, goal, var_values) =
+                tcx.infer_ctxt().build_with_canonical(DUMMY_SP, &canonical_goal);
+            let mut ecx = EvalCtxt { infcx, var_values, search_graph };
+            let result = ecx.compute_goal(goal);
 
             // FIXME: `Response` should be `Copy`
-            if self.try_finalize_goal(goal, result.clone()) {
+            if search_graph.try_finalize_goal(tcx, canonical_goal, result.clone()) {
                 return result;
             }
         }
     }
 
-    fn compute_goal(&mut self, canonical_goal: CanonicalGoal<'tcx>) -> QueryResult<'tcx> {
-        // WARNING: We're looking at a canonical value without instantiating it here.
-        //
-        // We have to be incredibly careful to not change the order of bound variables or
-        // remove any. As we go from `Goal<'tcx, Predicate>` to `Goal` with the variants
-        // of `PredicateKind` this is the case and it is and faster than instantiating and
-        // recanonicalizing.
-        let Goal { param_env, predicate } = canonical_goal.value;
+    fn make_canonical_response(&self, certainty: Certainty) -> QueryResult<'tcx> {
+        let external_constraints = take_external_constraints(self.infcx)?;
+
+        Ok(self.infcx.canonicalize_response(Response {
+            var_values: self.var_values.clone(),
+            external_constraints,
+            certainty,
+        }))
+    }
 
-        if let Some(kind) = predicate.kind().no_bound_vars_ignoring_escaping(self.tcx) {
+    /// Recursively evaluates `goal`, returning whether any inference vars have
+    /// been constrained and the certainty of the result.
+    fn evaluate_goal(
+        &mut self,
+        goal: Goal<'tcx, ty::Predicate<'tcx>>,
+    ) -> Result<(bool, Certainty), NoSolution> {
+        let mut orig_values = OriginalQueryValues::default();
+        let canonical_goal = self.infcx.canonicalize_query(goal, &mut orig_values);
+        let canonical_response =
+            EvalCtxt::evaluate_canonical_goal(self.tcx(), self.search_graph, canonical_goal)?;
+        Ok((
+            !canonical_response.value.var_values.is_identity(),
+            instantiate_canonical_query_response(self.infcx, &orig_values, canonical_response),
+        ))
+    }
+
+    fn compute_goal(&mut self, goal: Goal<'tcx, ty::Predicate<'tcx>>) -> QueryResult<'tcx> {
+        let Goal { param_env, predicate } = goal;
+        let kind = predicate.kind();
+        if let Some(kind) = kind.no_bound_vars() {
             match kind {
-                ty::PredicateKind::Clause(ty::Clause::Trait(predicate)) => self.compute_trait_goal(
-                    canonical_goal.unchecked_rebind(Goal { param_env, predicate }),
-                ),
-                ty::PredicateKind::Clause(ty::Clause::Projection(predicate)) => self
-                    .compute_projection_goal(
-                        canonical_goal.unchecked_rebind(Goal { param_env, predicate }),
-                    ),
-                ty::PredicateKind::Clause(ty::Clause::TypeOutlives(predicate)) => self
-                    .compute_type_outlives_goal(
-                        canonical_goal.unchecked_rebind(Goal { param_env, predicate }),
-                    ),
-                ty::PredicateKind::Clause(ty::Clause::RegionOutlives(predicate)) => self
-                    .compute_region_outlives_goal(
-                        canonical_goal.unchecked_rebind(Goal { param_env, predicate }),
-                    ),
+                ty::PredicateKind::Clause(ty::Clause::Trait(predicate)) => {
+                    self.compute_trait_goal(Goal { param_env, predicate })
+                }
+                ty::PredicateKind::Clause(ty::Clause::Projection(predicate)) => {
+                    self.compute_projection_goal(Goal { param_env, predicate })
+                }
+                ty::PredicateKind::Clause(ty::Clause::TypeOutlives(predicate)) => {
+                    self.compute_type_outlives_goal(Goal { param_env, predicate })
+                }
+                ty::PredicateKind::Clause(ty::Clause::RegionOutlives(predicate)) => {
+                    self.compute_region_outlives_goal(Goal { param_env, predicate })
+                }
+                ty::PredicateKind::Subtype(predicate) => {
+                    self.compute_subtype_goal(Goal { param_env, predicate })
+                }
+                ty::PredicateKind::Coerce(predicate) => {
+                    self.compute_coerce_goal(Goal { param_env, predicate })
+                }
+                ty::PredicateKind::ClosureKind(def_id, substs, kind) => self
+                    .compute_closure_kind_goal(Goal {
+                        param_env,
+                        predicate: (def_id, substs, kind),
+                    }),
+                ty::PredicateKind::Ambiguous => self.make_canonical_response(Certainty::AMBIGUOUS),
                 // FIXME: implement these predicates :)
                 ty::PredicateKind::WellFormed(_)
                 | ty::PredicateKind::ObjectSafe(_)
-                | ty::PredicateKind::ClosureKind(_, _, _)
-                | ty::PredicateKind::Subtype(_)
-                | ty::PredicateKind::Coerce(_)
                 | ty::PredicateKind::ConstEvaluatable(_)
-                | ty::PredicateKind::ConstEquate(_, _)
-                | ty::PredicateKind::TypeWellFormedFromEnv(_)
-                | ty::PredicateKind::Ambiguous => {
-                    // FIXME
-                    response_no_constraints(self.tcx, canonical_goal, Certainty::Yes)
+                | ty::PredicateKind::ConstEquate(_, _) => {
+                    self.make_canonical_response(Certainty::Yes)
+                }
+                ty::PredicateKind::TypeWellFormedFromEnv(..) => {
+                    bug!("TypeWellFormedFromEnv is only used for Chalk")
                 }
             }
         } else {
-            let (infcx, goal, var_values) =
-                self.tcx.infer_ctxt().build_with_canonical(DUMMY_SP, &canonical_goal);
-            let kind = infcx.replace_bound_vars_with_placeholders(goal.predicate.kind());
-            let goal = goal.with(self.tcx, ty::Binder::dummy(kind));
-            let (_, certainty) = self.evaluate_goal(&infcx, goal)?;
-            infcx.make_canonical_response(var_values, certainty)
+            let kind = self.infcx.replace_bound_vars_with_placeholders(kind);
+            let goal = goal.with(self.tcx(), ty::Binder::dummy(kind));
+            let (_, certainty) = self.evaluate_goal(goal)?;
+            self.make_canonical_response(certainty)
         }
     }
 
     fn compute_type_outlives_goal(
         &mut self,
-        goal: CanonicalGoal<'tcx, TypeOutlivesPredicate<'tcx>>,
+        _goal: Goal<'tcx, TypeOutlivesPredicate<'tcx>>,
     ) -> QueryResult<'tcx> {
-        // FIXME
-        response_no_constraints(self.tcx, goal, Certainty::Yes)
+        self.make_canonical_response(Certainty::Yes)
     }
 
     fn compute_region_outlives_goal(
         &mut self,
-        goal: CanonicalGoal<'tcx, RegionOutlivesPredicate<'tcx>>,
+        _goal: Goal<'tcx, RegionOutlivesPredicate<'tcx>>,
+    ) -> QueryResult<'tcx> {
+        self.make_canonical_response(Certainty::Yes)
+    }
+
+    fn compute_coerce_goal(
+        &mut self,
+        goal: Goal<'tcx, CoercePredicate<'tcx>>,
+    ) -> QueryResult<'tcx> {
+        self.compute_subtype_goal(Goal {
+            param_env: goal.param_env,
+            predicate: SubtypePredicate {
+                a_is_expected: false,
+                a: goal.predicate.a,
+                b: goal.predicate.b,
+            },
+        })
+    }
+
+    fn compute_subtype_goal(
+        &mut self,
+        goal: Goal<'tcx, SubtypePredicate<'tcx>>,
+    ) -> QueryResult<'tcx> {
+        if goal.predicate.a.is_ty_var() && goal.predicate.b.is_ty_var() {
+            // FIXME: Do we want to register a subtype relation between these vars?
+            // That won't actually reflect in the query response, so it seems moot.
+            self.make_canonical_response(Certainty::AMBIGUOUS)
+        } else {
+            self.infcx.probe(|_| {
+                let InferOk { value: (), obligations } = self
+                    .infcx
+                    .at(&ObligationCause::dummy(), goal.param_env)
+                    .sub(goal.predicate.a, goal.predicate.b)?;
+                self.evaluate_all_and_make_canonical_response(
+                    obligations.into_iter().map(|pred| pred.into()).collect(),
+                )
+            })
+        }
+    }
+
+    fn compute_closure_kind_goal(
+        &mut self,
+        goal: Goal<'tcx, (DefId, ty::SubstsRef<'tcx>, ty::ClosureKind)>,
     ) -> QueryResult<'tcx> {
-        // FIXME
-        response_no_constraints(self.tcx, goal, Certainty::Yes)
+        let (_, substs, expected_kind) = goal.predicate;
+        let found_kind = substs.as_closure().kind_ty().to_opt_closure_kind();
+
+        let Some(found_kind) = found_kind else {
+            return self.make_canonical_response(Certainty::AMBIGUOUS);
+        };
+        if found_kind.extends(expected_kind) {
+            self.make_canonical_response(Certainty::Yes)
+        } else {
+            Err(NoSolution)
+        }
     }
 }
 
-impl<'tcx> EvalCtxt<'tcx> {
+impl<'tcx> EvalCtxt<'_, 'tcx> {
     fn evaluate_all(
         &mut self,
-        infcx: &InferCtxt<'tcx>,
         mut goals: Vec<Goal<'tcx, ty::Predicate<'tcx>>>,
     ) -> Result<Certainty, NoSolution> {
         let mut new_goals = Vec::new();
         self.repeat_while_none(|this| {
             let mut has_changed = Err(Certainty::Yes);
             for goal in goals.drain(..) {
-                let (changed, certainty) = match this.evaluate_goal(infcx, goal) {
+                let (changed, certainty) = match this.evaluate_goal(goal) {
                     Ok(result) => result,
                     Err(NoSolution) => return Some(Err(NoSolution)),
                 };
@@ -308,6 +382,28 @@ impl<'tcx> EvalCtxt<'tcx> {
             }
         })
     }
+
+    fn evaluate_all_and_make_canonical_response(
+        &mut self,
+        goals: Vec<Goal<'tcx, ty::Predicate<'tcx>>>,
+    ) -> QueryResult<'tcx> {
+        self.evaluate_all(goals).and_then(|certainty| self.make_canonical_response(certainty))
+    }
+}
+
+#[instrument(level = "debug", skip(infcx), ret)]
+fn take_external_constraints<'tcx>(
+    infcx: &InferCtxt<'tcx>,
+) -> Result<ExternalConstraints<'tcx>, NoSolution> {
+    let region_obligations = infcx.take_registered_region_obligations();
+    let opaque_types = infcx.take_opaque_types_for_query_response();
+    Ok(ExternalConstraints {
+        // FIXME: Now that's definitely wrong :)
+        //
+        // Should also do the leak check here I think
+        regions: drop(region_obligations),
+        opaque_types,
+    })
 }
 
 fn instantiate_canonical_query_response<'tcx>(
@@ -334,3 +430,40 @@ fn instantiate_canonical_query_response<'tcx>(
     assert!(obligations.is_empty());
     value
 }
+
+pub(super) fn response_no_constraints<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    goal: Canonical<'tcx, impl Sized>,
+    certainty: Certainty,
+) -> QueryResult<'tcx> {
+    let var_values = goal
+        .variables
+        .iter()
+        .enumerate()
+        .map(|(i, info)| match info.kind {
+            CanonicalVarKind::Ty(_) | CanonicalVarKind::PlaceholderTy(_) => {
+                tcx.mk_ty(ty::Bound(ty::INNERMOST, ty::BoundVar::from_usize(i).into())).into()
+            }
+            CanonicalVarKind::Region(_) | CanonicalVarKind::PlaceholderRegion(_) => {
+                let br = ty::BoundRegion {
+                    var: ty::BoundVar::from_usize(i),
+                    kind: ty::BrAnon(i as u32, None),
+                };
+                tcx.mk_region(ty::ReLateBound(ty::INNERMOST, br)).into()
+            }
+            CanonicalVarKind::Const(_, ty) | CanonicalVarKind::PlaceholderConst(_, ty) => tcx
+                .mk_const(ty::ConstKind::Bound(ty::INNERMOST, ty::BoundVar::from_usize(i)), ty)
+                .into(),
+        })
+        .collect();
+
+    Ok(Canonical {
+        max_universe: goal.max_universe,
+        variables: goal.variables,
+        value: Response {
+            var_values: CanonicalVarValues { var_values },
+            external_constraints: Default::default(),
+            certainty,
+        },
+    })
+}
diff --git a/compiler/rustc_trait_selection/src/solve/project_goals.rs b/compiler/rustc_trait_selection/src/solve/project_goals.rs
index e9140507192..32e15f03998 100644
--- a/compiler/rustc_trait_selection/src/solve/project_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/project_goals.rs
@@ -1,38 +1,124 @@
 use crate::traits::{specialization_graph, translate_substs};
 
-use super::assembly::{self, AssemblyCtxt};
-use super::{CanonicalGoal, EvalCtxt, Goal, QueryResult};
+use super::assembly::{self, Candidate, CandidateSource};
+use super::infcx_ext::InferCtxtExt;
+use super::trait_goals::structural_traits;
+use super::{Certainty, EvalCtxt, Goal, QueryResult};
 use rustc_errors::ErrorGuaranteed;
 use rustc_hir::def::DefKind;
 use rustc_hir::def_id::DefId;
-use rustc_infer::infer::{InferCtxt, InferOk};
+use rustc_infer::infer::InferCtxt;
 use rustc_infer::traits::query::NoSolution;
 use rustc_infer::traits::specialization_graph::LeafDef;
-use rustc_infer::traits::{ObligationCause, Reveal};
+use rustc_infer::traits::Reveal;
 use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
-use rustc_middle::ty::ProjectionPredicate;
-use rustc_middle::ty::TypeVisitable;
 use rustc_middle::ty::{self, Ty, TyCtxt};
+use rustc_middle::ty::{ProjectionPredicate, TypeSuperVisitable, TypeVisitor};
+use rustc_middle::ty::{ToPredicate, TypeVisitable};
 use rustc_span::DUMMY_SP;
 use std::iter;
+use std::ops::ControlFlow;
 
-#[allow(dead_code)] // FIXME: implement and use all variants.
-#[derive(Debug, Clone, Copy)]
-pub(super) enum CandidateSource {
-    Impl(DefId),
-    ParamEnv(usize),
-    Builtin,
-}
-
-type Candidate<'tcx> = assembly::Candidate<'tcx, ProjectionPredicate<'tcx>>;
-
-impl<'tcx> EvalCtxt<'tcx> {
+impl<'tcx> EvalCtxt<'_, 'tcx> {
     pub(super) fn compute_projection_goal(
         &mut self,
-        goal: CanonicalGoal<'tcx, ProjectionPredicate<'tcx>>,
+        goal: Goal<'tcx, ProjectionPredicate<'tcx>>,
     ) -> QueryResult<'tcx> {
-        let candidates = AssemblyCtxt::assemble_and_evaluate_candidates(self, goal);
-        self.merge_project_candidates(candidates)
+        // To only compute normalization once for each projection we only
+        // normalize if the expected term is an unconstrained inference variable.
+        //
+        // E.g. for `<T as Trait>::Assoc = u32` we recursively compute the goal
+        // `exists<U> <T as Trait>::Assoc = U` and then take the resulting type for
+        // `U` and equate it with `u32`. This means that we don't need a separate
+        // projection cache in the solver.
+        if self.term_is_fully_unconstrained(goal) {
+            let candidates = self.assemble_and_evaluate_candidates(goal);
+            self.merge_project_candidates(candidates)
+        } else {
+            let predicate = goal.predicate;
+            let unconstrained_rhs = match predicate.term.unpack() {
+                ty::TermKind::Ty(_) => self.infcx.next_ty_infer().into(),
+                ty::TermKind::Const(ct) => self.infcx.next_const_infer(ct.ty()).into(),
+            };
+            let unconstrained_predicate = ty::Clause::Projection(ProjectionPredicate {
+                projection_ty: goal.predicate.projection_ty,
+                term: unconstrained_rhs,
+            });
+            let (_has_changed, normalize_certainty) =
+                self.evaluate_goal(goal.with(self.tcx(), unconstrained_predicate))?;
+
+            let nested_eq_goals =
+                self.infcx.eq(goal.param_env, unconstrained_rhs, predicate.term)?;
+            let eval_certainty = self.evaluate_all(nested_eq_goals)?;
+            self.make_canonical_response(normalize_certainty.unify_and(eval_certainty))
+        }
+    }
+
+    /// Is the projection predicate is of the form `exists<T> <Ty as Trait>::Assoc = T`.
+    ///
+    /// This is the case if the `term` is an inference variable in the innermost universe
+    /// and does not occur in any other part of the predicate.
+    fn term_is_fully_unconstrained(&self, goal: Goal<'tcx, ProjectionPredicate<'tcx>>) -> bool {
+        let infcx = self.infcx;
+        let term_is_infer = match goal.predicate.term.unpack() {
+            ty::TermKind::Ty(ty) => {
+                if let &ty::Infer(ty::TyVar(vid)) = ty.kind() {
+                    match infcx.probe_ty_var(vid) {
+                        Ok(value) => bug!("resolved var in query: {goal:?} {value:?}"),
+                        Err(universe) => universe == infcx.universe(),
+                    }
+                } else {
+                    false
+                }
+            }
+            ty::TermKind::Const(ct) => {
+                if let ty::ConstKind::Infer(ty::InferConst::Var(vid)) = ct.kind() {
+                    match self.infcx.probe_const_var(vid) {
+                        Ok(value) => bug!("resolved var in query: {goal:?} {value:?}"),
+                        Err(universe) => universe == infcx.universe(),
+                    }
+                } else {
+                    false
+                }
+            }
+        };
+
+        // Guard against `<T as Trait<?0>>::Assoc = ?0>`.
+        struct ContainsTerm<'tcx> {
+            term: ty::Term<'tcx>,
+        }
+        impl<'tcx> TypeVisitor<'tcx> for ContainsTerm<'tcx> {
+            type BreakTy = ();
+            fn visit_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
+                if t.needs_infer() {
+                    if ty::Term::from(t) == self.term {
+                        ControlFlow::BREAK
+                    } else {
+                        t.super_visit_with(self)
+                    }
+                } else {
+                    ControlFlow::CONTINUE
+                }
+            }
+
+            fn visit_const(&mut self, c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
+                if c.needs_infer() {
+                    if ty::Term::from(c) == self.term {
+                        ControlFlow::BREAK
+                    } else {
+                        c.super_visit_with(self)
+                    }
+                } else {
+                    ControlFlow::CONTINUE
+                }
+            }
+        }
+
+        let mut visitor = ContainsTerm { term: goal.predicate.term };
+
+        term_is_infer
+            && goal.predicate.projection_ty.visit_with(&mut visitor).is_continue()
+            && goal.param_env.visit_with(&mut visitor).is_continue()
     }
 
     fn merge_project_candidates(
@@ -83,14 +169,13 @@ impl<'tcx> EvalCtxt<'tcx> {
         match (candidate.source, other.source) {
             (CandidateSource::Impl(_), _)
             | (CandidateSource::ParamEnv(_), _)
-            | (CandidateSource::Builtin, _) => unimplemented!(),
+            | (CandidateSource::BuiltinImpl, _)
+            | (CandidateSource::AliasBound(_), _) => unimplemented!(),
         }
     }
 }
 
 impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
-    type CandidateSource = CandidateSource;
-
     fn self_ty(self) -> Ty<'tcx> {
         self.self_ty()
     }
@@ -104,33 +189,26 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
     }
 
     fn consider_impl_candidate(
-        acx: &mut AssemblyCtxt<'_, 'tcx, ProjectionPredicate<'tcx>>,
+        ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, ProjectionPredicate<'tcx>>,
         impl_def_id: DefId,
-    ) {
-        let tcx = acx.cx.tcx;
+    ) -> QueryResult<'tcx> {
+        let tcx = ecx.tcx();
+
         let goal_trait_ref = goal.predicate.projection_ty.trait_ref(tcx);
         let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
         let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::AsPlaceholder };
         if iter::zip(goal_trait_ref.substs, impl_trait_ref.skip_binder().substs)
             .any(|(goal, imp)| !drcx.generic_args_may_unify(goal, imp))
         {
-            return;
+            return Err(NoSolution);
         }
 
-        acx.infcx.probe(|_| {
-            let impl_substs = acx.infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id);
+        ecx.infcx.probe(|_| {
+            let impl_substs = ecx.infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id);
             let impl_trait_ref = impl_trait_ref.subst(tcx, impl_substs);
 
-            let Ok(InferOk { obligations, .. }) = acx
-                .infcx
-                .at(&ObligationCause::dummy(), goal.param_env)
-                .define_opaque_types(false)
-                .eq(goal_trait_ref, impl_trait_ref)
-                .map_err(|e| debug!("failed to equate trait refs: {e:?}"))
-            else {
-                return
-            };
+            let mut nested_goals = ecx.infcx.eq(goal.param_env, goal_trait_ref, impl_trait_ref)?;
             let where_clause_bounds = tcx
                 .predicates_of(impl_def_id)
                 .instantiate(tcx, impl_substs)
@@ -138,17 +216,20 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
                 .into_iter()
                 .map(|pred| goal.with(tcx, pred));
 
-            let nested_goals = obligations.into_iter().map(|o| o.into()).chain(where_clause_bounds).collect();
-            let Ok(trait_ref_certainty) = acx.cx.evaluate_all(acx.infcx, nested_goals) else { return };
+            nested_goals.extend(where_clause_bounds);
+            let trait_ref_certainty = ecx.evaluate_all(nested_goals)?;
 
+            // In case the associated item is hidden due to specialization, we have to
+            // return ambiguity this would otherwise be incomplete, resulting in
+            // unsoundness during coherence (#105782).
             let Some(assoc_def) = fetch_eligible_assoc_item_def(
-                acx.infcx,
+                ecx.infcx,
                 goal.param_env,
                 goal_trait_ref,
                 goal.predicate.def_id(),
                 impl_def_id
-            ) else {
-                return
+            )? else {
+                return ecx.make_canonical_response(trait_ref_certainty.unify_and(Certainty::AMBIGUOUS));
             };
 
             if !assoc_def.item.defaultness(tcx).has_value() {
@@ -171,10 +252,10 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
             let impl_substs_with_gat = goal.predicate.projection_ty.substs.rebase_onto(
                 tcx,
                 goal_trait_ref.def_id,
-                impl_trait_ref.substs,
+                impl_substs,
             );
             let substs = translate_substs(
-                acx.infcx,
+                ecx.infcx,
                 goal.param_env,
                 impl_def_id,
                 impl_substs_with_gat,
@@ -185,7 +266,8 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
             let is_const = matches!(tcx.def_kind(assoc_def.item.def_id), DefKind::AssocConst);
             let ty = tcx.bound_type_of(assoc_def.item.def_id);
             let term: ty::EarlyBinder<ty::Term<'tcx>> = if is_const {
-                let identity_substs = ty::InternalSubsts::identity_for_item(tcx, assoc_def.item.def_id);
+                let identity_substs =
+                    ty::InternalSubsts::identity_for_item(tcx, assoc_def.item.def_id);
                 let did = ty::WithOptConstParam::unknown(assoc_def.item.def_id);
                 let kind =
                     ty::ConstKind::Unevaluated(ty::UnevaluatedConst::new(did, identity_substs));
@@ -194,23 +276,121 @@ impl<'tcx> assembly::GoalKind<'tcx> for ProjectionPredicate<'tcx> {
                 ty.map_bound(|ty| ty.into())
             };
 
-            let Ok(InferOk { obligations, .. }) = acx
+            // The term of our goal should be fully unconstrained, so this should never fail.
+            //
+            // It can however be ambiguous when the resolved type is a projection.
+            let nested_goals = ecx
                 .infcx
-                .at(&ObligationCause::dummy(), goal.param_env)
-                .define_opaque_types(false)
-                .eq(goal.predicate.term,  term.subst(tcx, substs))
-                .map_err(|e| debug!("failed to equate trait refs: {e:?}"))
-            else {
-                return
-            };
-
-            let nested_goals = obligations.into_iter().map(|o| o.into()).collect();
-            let Ok(rhs_certainty) = acx.cx.evaluate_all(acx.infcx, nested_goals) else { return };
+                .eq(goal.param_env, goal.predicate.term, term.subst(tcx, substs))
+                .expect("failed to unify with unconstrained term");
+            let rhs_certainty =
+                ecx.evaluate_all(nested_goals).expect("failed to unify with unconstrained term");
 
-            let certainty = trait_ref_certainty.unify_and(rhs_certainty);
-            acx.try_insert_candidate(CandidateSource::Impl(impl_def_id), certainty);
+            ecx.make_canonical_response(trait_ref_certainty.unify_and(rhs_certainty))
         })
     }
+
+    fn consider_assumption(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+        assumption: ty::Predicate<'tcx>,
+    ) -> QueryResult<'tcx> {
+        if let Some(poly_projection_pred) = assumption.to_opt_poly_projection_pred() {
+            ecx.infcx.probe(|_| {
+                let assumption_projection_pred =
+                    ecx.infcx.instantiate_bound_vars_with_infer(poly_projection_pred);
+                let nested_goals = ecx.infcx.eq(
+                    goal.param_env,
+                    goal.predicate.projection_ty,
+                    assumption_projection_pred.projection_ty,
+                )?;
+                let subst_certainty = ecx.evaluate_all(nested_goals)?;
+
+                // The term of our goal should be fully unconstrained, so this should never fail.
+                //
+                // It can however be ambiguous when the resolved type is a projection.
+                let nested_goals = ecx
+                    .infcx
+                    .eq(goal.param_env, goal.predicate.term, assumption_projection_pred.term)
+                    .expect("failed to unify with unconstrained term");
+                let rhs_certainty = ecx
+                    .evaluate_all(nested_goals)
+                    .expect("failed to unify with unconstrained term");
+
+                ecx.make_canonical_response(subst_certainty.unify_and(rhs_certainty))
+            })
+        } else {
+            Err(NoSolution)
+        }
+    }
+
+    fn consider_auto_trait_candidate(
+        _ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        bug!("auto traits do not have associated types: {:?}", goal);
+    }
+
+    fn consider_trait_alias_candidate(
+        _ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        bug!("trait aliases do not have associated types: {:?}", goal);
+    }
+
+    fn consider_builtin_sized_candidate(
+        _ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        bug!("`Sized` does not have an associated type: {:?}", goal);
+    }
+
+    fn consider_builtin_copy_clone_candidate(
+        _ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        bug!("`Copy`/`Clone` does not have an associated type: {:?}", goal);
+    }
+
+    fn consider_builtin_pointer_sized_candidate(
+        _ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        bug!("`PointerSized` does not have an associated type: {:?}", goal);
+    }
+
+    fn consider_builtin_fn_trait_candidates(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+        goal_kind: ty::ClosureKind,
+    ) -> QueryResult<'tcx> {
+        if let Some(tupled_inputs_and_output) =
+            structural_traits::extract_tupled_inputs_and_output_from_callable(
+                ecx.tcx(),
+                goal.predicate.self_ty(),
+                goal_kind,
+            )?
+        {
+            let pred = tupled_inputs_and_output
+                .map_bound(|(inputs, output)| ty::ProjectionPredicate {
+                    projection_ty: ecx
+                        .tcx()
+                        .mk_alias_ty(goal.predicate.def_id(), [goal.predicate.self_ty(), inputs]),
+                    term: output.into(),
+                })
+                .to_predicate(ecx.tcx());
+            Self::consider_assumption(ecx, goal, pred)
+        } else {
+            ecx.make_canonical_response(Certainty::AMBIGUOUS)
+        }
+    }
+
+    fn consider_builtin_tuple_candidate(
+        _ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        bug!("`Tuple` does not have an associated type: {:?}", goal);
+    }
 }
 
 /// This behavior is also implemented in `rustc_ty_utils` and in the old `project` code.
@@ -224,10 +404,9 @@ fn fetch_eligible_assoc_item_def<'tcx>(
     goal_trait_ref: ty::TraitRef<'tcx>,
     trait_assoc_def_id: DefId,
     impl_def_id: DefId,
-) -> Option<LeafDef> {
+) -> Result<Option<LeafDef>, NoSolution> {
     let node_item = specialization_graph::assoc_def(infcx.tcx, impl_def_id, trait_assoc_def_id)
-        .map_err(|ErrorGuaranteed { .. }| ())
-        .ok()?;
+        .map_err(|ErrorGuaranteed { .. }| NoSolution)?;
 
     let eligible = if node_item.is_final() {
         // Non-specializable items are always projectable.
@@ -246,5 +425,5 @@ fn fetch_eligible_assoc_item_def<'tcx>(
         }
     };
 
-    if eligible { Some(node_item) } else { None }
+    if eligible { Ok(Some(node_item)) } else { Ok(None) }
 }
diff --git a/compiler/rustc_trait_selection/src/solve/search_graph/cache.rs b/compiler/rustc_trait_selection/src/solve/search_graph/cache.rs
new file mode 100644
index 00000000000..730a8e61258
--- /dev/null
+++ b/compiler/rustc_trait_selection/src/solve/search_graph/cache.rs
@@ -0,0 +1,123 @@
+//! This module both handles the global cache which stores "finished" goals,
+//! and the provisional cache which contains partially computed goals.
+//!
+//! The provisional cache is necessary when dealing with coinductive cycles.
+//!
+//! For more information about the provisional cache and coinduction in general,
+//! check out the relevant section of the rustc-dev-guide.
+//!
+//! FIXME(@lcnr): Write that section, feel free to ping me if you need help here
+//! before then or if I still haven't done that before January 2023.
+use super::overflow::OverflowData;
+use super::StackDepth;
+use crate::solve::{CanonicalGoal, QueryResult};
+use rustc_data_structures::fx::FxHashMap;
+use rustc_index::vec::IndexVec;
+use rustc_middle::ty::TyCtxt;
+
+rustc_index::newtype_index! {
+    pub struct EntryIndex {}
+}
+
+#[derive(Debug, Clone)]
+pub(super) struct ProvisionalEntry<'tcx> {
+    // In case we have a coinductive cycle, this is the
+    // the currently least restrictive result of this goal.
+    pub(super) response: QueryResult<'tcx>,
+    // In case of a cycle, the position of deepest stack entry involved
+    // in that cycle. This is monotonically decreasing in the stack as all
+    // elements between the current stack element in the deepest stack entry
+    // involved have to also be involved in that cycle.
+    //
+    // We can only move entries to the global cache once we're complete done
+    // with the cycle. If this entry has not been involved in a cycle,
+    // this is just its own depth.
+    pub(super) depth: StackDepth,
+
+    // The goal for this entry. Should always be equal to the corresponding goal
+    // in the lookup table.
+    pub(super) goal: CanonicalGoal<'tcx>,
+}
+
+pub(super) struct ProvisionalCache<'tcx> {
+    pub(super) entries: IndexVec<EntryIndex, ProvisionalEntry<'tcx>>,
+    // FIXME: This is only used to quickly check whether a given goal
+    // is in the cache. We should experiment with using something like
+    // `SsoHashSet` here because in most cases there are only a few entries.
+    pub(super) lookup_table: FxHashMap<CanonicalGoal<'tcx>, EntryIndex>,
+}
+
+impl<'tcx> ProvisionalCache<'tcx> {
+    pub(super) fn empty() -> ProvisionalCache<'tcx> {
+        ProvisionalCache { entries: Default::default(), lookup_table: Default::default() }
+    }
+
+    pub(super) fn is_empty(&self) -> bool {
+        self.entries.is_empty() && self.lookup_table.is_empty()
+    }
+
+    /// Adds a dependency from the current leaf to `target` in the cache
+    /// to prevent us from moving any goals which depend on the current leaf
+    /// to the global cache while we're still computing `target`.
+    ///
+    /// Its important to note that `target` may already be part of a different cycle.
+    /// In this case we have to ensure that we also depend on all other goals
+    /// in the existing cycle in addition to the potentially direct cycle with `target`.
+    pub(super) fn add_dependency_of_leaf_on(&mut self, target: EntryIndex) {
+        let depth = self.entries[target].depth;
+        for provisional_entry in &mut self.entries.raw[target.index()..] {
+            // The depth of `target` is the position of the deepest goal in the stack
+            // on which `target` depends. That goal is the `root` of this cycle.
+            //
+            // Any entry which was added after `target` is either on the stack itself
+            // at which point its depth is definitely at least as high as the depth of
+            // `root`. If it's not on the stack itself it has to depend on a goal
+            // between `root` and `leaf`. If it were to depend on a goal deeper in the
+            // stack than `root`, then `root` would also depend on that goal, at which
+            // point `root` wouldn't be the root anymore.
+            debug_assert!(provisional_entry.depth >= depth);
+            provisional_entry.depth = depth;
+        }
+
+        // We only update entries which were added after `target` as no other
+        // entry should have a higher depth.
+        //
+        // Any entry which previously had a higher depth than target has to
+        // be between `target` and `root`. Because of this we would have updated
+        // its depth when calling `add_dependency_of_leaf_on(root)` for `target`.
+        if cfg!(debug_assertions) {
+            self.entries.iter().all(|e| e.depth <= depth);
+        }
+    }
+
+    pub(super) fn depth(&self, entry_index: EntryIndex) -> StackDepth {
+        self.entries[entry_index].depth
+    }
+
+    pub(super) fn provisional_result(&self, entry_index: EntryIndex) -> QueryResult<'tcx> {
+        self.entries[entry_index].response.clone()
+    }
+}
+
+pub(super) fn try_move_finished_goal_to_global_cache<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    overflow_data: &mut OverflowData,
+    stack: &IndexVec<super::StackDepth, super::StackElem<'tcx>>,
+    goal: CanonicalGoal<'tcx>,
+    response: QueryResult<'tcx>,
+) {
+    // We move goals to the global cache if we either did not hit an overflow or if it's
+    // the root goal as that will now always hit the same overflow limit.
+    //
+    // NOTE: We cannot move any non-root goals to the global cache even if their final result
+    // isn't impacted by the overflow as that goal still has unstable query dependencies
+    // because it didn't go its full depth.
+    //
+    // FIXME(@lcnr): We could still cache subtrees which are not impacted by overflow though.
+    // Tracking that info correctly isn't trivial, so I haven't implemented it for now.
+    let should_cache_globally = !overflow_data.did_overflow() || stack.is_empty();
+    if should_cache_globally {
+        // FIXME: move the provisional entry to the global cache.
+        let _ = (tcx, goal, response);
+    }
+}
diff --git a/compiler/rustc_trait_selection/src/solve/search_graph/mod.rs b/compiler/rustc_trait_selection/src/solve/search_graph/mod.rs
new file mode 100644
index 00000000000..0030e9aa3e5
--- /dev/null
+++ b/compiler/rustc_trait_selection/src/solve/search_graph/mod.rs
@@ -0,0 +1,178 @@
+mod cache;
+mod overflow;
+
+use self::cache::ProvisionalEntry;
+use super::{CanonicalGoal, Certainty, MaybeCause, QueryResult};
+use cache::ProvisionalCache;
+use overflow::OverflowData;
+use rustc_index::vec::IndexVec;
+use rustc_middle::ty::TyCtxt;
+use std::collections::hash_map::Entry;
+
+rustc_index::newtype_index! {
+    pub struct StackDepth {}
+}
+
+struct StackElem<'tcx> {
+    goal: CanonicalGoal<'tcx>,
+    has_been_used: bool,
+}
+
+pub(super) struct SearchGraph<'tcx> {
+    /// The stack of goals currently being computed.
+    ///
+    /// An element is *deeper* in the stack if its index is *lower*.
+    stack: IndexVec<StackDepth, StackElem<'tcx>>,
+    overflow_data: OverflowData,
+    provisional_cache: ProvisionalCache<'tcx>,
+}
+
+impl<'tcx> SearchGraph<'tcx> {
+    pub(super) fn new(tcx: TyCtxt<'tcx>) -> SearchGraph<'tcx> {
+        Self {
+            stack: Default::default(),
+            overflow_data: OverflowData::new(tcx),
+            provisional_cache: ProvisionalCache::empty(),
+        }
+    }
+
+    pub(super) fn is_empty(&self) -> bool {
+        self.stack.is_empty()
+            && self.provisional_cache.is_empty()
+            && !self.overflow_data.did_overflow()
+    }
+
+    /// Tries putting the new goal on the stack, returning an error if it is already cached.
+    ///
+    /// This correctly updates the provisional cache if there is a cycle.
+    pub(super) fn try_push_stack(
+        &mut self,
+        tcx: TyCtxt<'tcx>,
+        goal: CanonicalGoal<'tcx>,
+    ) -> Result<(), QueryResult<'tcx>> {
+        // FIXME: start by checking the global cache
+
+        // Look at the provisional cache to check for cycles.
+        let cache = &mut self.provisional_cache;
+        match cache.lookup_table.entry(goal) {
+            // No entry, simply push this goal on the stack after dealing with overflow.
+            Entry::Vacant(v) => {
+                if self.overflow_data.has_overflow(self.stack.len()) {
+                    return Err(self.deal_with_overflow(tcx, goal));
+                }
+
+                let depth = self.stack.push(StackElem { goal, has_been_used: false });
+                let response = super::response_no_constraints(tcx, goal, Certainty::Yes);
+                let entry_index = cache.entries.push(ProvisionalEntry { response, depth, goal });
+                v.insert(entry_index);
+                Ok(())
+            }
+            // We have a nested goal which relies on a goal `root` deeper in the stack.
+            //
+            // We first store that we may have to rerun `evaluate_goal` for `root` in case the
+            // provisional response is not equal to the final response. We also update the depth
+            // of all goals which recursively depend on our current goal to depend on `root`
+            // instead.
+            //
+            // Finally we can return either the provisional response for that goal if we have a
+            // coinductive cycle or an ambiguous result if the cycle is inductive.
+            Entry::Occupied(entry_index) => {
+                let entry_index = *entry_index.get();
+
+                cache.add_dependency_of_leaf_on(entry_index);
+                let stack_depth = cache.depth(entry_index);
+
+                self.stack[stack_depth].has_been_used = true;
+                // NOTE: The goals on the stack aren't the only goals involved in this cycle.
+                // We can also depend on goals which aren't part of the stack but coinductively
+                // depend on the stack themselves. We already checked whether all the goals
+                // between these goals and their root on the stack. This means that as long as
+                // each goal in a cycle is checked for coinductivity by itself, simply checking
+                // the stack is enough.
+                if self.stack.raw[stack_depth.index()..]
+                    .iter()
+                    .all(|g| g.goal.value.predicate.is_coinductive(tcx))
+                {
+                    Err(cache.provisional_result(entry_index))
+                } else {
+                    Err(super::response_no_constraints(
+                        tcx,
+                        goal,
+                        Certainty::Maybe(MaybeCause::Overflow),
+                    ))
+                }
+            }
+        }
+    }
+
+    /// We cannot simply store the result of [super::EvalCtxt::compute_goal] as we have to deal with
+    /// coinductive cycles.
+    ///
+    /// When we encounter a coinductive cycle, we have to prove the final result of that cycle
+    /// while we are still computing that result. Because of this we continously recompute the
+    /// cycle until the result of the previous iteration is equal to the final result, at which
+    /// point we are done.
+    ///
+    /// This function returns `true` if we were able to finalize the goal and `false` if it has
+    /// updated the provisional cache and we have to recompute the current goal.
+    ///
+    /// FIXME: Refer to the rustc-dev-guide entry once it exists.
+    pub(super) fn try_finalize_goal(
+        &mut self,
+        tcx: TyCtxt<'tcx>,
+        actual_goal: CanonicalGoal<'tcx>,
+        response: QueryResult<'tcx>,
+    ) -> bool {
+        let StackElem { goal, has_been_used } = self.stack.pop().unwrap();
+        assert_eq!(goal, actual_goal);
+
+        let cache = &mut self.provisional_cache;
+        let provisional_entry_index = *cache.lookup_table.get(&goal).unwrap();
+        let provisional_entry = &mut cache.entries[provisional_entry_index];
+        let depth = provisional_entry.depth;
+        // Was the current goal the root of a cycle and was the provisional response
+        // different from the final one.
+        if has_been_used && provisional_entry.response != response {
+            // If so, update the provisional reponse for this goal...
+            provisional_entry.response = response;
+            // ...remove all entries whose result depends on this goal
+            // from the provisional cache...
+            //
+            // That's not completely correct, as a nested goal can also
+            // depend on a goal which is lower in the stack so it doesn't
+            // actually depend on the current goal. This should be fairly
+            // rare and is hopefully not relevant for performance.
+            #[allow(rustc::potential_query_instability)]
+            cache.lookup_table.retain(|_key, index| *index <= provisional_entry_index);
+            cache.entries.truncate(provisional_entry_index.index() + 1);
+
+            // ...and finally push our goal back on the stack and reevaluate it.
+            self.stack.push(StackElem { goal, has_been_used: false });
+            false
+        } else {
+            // If not, we're done with this goal.
+            //
+            // Check whether that this goal doesn't depend on a goal deeper on the stack
+            // and if so, move it and all nested goals to the global cache.
+            //
+            // Note that if any nested goal were to depend on something deeper on the stack,
+            // this would have also updated the depth of the current goal.
+            if depth == self.stack.next_index() {
+                for (i, entry) in cache.entries.drain_enumerated(provisional_entry_index.index()..)
+                {
+                    let actual_index = cache.lookup_table.remove(&entry.goal);
+                    debug_assert_eq!(Some(i), actual_index);
+                    debug_assert!(entry.depth == depth);
+                    cache::try_move_finished_goal_to_global_cache(
+                        tcx,
+                        &mut self.overflow_data,
+                        &self.stack,
+                        entry.goal,
+                        entry.response,
+                    );
+                }
+            }
+            true
+        }
+    }
+}
diff --git a/compiler/rustc_trait_selection/src/solve/overflow.rs b/compiler/rustc_trait_selection/src/solve/search_graph/overflow.rs
index 8bbb9f63e78..1dd3894c91a 100644
--- a/compiler/rustc_trait_selection/src/solve/overflow.rs
+++ b/compiler/rustc_trait_selection/src/solve/search_graph/overflow.rs
@@ -3,8 +3,8 @@ use rustc_infer::traits::query::NoSolution;
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Limit;
 
-use super::cache::response_no_constraints;
-use super::{Certainty, EvalCtxt, MaybeCause, QueryResult};
+use super::SearchGraph;
+use crate::solve::{response_no_constraints, Certainty, EvalCtxt, MaybeCause, QueryResult};
 
 /// When detecting a solver overflow, we return ambiguity. Overflow can be
 /// *hidden* by either a fatal error in an **AND** or a trivial success in an **OR**.
@@ -50,32 +50,35 @@ impl OverflowData {
     }
 }
 
-impl<'tcx> EvalCtxt<'tcx> {
-    pub(super) fn deal_with_overflow(
+impl<'tcx> SearchGraph<'tcx> {
+    pub fn deal_with_overflow(
         &mut self,
+        tcx: TyCtxt<'tcx>,
         goal: Canonical<'tcx, impl Sized>,
     ) -> QueryResult<'tcx> {
         self.overflow_data.deal_with_overflow();
-        response_no_constraints(self.tcx, goal, Certainty::Maybe(MaybeCause::Overflow))
+        response_no_constraints(tcx, goal, Certainty::Maybe(MaybeCause::Overflow))
     }
+}
 
+impl<'tcx> EvalCtxt<'_, 'tcx> {
     /// A `while`-loop which tracks overflow.
-    pub(super) fn repeat_while_none(
+    pub fn repeat_while_none(
         &mut self,
         mut loop_body: impl FnMut(&mut Self) -> Option<Result<Certainty, NoSolution>>,
     ) -> Result<Certainty, NoSolution> {
-        let start_depth = self.overflow_data.additional_depth;
-        let depth = self.provisional_cache.current_depth();
-        while !self.overflow_data.has_overflow(depth) {
+        let start_depth = self.search_graph.overflow_data.additional_depth;
+        let depth = self.search_graph.stack.len();
+        while !self.search_graph.overflow_data.has_overflow(depth) {
             if let Some(result) = loop_body(self) {
-                self.overflow_data.additional_depth = start_depth;
+                self.search_graph.overflow_data.additional_depth = start_depth;
                 return result;
             }
 
-            self.overflow_data.additional_depth += 1;
+            self.search_graph.overflow_data.additional_depth += 1;
         }
-        self.overflow_data.additional_depth = start_depth;
-        self.overflow_data.deal_with_overflow();
+        self.search_graph.overflow_data.additional_depth = start_depth;
+        self.search_graph.overflow_data.deal_with_overflow();
         Ok(Certainty::Maybe(MaybeCause::Overflow))
     }
 }
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals.rs b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
index a43fef5cdb0..4b6d673c999 100644
--- a/compiler/rustc_trait_selection/src/solve/trait_goals.rs
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals.rs
@@ -2,58 +2,20 @@
 
 use std::iter;
 
-use super::assembly::{self, AssemblyCtxt};
-use super::{CanonicalGoal, EvalCtxt, Goal, QueryResult};
+use super::assembly::{self, Candidate, CandidateSource};
+use super::infcx_ext::InferCtxtExt;
+use super::{Certainty, EvalCtxt, Goal, QueryResult};
 use rustc_hir::def_id::DefId;
-use rustc_infer::infer::InferOk;
+use rustc_infer::infer::InferCtxt;
 use rustc_infer::traits::query::NoSolution;
-use rustc_infer::traits::ObligationCause;
 use rustc_middle::ty::fast_reject::{DeepRejectCtxt, TreatParams};
-use rustc_middle::ty::TraitPredicate;
-use rustc_middle::ty::{self, Ty, TyCtxt};
+use rustc_middle::ty::{self, ToPredicate, Ty, TyCtxt};
+use rustc_middle::ty::{TraitPredicate, TypeVisitable};
 use rustc_span::DUMMY_SP;
 
-#[allow(dead_code)] // FIXME: implement and use all variants.
-#[derive(Debug, Clone, Copy)]
-pub(super) enum CandidateSource {
-    /// Some user-defined impl with the given `DefId`.
-    Impl(DefId),
-    /// The n-th caller bound in the `param_env` of our goal.
-    ///
-    /// This is pretty much always a bound from the `where`-clauses of the
-    /// currently checked item.
-    ParamEnv(usize),
-    /// A bound on the `self_ty` in case it is a projection or an opaque type.
-    ///
-    /// # Examples
-    ///
-    /// ```ignore (for syntax highlighting)
-    /// trait Trait {
-    ///     type Assoc: OtherTrait;
-    /// }
-    /// ```
-    ///
-    /// We know that `<Whatever as Trait>::Assoc: OtherTrait` holds by looking at
-    /// the bounds on `Trait::Assoc`.
-    AliasBound(usize),
-    /// A builtin implementation for some specific traits, used in cases
-    /// where we cannot rely an ordinary library implementations.
-    ///
-    /// The most notable examples are `Sized`, `Copy` and `Clone`. This is also
-    /// used for the `DiscriminantKind` and `Pointee` trait, both of which have
-    /// an associated type.
-    Builtin,
-    /// An automatic impl for an auto trait, e.g. `Send`. These impls recursively look
-    /// at the constituent types of the `self_ty` to check whether the auto trait
-    /// is implemented for those.
-    AutoImpl,
-}
-
-type Candidate<'tcx> = assembly::Candidate<'tcx, TraitPredicate<'tcx>>;
+pub mod structural_traits;
 
 impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
-    type CandidateSource = CandidateSource;
-
     fn self_ty(self) -> Ty<'tcx> {
         self.self_ty()
     }
@@ -67,55 +29,194 @@ impl<'tcx> assembly::GoalKind<'tcx> for TraitPredicate<'tcx> {
     }
 
     fn consider_impl_candidate(
-        acx: &mut AssemblyCtxt<'_, 'tcx, Self>,
+        ecx: &mut EvalCtxt<'_, 'tcx>,
         goal: Goal<'tcx, TraitPredicate<'tcx>>,
         impl_def_id: DefId,
-    ) {
-        let tcx = acx.cx.tcx;
+    ) -> QueryResult<'tcx> {
+        let tcx = ecx.tcx();
 
         let impl_trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap();
         let drcx = DeepRejectCtxt { treat_obligation_params: TreatParams::AsPlaceholder };
         if iter::zip(goal.predicate.trait_ref.substs, impl_trait_ref.skip_binder().substs)
             .any(|(goal, imp)| !drcx.generic_args_may_unify(goal, imp))
         {
-            return;
+            return Err(NoSolution);
         }
 
-        acx.infcx.probe(|_| {
-            let impl_substs = acx.infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id);
+        ecx.infcx.probe(|_| {
+            let impl_substs = ecx.infcx.fresh_substs_for_item(DUMMY_SP, impl_def_id);
             let impl_trait_ref = impl_trait_ref.subst(tcx, impl_substs);
 
-            let Ok(InferOk { obligations, .. }) = acx
-                .infcx
-                .at(&ObligationCause::dummy(), goal.param_env)
-                .define_opaque_types(false)
-                .eq(goal.predicate.trait_ref, impl_trait_ref)
-                .map_err(|e| debug!("failed to equate trait refs: {e:?}"))
-            else {
-                return
-            };
+            let mut nested_goals =
+                ecx.infcx.eq(goal.param_env, goal.predicate.trait_ref, impl_trait_ref)?;
             let where_clause_bounds = tcx
                 .predicates_of(impl_def_id)
                 .instantiate(tcx, impl_substs)
                 .predicates
                 .into_iter()
                 .map(|pred| goal.with(tcx, pred));
+            nested_goals.extend(where_clause_bounds);
+            ecx.evaluate_all_and_make_canonical_response(nested_goals)
+        })
+    }
+
+    fn consider_assumption(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+        assumption: ty::Predicate<'tcx>,
+    ) -> QueryResult<'tcx> {
+        if let Some(poly_trait_pred) = assumption.to_opt_poly_trait_pred() {
+            // FIXME: Constness and polarity
+            ecx.infcx.probe(|_| {
+                let assumption_trait_pred =
+                    ecx.infcx.instantiate_bound_vars_with_infer(poly_trait_pred);
+                let nested_goals = ecx.infcx.eq(
+                    goal.param_env,
+                    goal.predicate.trait_ref,
+                    assumption_trait_pred.trait_ref,
+                )?;
+                ecx.evaluate_all_and_make_canonical_response(nested_goals)
+            })
+        } else {
+            Err(NoSolution)
+        }
+    }
+
+    fn consider_auto_trait_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        ecx.probe_and_evaluate_goal_for_constituent_tys(
+            goal,
+            structural_traits::instantiate_constituent_tys_for_auto_trait,
+        )
+    }
 
-            let nested_goals =
-                obligations.into_iter().map(|o| o.into()).chain(where_clause_bounds).collect();
+    fn consider_trait_alias_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        let tcx = ecx.tcx();
 
-            let Ok(certainty) = acx.cx.evaluate_all(acx.infcx, nested_goals) else { return };
-            acx.try_insert_candidate(CandidateSource::Impl(impl_def_id), certainty);
+        ecx.infcx.probe(|_| {
+            let nested_obligations = tcx
+                .predicates_of(goal.predicate.def_id())
+                .instantiate(tcx, goal.predicate.trait_ref.substs);
+            ecx.evaluate_all_and_make_canonical_response(
+                nested_obligations.predicates.into_iter().map(|p| goal.with(tcx, p)).collect(),
+            )
         })
     }
+
+    fn consider_builtin_sized_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        ecx.probe_and_evaluate_goal_for_constituent_tys(
+            goal,
+            structural_traits::instantiate_constituent_tys_for_sized_trait,
+        )
+    }
+
+    fn consider_builtin_copy_clone_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        ecx.probe_and_evaluate_goal_for_constituent_tys(
+            goal,
+            structural_traits::instantiate_constituent_tys_for_copy_clone_trait,
+        )
+    }
+
+    fn consider_builtin_pointer_sized_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        if goal.predicate.self_ty().has_non_region_infer() {
+            return ecx.make_canonical_response(Certainty::AMBIGUOUS);
+        }
+
+        let tcx = ecx.tcx();
+        let self_ty = tcx.erase_regions(goal.predicate.self_ty());
+
+        if let Ok(layout) = tcx.layout_of(goal.param_env.and(self_ty))
+            &&  let usize_layout = tcx.layout_of(ty::ParamEnv::empty().and(tcx.types.usize)).unwrap().layout
+            && layout.layout.size() == usize_layout.size()
+            && layout.layout.align().abi == usize_layout.align().abi
+        {
+            // FIXME: We could make this faster by making a no-constraints response
+            ecx.make_canonical_response(Certainty::Yes)
+        } else {
+            Err(NoSolution)
+        }
+    }
+
+    fn consider_builtin_fn_trait_candidates(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+        goal_kind: ty::ClosureKind,
+    ) -> QueryResult<'tcx> {
+        if let Some(tupled_inputs_and_output) =
+            structural_traits::extract_tupled_inputs_and_output_from_callable(
+                ecx.tcx(),
+                goal.predicate.self_ty(),
+                goal_kind,
+            )?
+        {
+            let pred = tupled_inputs_and_output
+                .map_bound(|(inputs, _)| {
+                    ecx.tcx()
+                        .mk_trait_ref(goal.predicate.def_id(), [goal.predicate.self_ty(), inputs])
+                })
+                .to_predicate(ecx.tcx());
+            Self::consider_assumption(ecx, goal, pred)
+        } else {
+            ecx.make_canonical_response(Certainty::AMBIGUOUS)
+        }
+    }
+
+    fn consider_builtin_tuple_candidate(
+        ecx: &mut EvalCtxt<'_, 'tcx>,
+        goal: Goal<'tcx, Self>,
+    ) -> QueryResult<'tcx> {
+        if let ty::Tuple(..) = goal.predicate.self_ty().kind() {
+            ecx.make_canonical_response(Certainty::Yes)
+        } else {
+            Err(NoSolution)
+        }
+    }
 }
 
-impl<'tcx> EvalCtxt<'tcx> {
+impl<'tcx> EvalCtxt<'_, 'tcx> {
+    /// Convenience function for traits that are structural, i.e. that only
+    /// have nested subgoals that only change the self type. Unlike other
+    /// evaluate-like helpers, this does a probe, so it doesn't need to be
+    /// wrapped in one.
+    fn probe_and_evaluate_goal_for_constituent_tys(
+        &mut self,
+        goal: Goal<'tcx, TraitPredicate<'tcx>>,
+        constituent_tys: impl Fn(&InferCtxt<'tcx>, Ty<'tcx>) -> Result<Vec<Ty<'tcx>>, NoSolution>,
+    ) -> QueryResult<'tcx> {
+        self.infcx.probe(|_| {
+            self.evaluate_all_and_make_canonical_response(
+                constituent_tys(self.infcx, goal.predicate.self_ty())?
+                    .into_iter()
+                    .map(|ty| {
+                        goal.with(
+                            self.tcx(),
+                            ty::Binder::dummy(goal.predicate.with_self_ty(self.tcx(), ty)),
+                        )
+                    })
+                    .collect(),
+            )
+        })
+    }
+
     pub(super) fn compute_trait_goal(
         &mut self,
-        goal: CanonicalGoal<'tcx, TraitPredicate<'tcx>>,
+        goal: Goal<'tcx, TraitPredicate<'tcx>>,
     ) -> QueryResult<'tcx> {
-        let candidates = AssemblyCtxt::assemble_and_evaluate_candidates(self, goal);
+        let candidates = self.assemble_and_evaluate_candidates(goal);
         self.merge_trait_candidates_discard_reservation_impls(candidates)
     }
 
@@ -169,14 +270,13 @@ impl<'tcx> EvalCtxt<'tcx> {
             (CandidateSource::Impl(_), _)
             | (CandidateSource::ParamEnv(_), _)
             | (CandidateSource::AliasBound(_), _)
-            | (CandidateSource::Builtin, _)
-            | (CandidateSource::AutoImpl, _) => unimplemented!(),
+            | (CandidateSource::BuiltinImpl, _) => unimplemented!(),
         }
     }
 
     fn discard_reservation_impl(&self, candidate: Candidate<'tcx>) -> Candidate<'tcx> {
         if let CandidateSource::Impl(def_id) = candidate.source {
-            if let ty::ImplPolarity::Reservation = self.tcx.impl_polarity(def_id) {
+            if let ty::ImplPolarity::Reservation = self.tcx().impl_polarity(def_id) {
                 debug!("Selected reservation impl");
                 // FIXME: reduce candidate to ambiguous
                 // FIXME: replace `var_values` with identity, yeet external constraints.
diff --git a/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs b/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs
new file mode 100644
index 00000000000..a11cd13cb08
--- /dev/null
+++ b/compiler/rustc_trait_selection/src/solve/trait_goals/structural_traits.rs
@@ -0,0 +1,223 @@
+use rustc_hir::{Movability, Mutability};
+use rustc_infer::{infer::InferCtxt, traits::query::NoSolution};
+use rustc_middle::ty::{self, Ty, TyCtxt};
+
+// Calculates the constituent types of a type for `auto trait` purposes.
+//
+// For types with an "existential" binder, i.e. generator witnesses, we also
+// instantiate the binder with placeholders eagerly.
+pub(super) fn instantiate_constituent_tys_for_auto_trait<'tcx>(
+    infcx: &InferCtxt<'tcx>,
+    ty: Ty<'tcx>,
+) -> Result<Vec<Ty<'tcx>>, NoSolution> {
+    let tcx = infcx.tcx;
+    match *ty.kind() {
+        ty::Uint(_)
+        | ty::Int(_)
+        | ty::Bool
+        | ty::Float(_)
+        | ty::FnDef(..)
+        | ty::FnPtr(_)
+        | ty::Str
+        | ty::Error(_)
+        | ty::Infer(ty::IntVar(_) | ty::FloatVar(_))
+        | ty::Never
+        | ty::Char => Ok(vec![]),
+
+        ty::Placeholder(..)
+        | ty::Dynamic(..)
+        | ty::Param(..)
+        | ty::Foreign(..)
+        | ty::Alias(ty::Projection, ..)
+        | ty::Bound(..)
+        | ty::Infer(ty::TyVar(_)) => Err(NoSolution),
+
+        ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => bug!(),
+
+        ty::RawPtr(ty::TypeAndMut { ty: element_ty, .. }) | ty::Ref(_, element_ty, _) => {
+            Ok(vec![element_ty])
+        }
+
+        ty::Array(element_ty, _) | ty::Slice(element_ty) => Ok(vec![element_ty]),
+
+        ty::Tuple(ref tys) => {
+            // (T1, ..., Tn) -- meets any bound that all of T1...Tn meet
+            Ok(tys.iter().collect())
+        }
+
+        ty::Closure(_, ref substs) => Ok(vec![substs.as_closure().tupled_upvars_ty()]),
+
+        ty::Generator(_, ref substs, _) => {
+            let generator_substs = substs.as_generator();
+            Ok(vec![generator_substs.tupled_upvars_ty(), generator_substs.witness()])
+        }
+
+        ty::GeneratorWitness(types) => {
+            Ok(infcx.replace_bound_vars_with_placeholders(types).to_vec())
+        }
+
+        // For `PhantomData<T>`, we pass `T`.
+        ty::Adt(def, substs) if def.is_phantom_data() => Ok(vec![substs.type_at(0)]),
+
+        ty::Adt(def, substs) => Ok(def.all_fields().map(|f| f.ty(tcx, substs)).collect()),
+
+        ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
+            // We can resolve the `impl Trait` to its concrete type,
+            // which enforces a DAG between the functions requiring
+            // the auto trait bounds in question.
+            Ok(vec![tcx.bound_type_of(def_id).subst(tcx, substs)])
+        }
+    }
+}
+
+pub(super) fn instantiate_constituent_tys_for_sized_trait<'tcx>(
+    infcx: &InferCtxt<'tcx>,
+    ty: Ty<'tcx>,
+) -> Result<Vec<Ty<'tcx>>, NoSolution> {
+    match *ty.kind() {
+        ty::Infer(ty::IntVar(_) | ty::FloatVar(_))
+        | ty::Uint(_)
+        | ty::Int(_)
+        | ty::Bool
+        | ty::Float(_)
+        | ty::FnDef(..)
+        | ty::FnPtr(_)
+        | ty::RawPtr(..)
+        | ty::Char
+        | ty::Ref(..)
+        | ty::Generator(..)
+        | ty::GeneratorWitness(..)
+        | ty::Array(..)
+        | ty::Closure(..)
+        | ty::Never
+        | ty::Dynamic(_, _, ty::DynStar)
+        | ty::Error(_) => Ok(vec![]),
+
+        ty::Str
+        | ty::Slice(_)
+        | ty::Dynamic(..)
+        | ty::Foreign(..)
+        | ty::Alias(..)
+        | ty::Param(_)
+        | ty::Infer(ty::TyVar(_)) => Err(NoSolution),
+
+        ty::Placeholder(..)
+        | ty::Bound(..)
+        | ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => bug!(),
+
+        ty::Tuple(tys) => Ok(tys.to_vec()),
+
+        ty::Adt(def, substs) => {
+            let sized_crit = def.sized_constraint(infcx.tcx);
+            Ok(sized_crit
+                .0
+                .iter()
+                .map(|ty| sized_crit.rebind(*ty).subst(infcx.tcx, substs))
+                .collect())
+        }
+    }
+}
+
+pub(super) fn instantiate_constituent_tys_for_copy_clone_trait<'tcx>(
+    infcx: &InferCtxt<'tcx>,
+    ty: Ty<'tcx>,
+) -> Result<Vec<Ty<'tcx>>, NoSolution> {
+    match *ty.kind() {
+        ty::Infer(ty::IntVar(_) | ty::FloatVar(_))
+        | ty::FnDef(..)
+        | ty::FnPtr(_)
+        | ty::Error(_) => Ok(vec![]),
+
+        // Implementations are provided in core
+        ty::Uint(_)
+        | ty::Int(_)
+        | ty::Bool
+        | ty::Float(_)
+        | ty::Char
+        | ty::RawPtr(..)
+        | ty::Never
+        | ty::Ref(_, _, Mutability::Not)
+        | ty::Array(..) => Err(NoSolution),
+
+        ty::Dynamic(..)
+        | ty::Str
+        | ty::Slice(_)
+        | ty::Generator(_, _, Movability::Static)
+        | ty::Foreign(..)
+        | ty::Ref(_, _, Mutability::Mut)
+        | ty::Adt(_, _)
+        | ty::Alias(_, _)
+        | ty::Param(_)
+        | ty::Infer(ty::TyVar(_)) => Err(NoSolution),
+
+        ty::Placeholder(..)
+        | ty::Bound(..)
+        | ty::Infer(ty::FreshTy(_) | ty::FreshIntTy(_) | ty::FreshFloatTy(_)) => bug!(),
+
+        ty::Tuple(tys) => Ok(tys.to_vec()),
+
+        ty::Closure(_, substs) => Ok(vec![substs.as_closure().tupled_upvars_ty()]),
+
+        ty::Generator(_, substs, Movability::Movable) => {
+            if infcx.tcx.features().generator_clone {
+                let generator = substs.as_generator();
+                Ok(vec![generator.tupled_upvars_ty(), generator.witness()])
+            } else {
+                Err(NoSolution)
+            }
+        }
+
+        ty::GeneratorWitness(types) => {
+            Ok(infcx.replace_bound_vars_with_placeholders(types).to_vec())
+        }
+    }
+}
+
+pub(crate) fn extract_tupled_inputs_and_output_from_callable<'tcx>(
+    tcx: TyCtxt<'tcx>,
+    self_ty: Ty<'tcx>,
+    goal_kind: ty::ClosureKind,
+) -> Result<Option<ty::Binder<'tcx, (Ty<'tcx>, Ty<'tcx>)>>, NoSolution> {
+    match *self_ty.kind() {
+        ty::FnDef(def_id, substs) => Ok(Some(
+            tcx.bound_fn_sig(def_id)
+                .subst(tcx, substs)
+                .map_bound(|sig| (tcx.mk_tup(sig.inputs().iter()), sig.output())),
+        )),
+        ty::FnPtr(sig) => {
+            Ok(Some(sig.map_bound(|sig| (tcx.mk_tup(sig.inputs().iter()), sig.output()))))
+        }
+        ty::Closure(_, substs) => {
+            let closure_substs = substs.as_closure();
+            match closure_substs.kind_ty().to_opt_closure_kind() {
+                Some(closure_kind) if closure_kind.extends(goal_kind) => {}
+                None => return Ok(None),
+                _ => return Err(NoSolution),
+            }
+            Ok(Some(closure_substs.sig().map_bound(|sig| (sig.inputs()[0], sig.output()))))
+        }
+        ty::Bool
+        | ty::Char
+        | ty::Int(_)
+        | ty::Uint(_)
+        | ty::Float(_)
+        | ty::Adt(_, _)
+        | ty::Foreign(_)
+        | ty::Str
+        | ty::Array(_, _)
+        | ty::Slice(_)
+        | ty::RawPtr(_)
+        | ty::Ref(_, _, _)
+        | ty::Dynamic(_, _, _)
+        | ty::Generator(_, _, _)
+        | ty::GeneratorWitness(_)
+        | ty::Never
+        | ty::Tuple(_)
+        | ty::Alias(_, _)
+        | ty::Param(_)
+        | ty::Placeholder(_)
+        | ty::Bound(_, _)
+        | ty::Infer(_)
+        | ty::Error(_) => Err(NoSolution),
+    }
+}
diff --git a/compiler/rustc_trait_selection/src/traits/coherence.rs b/compiler/rustc_trait_selection/src/traits/coherence.rs
index 0edae34190c..225c1050c7c 100644
--- a/compiler/rustc_trait_selection/src/traits/coherence.rs
+++ b/compiler/rustc_trait_selection/src/traits/coherence.rs
@@ -401,12 +401,12 @@ fn resolve_negative_obligation<'tcx>(
     infcx.resolve_regions(&outlives_env).is_empty()
 }
 
+#[instrument(level = "debug", skip(tcx), ret)]
 pub fn trait_ref_is_knowable<'tcx>(
     tcx: TyCtxt<'tcx>,
     trait_ref: ty::TraitRef<'tcx>,
 ) -> Result<(), Conflict> {
-    debug!("trait_ref_is_knowable(trait_ref={:?})", trait_ref);
-    if orphan_check_trait_ref(tcx, trait_ref, InCrate::Remote).is_ok() {
+    if orphan_check_trait_ref(trait_ref, InCrate::Remote).is_ok() {
         // A downstream or cousin crate is allowed to implement some
         // substitution of this trait-ref.
         return Err(Conflict::Downstream);
@@ -429,11 +429,9 @@ pub fn trait_ref_is_knowable<'tcx>(
     // and if we are an intermediate owner, then we don't care
     // about future-compatibility, which means that we're OK if
     // we are an owner.
-    if orphan_check_trait_ref(tcx, trait_ref, InCrate::Local).is_ok() {
-        debug!("trait_ref_is_knowable: orphan check passed");
+    if orphan_check_trait_ref(trait_ref, InCrate::Local).is_ok() {
         Ok(())
     } else {
-        debug!("trait_ref_is_knowable: nonlocal, nonfundamental, unowned");
         Err(Conflict::Upstream)
     }
 }
@@ -445,6 +443,7 @@ pub fn trait_ref_is_local_or_fundamental<'tcx>(
     trait_ref.def_id.krate == LOCAL_CRATE || tcx.has_attr(trait_ref.def_id, sym::fundamental)
 }
 
+#[derive(Debug)]
 pub enum OrphanCheckErr<'tcx> {
     NonLocalInputType(Vec<(Ty<'tcx>, bool /* Is this the first input type? */)>),
     UncoveredTy(Ty<'tcx>, Option<Ty<'tcx>>),
@@ -456,13 +455,12 @@ pub enum OrphanCheckErr<'tcx> {
 ///
 /// 1. All type parameters in `Self` must be "covered" by some local type constructor.
 /// 2. Some local type must appear in `Self`.
+#[instrument(level = "debug", skip(tcx), ret)]
 pub fn orphan_check(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Result<(), OrphanCheckErr<'_>> {
-    debug!("orphan_check({:?})", impl_def_id);
-
     // We only except this routine to be invoked on implementations
     // of a trait, not inherent implementations.
     let trait_ref = tcx.impl_trait_ref(impl_def_id).unwrap().subst_identity();
-    debug!("orphan_check: trait_ref={:?}", trait_ref);
+    debug!(?trait_ref);
 
     // If the *trait* is local to the crate, ok.
     if trait_ref.def_id.is_local() {
@@ -470,7 +468,7 @@ pub fn orphan_check(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Result<(), OrphanChe
         return Ok(());
     }
 
-    orphan_check_trait_ref(tcx, trait_ref, InCrate::Local)
+    orphan_check_trait_ref(trait_ref, InCrate::Local)
 }
 
 /// Checks whether a trait-ref is potentially implementable by a crate.
@@ -559,13 +557,11 @@ pub fn orphan_check(tcx: TyCtxt<'_>, impl_def_id: DefId) -> Result<(), OrphanChe
 ///
 /// Note that this function is never called for types that have both type
 /// parameters and inference variables.
+#[instrument(level = "trace", ret)]
 fn orphan_check_trait_ref<'tcx>(
-    tcx: TyCtxt<'tcx>,
     trait_ref: ty::TraitRef<'tcx>,
     in_crate: InCrate,
 ) -> Result<(), OrphanCheckErr<'tcx>> {
-    debug!("orphan_check_trait_ref(trait_ref={:?}, in_crate={:?})", trait_ref, in_crate);
-
     if trait_ref.needs_infer() && trait_ref.needs_subst() {
         bug!(
             "can't orphan check a trait ref with both params and inference variables {:?}",
@@ -573,7 +569,7 @@ fn orphan_check_trait_ref<'tcx>(
         );
     }
 
-    let mut checker = OrphanChecker::new(tcx, in_crate);
+    let mut checker = OrphanChecker::new(in_crate);
     match trait_ref.visit_with(&mut checker) {
         ControlFlow::Continue(()) => Err(OrphanCheckErr::NonLocalInputType(checker.non_local_tys)),
         ControlFlow::Break(OrphanCheckEarlyExit::ParamTy(ty)) => {
@@ -592,7 +588,6 @@ fn orphan_check_trait_ref<'tcx>(
 }
 
 struct OrphanChecker<'tcx> {
-    tcx: TyCtxt<'tcx>,
     in_crate: InCrate,
     in_self_ty: bool,
     /// Ignore orphan check failures and exclusively search for the first
@@ -602,9 +597,8 @@ struct OrphanChecker<'tcx> {
 }
 
 impl<'tcx> OrphanChecker<'tcx> {
-    fn new(tcx: TyCtxt<'tcx>, in_crate: InCrate) -> Self {
+    fn new(in_crate: InCrate) -> Self {
         OrphanChecker {
-            tcx,
             in_crate,
             in_self_ty: true,
             search_first_local_ty: false,
@@ -614,12 +608,12 @@ impl<'tcx> OrphanChecker<'tcx> {
 
     fn found_non_local_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<OrphanCheckEarlyExit<'tcx>> {
         self.non_local_tys.push((t, self.in_self_ty));
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 
     fn found_param_ty(&mut self, t: Ty<'tcx>) -> ControlFlow<OrphanCheckEarlyExit<'tcx>> {
         if self.search_first_local_ty {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         } else {
             ControlFlow::Break(OrphanCheckEarlyExit::ParamTy(t))
         }
@@ -641,7 +635,7 @@ enum OrphanCheckEarlyExit<'tcx> {
 impl<'tcx> TypeVisitor<'tcx> for OrphanChecker<'tcx> {
     type BreakTy = OrphanCheckEarlyExit<'tcx>;
     fn visit_region(&mut self, _r: ty::Region<'tcx>) -> ControlFlow<Self::BreakTy> {
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 
     fn visit_ty(&mut self, ty: Ty<'tcx>) -> ControlFlow<Self::BreakTy> {
@@ -697,13 +691,17 @@ impl<'tcx> TypeVisitor<'tcx> for OrphanChecker<'tcx> {
                 }
             }
             ty::Error(_) => ControlFlow::Break(OrphanCheckEarlyExit::LocalTy(ty)),
-            ty::Closure(..) | ty::Generator(..) | ty::GeneratorWitness(..) => {
-                self.tcx.sess.delay_span_bug(
-                    DUMMY_SP,
-                    format!("ty_is_local invoked on closure or generator: {:?}", ty),
-                );
-                ControlFlow::Break(OrphanCheckEarlyExit::LocalTy(ty))
+            ty::Closure(did, ..) | ty::Generator(did, ..) => {
+                if self.def_id_is_local(did) {
+                    ControlFlow::Break(OrphanCheckEarlyExit::LocalTy(ty))
+                } else {
+                    self.found_non_local_ty(ty)
+                }
             }
+            // This should only be created when checking whether we have to check whether some
+            // auto trait impl applies. There will never be multiple impls, so we can just
+            // act as if it were a local type here.
+            ty::GeneratorWitness(_) => ControlFlow::Break(OrphanCheckEarlyExit::LocalTy(ty)),
             ty::Alias(ty::Opaque, ..) => {
                 // This merits some explanation.
                 // Normally, opaque types are not involved when performing
@@ -756,6 +754,6 @@ impl<'tcx> TypeVisitor<'tcx> for OrphanChecker<'tcx> {
     /// parameters, allowing uncovered const parameters in impls seems more useful
     /// than allowing `impl<T> Trait<local_fn_ptr, T> for i32` to compile.
     fn visit_const(&mut self, _c: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
index 71fb6058cd2..f779d9dd8d9 100644
--- a/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
+++ b/compiler/rustc_trait_selection/src/traits/const_evaluatable.rs
@@ -198,7 +198,7 @@ fn satisfied_from_param_env<'tcx>(
                 // If we start allowing directly writing `ConstKind::Expr` without an intermediate anon const
                 // this will be incorrect. It might be worth investigating making `predicates_of` elaborate
                 // all of the `ConstEvaluatable` bounds rather than having a visitor here.
-                ControlFlow::CONTINUE
+                ControlFlow::Continue(())
             }
         }
     }
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
index df57c0f60fa..0419bb3f724 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/ambiguity.rs
@@ -82,9 +82,7 @@ pub fn recompute_applicable_impls<'tcx>(
 
     let predicates =
         tcx.predicates_of(obligation.cause.body_id.owner.to_def_id()).instantiate_identity(tcx);
-    for obligation in
-        elaborate_predicates_with_span(tcx, std::iter::zip(predicates.predicates, predicates.spans))
-    {
+    for obligation in elaborate_predicates_with_span(tcx, predicates.into_iter()) {
         let kind = obligation.predicate.kind();
         if let ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred)) = kind.skip_binder()
             && param_env_candidate_may_apply(kind.rebind(trait_pred))
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
index 32b0f65176c..52971486c55 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/mod.rs
@@ -1350,6 +1350,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                         expected_trait_ref,
                         obligation.cause.code(),
                         found_node,
+                        obligation.param_env,
                     )
                 } else {
                     let (closure_span, closure_arg_span, found) = found_did
@@ -2932,7 +2933,7 @@ impl<'tcx> ty::TypeVisitor<'tcx> for HasNumericInferVisitor {
         if matches!(ty.kind(), ty::Infer(ty::FloatVar(_) | ty::IntVar(_))) {
             ControlFlow::Break(())
         } else {
-            ControlFlow::CONTINUE
+            ControlFlow::Continue(())
         }
     }
 }
diff --git a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
index 8d707b74d92..39e50b2accf 100644
--- a/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
+++ b/compiler/rustc_trait_selection/src/traits/error_reporting/suggestions.rs
@@ -283,6 +283,7 @@ pub trait TypeErrCtxtExt<'tcx> {
         expected: ty::PolyTraitRef<'tcx>,
         cause: &ObligationCauseCode<'tcx>,
         found_node: Option<Node<'_>>,
+        param_env: ty::ParamEnv<'tcx>,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed>;
 
     fn note_conflicting_closure_bounds(
@@ -1123,7 +1124,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
                     Some((DefIdOrName::DefId(def_id), fn_sig.output(), fn_sig.inputs().map_bound(|inputs| &inputs[1..])))
                 }
                 ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
-                    self.tcx.bound_item_bounds(def_id).subst(self.tcx, substs).iter().find_map(|pred| {
+                    self.tcx.item_bounds(def_id).subst(self.tcx, substs).iter().find_map(|pred| {
                         if let ty::PredicateKind::Clause(ty::Clause::Projection(proj)) = pred.kind().skip_binder()
                         && Some(proj.projection_ty.def_id) == self.tcx.lang_items().fn_once_output()
                         // args tuple will always be substs[1]
@@ -1978,6 +1979,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         expected: ty::PolyTraitRef<'tcx>,
         cause: &ObligationCauseCode<'tcx>,
         found_node: Option<Node<'_>>,
+        param_env: ty::ParamEnv<'tcx>,
     ) -> DiagnosticBuilder<'tcx, ErrorGuaranteed> {
         pub(crate) fn build_fn_sig_ty<'tcx>(
             infcx: &InferCtxt<'tcx>,
@@ -2040,7 +2042,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
         self.note_conflicting_closure_bounds(cause, &mut err);
 
         if let Some(found_node) = found_node {
-            hint_missing_borrow(span, found, expected, found_node, &mut err);
+            hint_missing_borrow(self, param_env, span, found, expected, found_node, &mut err);
         }
 
         err
@@ -2070,7 +2072,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
             // Find another predicate whose self-type is equal to the expected self type,
             // but whose substs don't match.
-            let other_pred = std::iter::zip(&predicates.predicates, &predicates.spans)
+            let other_pred = predicates.into_iter()
                 .enumerate()
                 .find(|(other_idx, (pred, _))| match pred.kind().skip_binder() {
                     ty::PredicateKind::Clause(ty::Clause::Trait(trait_pred))
@@ -2095,7 +2097,7 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
             // If we found one, then it's very likely the cause of the error.
             if let Some((_, (_, other_pred_span))) = other_pred {
                 err.span_note(
-                    *other_pred_span,
+                    other_pred_span,
                     "closure inferred to have a different signature due to this bound",
                 );
             }
@@ -3747,6 +3749,8 @@ impl<'tcx> TypeErrCtxtExt<'tcx> for TypeErrCtxt<'_, 'tcx> {
 
 /// Add a hint to add a missing borrow or remove an unnecessary one.
 fn hint_missing_borrow<'tcx>(
+    infcx: &InferCtxt<'tcx>,
+    param_env: ty::ParamEnv<'tcx>,
     span: Span,
     found: Ty<'tcx>,
     expected: Ty<'tcx>,
@@ -3769,7 +3773,7 @@ fn hint_missing_borrow<'tcx>(
     // This could be a variant constructor, for example.
     let Some(fn_decl) = found_node.fn_decl() else { return; };
 
-    let arg_spans = fn_decl.inputs.iter().map(|ty| ty.span);
+    let args = fn_decl.inputs.iter().map(|ty| ty);
 
     fn get_deref_type_and_refs(mut ty: Ty<'_>) -> (Ty<'_>, usize) {
         let mut refs = 0;
@@ -3785,21 +3789,34 @@ fn hint_missing_borrow<'tcx>(
     let mut to_borrow = Vec::new();
     let mut remove_borrow = Vec::new();
 
-    for ((found_arg, expected_arg), arg_span) in found_args.zip(expected_args).zip(arg_spans) {
+    for ((found_arg, expected_arg), arg) in found_args.zip(expected_args).zip(args) {
         let (found_ty, found_refs) = get_deref_type_and_refs(*found_arg);
         let (expected_ty, expected_refs) = get_deref_type_and_refs(*expected_arg);
 
-        if found_ty == expected_ty {
+        if infcx.can_eq(param_env, found_ty, expected_ty).is_ok() {
             if found_refs < expected_refs {
-                to_borrow.push((arg_span, expected_arg.to_string()));
+                to_borrow.push((arg.span.shrink_to_lo(), "&".repeat(expected_refs - found_refs)));
             } else if found_refs > expected_refs {
-                remove_borrow.push((arg_span, expected_arg.to_string()));
+                let mut span = arg.span.shrink_to_lo();
+                let mut left = found_refs - expected_refs;
+                let mut ty = arg;
+                while let hir::TyKind::Ref(_, mut_ty) = &ty.kind && left > 0 {
+                    span = span.with_hi(mut_ty.ty.span.lo());
+                    ty = mut_ty.ty;
+                    left -= 1;
+                }
+                let sugg = if left == 0 {
+                    (span, String::new())
+                } else {
+                    (arg.span, expected_arg.to_string())
+                };
+                remove_borrow.push(sugg);
             }
         }
     }
 
     if !to_borrow.is_empty() {
-        err.multipart_suggestion(
+        err.multipart_suggestion_verbose(
             "consider borrowing the argument",
             to_borrow,
             Applicability::MaybeIncorrect,
@@ -3807,7 +3824,7 @@ fn hint_missing_borrow<'tcx>(
     }
 
     if !remove_borrow.is_empty() {
-        err.multipart_suggestion(
+        err.multipart_suggestion_verbose(
             "do not borrow the argument",
             remove_borrow,
             Applicability::MaybeIncorrect,
diff --git a/compiler/rustc_trait_selection/src/traits/misc.rs b/compiler/rustc_trait_selection/src/traits/misc.rs
index b6ded4ce5a3..a41a601f2db 100644
--- a/compiler/rustc_trait_selection/src/traits/misc.rs
+++ b/compiler/rustc_trait_selection/src/traits/misc.rs
@@ -1,29 +1,36 @@
 //! Miscellaneous type-system utilities that are too small to deserve their own modules.
 
-use crate::infer::InferCtxtExt as _;
 use crate::traits::{self, ObligationCause};
 
+use rustc_data_structures::fx::FxIndexSet;
 use rustc_hir as hir;
-use rustc_infer::infer::TyCtxtInferExt;
+use rustc_infer::infer::{RegionResolutionError, TyCtxtInferExt};
+use rustc_infer::{infer::outlives::env::OutlivesEnvironment, traits::FulfillmentError};
 use rustc_middle::ty::{self, Ty, TyCtxt, TypeVisitable};
 
-use crate::traits::error_reporting::TypeErrCtxtExt;
+use super::outlives_bounds::InferCtxtExt;
 
-#[derive(Clone)]
 pub enum CopyImplementationError<'tcx> {
-    InfrigingFields(Vec<(&'tcx ty::FieldDef, Ty<'tcx>)>),
+    InfrigingFields(Vec<(&'tcx ty::FieldDef, Ty<'tcx>, InfringingFieldsReason<'tcx>)>),
     NotAnAdt,
     HasDestructor,
 }
 
-pub fn can_type_implement_copy<'tcx>(
+pub enum InfringingFieldsReason<'tcx> {
+    Fulfill(Vec<FulfillmentError<'tcx>>),
+    Regions(Vec<RegionResolutionError<'tcx>>),
+}
+
+/// Checks that the fields of the type (an ADT) all implement copy.
+///
+/// If fields don't implement copy, return an error containing a list of
+/// those violating fields. If it's not an ADT, returns `Err(NotAnAdt)`.
+pub fn type_allowed_to_implement_copy<'tcx>(
     tcx: TyCtxt<'tcx>,
     param_env: ty::ParamEnv<'tcx>,
     self_type: Ty<'tcx>,
     parent_cause: ObligationCause<'tcx>,
 ) -> Result<(), CopyImplementationError<'tcx>> {
-    // FIXME: (@jroesch) float this code up
-    let infcx = tcx.infer_ctxt().build();
     let (adt, substs) = match self_type.kind() {
         // These types used to have a builtin impl.
         // Now libcore provides that impl.
@@ -42,42 +49,82 @@ pub fn can_type_implement_copy<'tcx>(
         _ => return Err(CopyImplementationError::NotAnAdt),
     };
 
+    let copy_def_id = tcx.require_lang_item(hir::LangItem::Copy, Some(parent_cause.span));
+
     let mut infringing = Vec::new();
     for variant in adt.variants() {
         for field in &variant.fields {
-            let ty = field.ty(tcx, substs);
-            if ty.references_error() {
+            // Do this per-field to get better error messages.
+            let infcx = tcx.infer_ctxt().build();
+            let ocx = traits::ObligationCtxt::new(&infcx);
+
+            let unnormalized_ty = field.ty(tcx, substs);
+            if unnormalized_ty.references_error() {
                 continue;
             }
-            let span = tcx.def_span(field.did);
+
+            let field_span = tcx.def_span(field.did);
+            let field_ty_span = match tcx.hir().get_if_local(field.did) {
+                Some(hir::Node::Field(field_def)) => field_def.ty.span,
+                _ => field_span,
+            };
+
             // FIXME(compiler-errors): This gives us better spans for bad
             // projection types like in issue-50480.
             // If the ADT has substs, point to the cause we are given.
             // If it does not, then this field probably doesn't normalize
             // to begin with, and point to the bad field's span instead.
-            let cause = if field
+            let normalization_cause = if field
                 .ty(tcx, traits::InternalSubsts::identity_for_item(tcx, adt.did()))
                 .has_non_region_param()
             {
                 parent_cause.clone()
             } else {
-                ObligationCause::dummy_with_span(span)
-            };
-            match traits::fully_normalize(&infcx, cause, param_env, ty) {
-                Ok(ty) => {
-                    if !infcx.type_is_copy_modulo_regions(param_env, ty, span) {
-                        infringing.push((field, ty));
-                    }
-                }
-                Err(errors) => {
-                    infcx.err_ctxt().report_fulfillment_errors(&errors, None);
-                }
+                ObligationCause::dummy_with_span(field_ty_span)
             };
+            let ty = ocx.normalize(&normalization_cause, param_env, unnormalized_ty);
+            let normalization_errors = ocx.select_where_possible();
+            if !normalization_errors.is_empty() {
+                tcx.sess.delay_span_bug(field_span, format!("couldn't normalize struct field `{unnormalized_ty}` when checking Copy implementation"));
+                continue;
+            }
+
+            ocx.register_bound(
+                ObligationCause::dummy_with_span(field_ty_span),
+                param_env,
+                ty,
+                copy_def_id,
+            );
+            let errors = ocx.select_all_or_error();
+            if !errors.is_empty() {
+                infringing.push((field, ty, InfringingFieldsReason::Fulfill(errors)));
+            }
+
+            // Check regions assuming the self type of the impl is WF
+            let outlives_env = OutlivesEnvironment::with_bounds(
+                param_env,
+                Some(&infcx),
+                infcx.implied_bounds_tys(
+                    param_env,
+                    parent_cause.body_id,
+                    FxIndexSet::from_iter([self_type]),
+                ),
+            );
+            infcx.process_registered_region_obligations(
+                outlives_env.region_bound_pairs(),
+                param_env,
+            );
+            let errors = infcx.resolve_regions(&outlives_env);
+            if !errors.is_empty() {
+                infringing.push((field, ty, InfringingFieldsReason::Regions(errors)));
+            }
         }
     }
+
     if !infringing.is_empty() {
         return Err(CopyImplementationError::InfrigingFields(infringing));
     }
+
     if adt.has_dtor(tcx) {
         return Err(CopyImplementationError::HasDestructor);
     }
diff --git a/compiler/rustc_trait_selection/src/traits/mod.rs b/compiler/rustc_trait_selection/src/traits/mod.rs
index 13aa067844a..f036a311d46 100644
--- a/compiler/rustc_trait_selection/src/traits/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/mod.rs
@@ -115,14 +115,12 @@ pub fn predicates_for_generics<'tcx>(
     param_env: ty::ParamEnv<'tcx>,
     generic_bounds: ty::InstantiatedPredicates<'tcx>,
 ) -> impl Iterator<Item = PredicateObligation<'tcx>> {
-    std::iter::zip(generic_bounds.predicates, generic_bounds.spans).enumerate().map(
-        move |(idx, (predicate, span))| Obligation {
-            cause: cause(idx, span),
-            recursion_depth: 0,
-            param_env,
-            predicate,
-        },
-    )
+    generic_bounds.into_iter().enumerate().map(move |(idx, (predicate, span))| Obligation {
+        cause: cause(idx, span),
+        recursion_depth: 0,
+        param_env,
+        predicate,
+    })
 }
 
 /// Determines whether the type `ty` is known to meet `bound` and
@@ -495,7 +493,7 @@ fn is_impossible_method(tcx: TyCtxt<'_>, (impl_def_id, trait_item_def_id): (DefI
                 && let param_def_id = self.generics.type_param(param, self.tcx).def_id
                 && self.tcx.parent(param_def_id) == self.trait_item_def_id
             {
-                return ControlFlow::BREAK;
+                return ControlFlow::Break(());
             }
             t.super_visit_with(self)
         }
@@ -504,7 +502,7 @@ fn is_impossible_method(tcx: TyCtxt<'_>, (impl_def_id, trait_item_def_id): (DefI
                 && let param_def_id = self.generics.region_param(&param, self.tcx).def_id
                 && self.tcx.parent(param_def_id) == self.trait_item_def_id
             {
-                return ControlFlow::BREAK;
+                return ControlFlow::Break(());
             }
             r.super_visit_with(self)
         }
@@ -513,7 +511,7 @@ fn is_impossible_method(tcx: TyCtxt<'_>, (impl_def_id, trait_item_def_id): (DefI
                 && let param_def_id = self.generics.const_param(&param, self.tcx).def_id
                 && self.tcx.parent(param_def_id) == self.trait_item_def_id
             {
-                return ControlFlow::BREAK;
+                return ControlFlow::Break(());
             }
             ct.super_visit_with(self)
         }
diff --git a/compiler/rustc_trait_selection/src/traits/object_safety.rs b/compiler/rustc_trait_selection/src/traits/object_safety.rs
index 9a0e3d298ed..c9121212cd8 100644
--- a/compiler/rustc_trait_selection/src/traits/object_safety.rs
+++ b/compiler/rustc_trait_selection/src/traits/object_safety.rs
@@ -783,16 +783,16 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
             match t.kind() {
                 ty::Param(_) => {
                     if t == self.tcx.types.self_param {
-                        ControlFlow::BREAK
+                        ControlFlow::Break(())
                     } else {
-                        ControlFlow::CONTINUE
+                        ControlFlow::Continue(())
                     }
                 }
                 ty::Alias(ty::Projection, ref data)
                     if self.tcx.def_kind(data.def_id) == DefKind::ImplTraitPlaceholder =>
                 {
                     // We'll deny these later in their own pass
-                    ControlFlow::CONTINUE
+                    ControlFlow::Continue(())
                 }
                 ty::Alias(ty::Projection, ref data) => {
                     // This is a projected type `<Foo as SomeTrait>::X`.
@@ -820,7 +820,7 @@ fn contains_illegal_self_type_reference<'tcx, T: TypeVisitable<'tcx>>(
                         .contains(&data.trait_ref(self.tcx).def_id);
 
                     if is_supertrait_of_current_trait {
-                        ControlFlow::CONTINUE // do not walk contained types, do not report error, do collect $200
+                        ControlFlow::Continue(()) // do not walk contained types, do not report error, do collect $200
                     } else {
                         t.super_visit_with(self) // DO walk contained types, POSSIBLY reporting an error
                     }
diff --git a/compiler/rustc_trait_selection/src/traits/project.rs b/compiler/rustc_trait_selection/src/traits/project.rs
index eecd4cf03be..fbc7eccedc8 100644
--- a/compiler/rustc_trait_selection/src/traits/project.rs
+++ b/compiler/rustc_trait_selection/src/traits/project.rs
@@ -1375,7 +1375,7 @@ fn assemble_candidates_from_trait_def<'cx, 'tcx>(
     // Check whether the self-type is itself a projection.
     // If so, extract what we know from the trait and try to come up with a good answer.
     let bounds = match *obligation.predicate.self_ty().kind() {
-        ty::Alias(_, ref data) => tcx.bound_item_bounds(data.def_id).subst(tcx, data.substs),
+        ty::Alias(_, ref data) => tcx.item_bounds(data.def_id).subst(tcx, data.substs),
         ty::Infer(ty::TyVar(_)) => {
             // If the self-type is an inference variable, then it MAY wind up
             // being a projected type, so induce an ambiguity.
@@ -2259,25 +2259,23 @@ fn confirm_impl_trait_in_trait_candidate<'tcx>(
         tcx.predicates_of(impl_fn_def_id).instantiate(tcx, impl_fn_substs),
         &mut obligations,
     );
-    obligations.extend(std::iter::zip(predicates.predicates, predicates.spans).map(
-        |(pred, span)| {
-            Obligation::with_depth(
-                tcx,
-                ObligationCause::new(
-                    obligation.cause.span,
-                    obligation.cause.body_id,
-                    if span.is_dummy() {
-                        super::ItemObligation(impl_fn_def_id)
-                    } else {
-                        super::BindingObligation(impl_fn_def_id, span)
-                    },
-                ),
-                obligation.recursion_depth + 1,
-                obligation.param_env,
-                pred,
-            )
-        },
-    ));
+    obligations.extend(predicates.into_iter().map(|(pred, span)| {
+        Obligation::with_depth(
+            tcx,
+            ObligationCause::new(
+                obligation.cause.span,
+                obligation.cause.body_id,
+                if span.is_dummy() {
+                    super::ItemObligation(impl_fn_def_id)
+                } else {
+                    super::BindingObligation(impl_fn_def_id, span)
+                },
+            ),
+            obligation.recursion_depth + 1,
+            obligation.param_env,
+            pred,
+        )
+    }));
 
     let ty = normalize_with_depth_to(
         selcx,
@@ -2303,10 +2301,10 @@ fn assoc_ty_own_obligations<'cx, 'tcx>(
     nested: &mut Vec<PredicateObligation<'tcx>>,
 ) {
     let tcx = selcx.tcx();
-    let own = tcx
+    let predicates = tcx
         .predicates_of(obligation.predicate.def_id)
         .instantiate_own(tcx, obligation.predicate.substs);
-    for (predicate, span) in std::iter::zip(own.predicates, own.spans) {
+    for (predicate, span) in predicates {
         let normalized = normalize_with_depth_to(
             selcx,
             obligation.param_env,
diff --git a/compiler/rustc_trait_selection/src/traits/query/normalize.rs b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
index c6ef13e185b..27247271d1f 100644
--- a/compiler/rustc_trait_selection/src/traits/query/normalize.rs
+++ b/compiler/rustc_trait_selection/src/traits/query/normalize.rs
@@ -133,7 +133,7 @@ impl<'tcx> TypeVisitor<'tcx> for MaxEscapingBoundVarVisitor {
                 .escaping
                 .max(t.outer_exclusive_binder().as_usize() - self.outer_index.as_usize());
         }
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 
     #[inline]
@@ -145,7 +145,7 @@ impl<'tcx> TypeVisitor<'tcx> for MaxEscapingBoundVarVisitor {
             }
             _ => {}
         }
-        ControlFlow::CONTINUE
+        ControlFlow::Continue(())
     }
 
     fn visit_const(&mut self, ct: ty::Const<'tcx>) -> ControlFlow<Self::BreakTy> {
@@ -153,7 +153,7 @@ impl<'tcx> TypeVisitor<'tcx> for MaxEscapingBoundVarVisitor {
             ty::ConstKind::Bound(debruijn, _) if debruijn >= self.outer_index => {
                 self.escaping =
                     self.escaping.max(debruijn.as_usize() - self.outer_index.as_usize());
-                ControlFlow::CONTINUE
+                ControlFlow::Continue(())
             }
             _ => ct.super_visit_with(self),
         }
@@ -201,7 +201,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
         // wait to fold the substs.
 
         // Wrap this in a closure so we don't accidentally return from the outer function
-        let res = (|| match *ty.kind() {
+        let res = match *ty.kind() {
             // This is really important. While we *can* handle this, this has
             // severe performance implications for large opaque types with
             // late-bound regions. See `issue-88862` benchmark.
@@ -210,7 +210,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
             {
                 // Only normalize `impl Trait` outside of type inference, usually in codegen.
                 match self.param_env.reveal() {
-                    Reveal::UserFacing => ty.try_super_fold_with(self),
+                    Reveal::UserFacing => ty.try_super_fold_with(self)?,
 
                     Reveal::All => {
                         let substs = substs.try_fold_with(self)?;
@@ -239,7 +239,7 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
                         }
                         let folded_ty = ensure_sufficient_stack(|| self.try_fold_ty(concrete_ty));
                         self.anon_depth -= 1;
-                        folded_ty
+                        folded_ty?
                     }
                 }
             }
@@ -287,9 +287,9 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
                 // `tcx.normalize_projection_ty` may normalize to a type that still has
                 // unevaluated consts, so keep normalizing here if that's the case.
                 if res != ty && res.has_type_flags(ty::TypeFlags::HAS_CT_PROJECTION) {
-                    Ok(res.try_super_fold_with(self)?)
+                    res.try_super_fold_with(self)?
                 } else {
-                    Ok(res)
+                    res
                 }
             }
 
@@ -344,14 +344,14 @@ impl<'cx, 'tcx> FallibleTypeFolder<'tcx> for QueryNormalizer<'cx, 'tcx> {
                 // `tcx.normalize_projection_ty` may normalize to a type that still has
                 // unevaluated consts, so keep normalizing here if that's the case.
                 if res != ty && res.has_type_flags(ty::TypeFlags::HAS_CT_PROJECTION) {
-                    Ok(res.try_super_fold_with(self)?)
+                    res.try_super_fold_with(self)?
                 } else {
-                    Ok(res)
+                    res
                 }
             }
 
-            _ => ty.try_super_fold_with(self),
-        })()?;
+            _ => ty.try_super_fold_with(self)?,
+        };
 
         self.cache.insert(ty, res);
         Ok(res)
diff --git a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
index f41d3c460ac..82a59831be3 100644
--- a/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/confirmation.rs
@@ -160,8 +160,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             _ => bug!("projection candidate for unexpected type: {:?}", placeholder_self_ty),
         };
 
-        let candidate_predicate =
-            tcx.bound_item_bounds(def_id).map_bound(|i| i[idx]).subst(tcx, substs);
+        let candidate_predicate = tcx.item_bounds(def_id).map_bound(|i| i[idx]).subst(tcx, substs);
         let candidate = candidate_predicate
             .to_opt_poly_trait_pred()
             .expect("projection candidate is not a trait predicate")
@@ -185,9 +184,8 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         })?);
 
         if let ty::Alias(ty::Projection, ..) = placeholder_self_ty.kind() {
-            let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs).predicates;
-            debug!(?predicates, "projection predicates");
-            for predicate in predicates {
+            let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs);
+            for (predicate, _) in predicates {
                 let normalized = normalize_with_depth_to(
                     self,
                     obligation.param_env,
@@ -511,7 +509,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
             // This maybe belongs in wf, but that can't (doesn't) handle
             // higher-ranked things.
             // Prevent, e.g., `dyn Iterator<Item = str>`.
-            for bound in self.tcx().bound_item_bounds(assoc_type).transpose_iter() {
+            for bound in self.tcx().item_bounds(assoc_type).transpose_iter() {
                 let subst_bound =
                     if defs.count() == 0 {
                         bound.subst(tcx, trait_predicate.trait_ref.substs)
diff --git a/compiler/rustc_trait_selection/src/traits/select/mod.rs b/compiler/rustc_trait_selection/src/traits/select/mod.rs
index 6c8df0a794f..f90da95d516 100644
--- a/compiler/rustc_trait_selection/src/traits/select/mod.rs
+++ b/compiler/rustc_trait_selection/src/traits/select/mod.rs
@@ -1604,7 +1604,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 );
             }
         };
-        let bounds = tcx.bound_item_bounds(def_id).subst(tcx, substs);
+        let bounds = tcx.item_bounds(def_id).subst(tcx, substs);
 
         // The bounds returned by `item_bounds` may contain duplicates after
         // normalization, so try to deduplicate when possible to avoid
@@ -2558,12 +2558,11 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
         // obligation will normalize to `<$0 as Iterator>::Item = $1` and
         // `$1: Copy`, so we must ensure the obligations are emitted in
         // that order.
-        let predicates = tcx.bound_predicates_of(def_id);
-        debug!(?predicates);
-        assert_eq!(predicates.0.parent, None);
-        let mut obligations = Vec::with_capacity(predicates.0.predicates.len());
-        for (predicate, span) in predicates.0.predicates {
-            let span = *span;
+        let predicates = tcx.predicates_of(def_id);
+        assert_eq!(predicates.parent, None);
+        let predicates = predicates.instantiate_own(tcx, substs);
+        let mut obligations = Vec::with_capacity(predicates.len());
+        for (predicate, span) in predicates {
             let cause = cause.clone().derived_cause(parent_trait_pred, |derived| {
                 ImplDerivedObligation(Box::new(ImplDerivedObligationCause {
                     derived,
@@ -2576,7 +2575,7 @@ impl<'cx, 'tcx> SelectionContext<'cx, 'tcx> {
                 param_env,
                 cause.clone(),
                 recursion_depth,
-                predicates.rebind(*predicate).subst(tcx, substs),
+                predicate,
                 &mut obligations,
             );
             obligations.push(Obligation { cause, recursion_depth, param_env, predicate });
diff --git a/compiler/rustc_trait_selection/src/traits/structural_match.rs b/compiler/rustc_trait_selection/src/traits/structural_match.rs
index 892a7afd799..f398fb06c18 100644
--- a/compiler/rustc_trait_selection/src/traits/structural_match.rs
+++ b/compiler/rustc_trait_selection/src/traits/structural_match.rs
@@ -107,25 +107,25 @@ impl<'tcx> TypeVisitor<'tcx> for Search<'tcx> {
             ty::FnDef(..) => {
                 // Types of formals and return in `fn(_) -> _` are also irrelevant;
                 // so we do not recur into them via `super_visit_with`
-                return ControlFlow::CONTINUE;
+                return ControlFlow::Continue(());
             }
             ty::Array(_, n)
                 if { n.try_eval_usize(self.tcx, ty::ParamEnv::reveal_all()) == Some(0) } =>
             {
                 // rust-lang/rust#62336: ignore type of contents
                 // for empty array.
-                return ControlFlow::CONTINUE;
+                return ControlFlow::Continue(());
             }
             ty::Bool | ty::Char | ty::Int(_) | ty::Uint(_) | ty::Str | ty::Never => {
                 // These primitive types are always structural match.
                 //
                 // `Never` is kind of special here, but as it is not inhabitable, this should be fine.
-                return ControlFlow::CONTINUE;
+                return ControlFlow::Continue(());
             }
 
             ty::FnPtr(..) => {
                 if !self.adt_const_param {
-                    return ControlFlow::CONTINUE;
+                    return ControlFlow::Continue(());
                 } else {
                     return ControlFlow::Break(ty);
                 }
@@ -147,7 +147,7 @@ impl<'tcx> TypeVisitor<'tcx> for Search<'tcx> {
                     // Even though `NonStructural` does not implement `PartialEq`,
                     // structural equality on `T` does not recur into the raw
                     // pointer. Therefore, one can still use `C` in a pattern.
-                    return ControlFlow::CONTINUE;
+                    return ControlFlow::Continue(());
                 } else {
                     return ControlFlow::Break(ty);
                 }
@@ -155,7 +155,7 @@ impl<'tcx> TypeVisitor<'tcx> for Search<'tcx> {
 
             ty::Float(_) => {
                 if !self.adt_const_param {
-                    return ControlFlow::CONTINUE;
+                    return ControlFlow::Continue(());
                 } else {
                     return ControlFlow::Break(ty);
                 }
@@ -172,13 +172,13 @@ impl<'tcx> TypeVisitor<'tcx> for Search<'tcx> {
                 self.tcx.sess.delay_span_bug(self.span, "ty::Error in structural-match check");
                 // We still want to check other types after encountering an error,
                 // as this may still emit relevant errors.
-                return ControlFlow::CONTINUE;
+                return ControlFlow::Continue(());
             }
         };
 
         if !self.seen.insert(adt_def.did()) {
             debug!("Search already seen adt_def: {:?}", adt_def);
-            return ControlFlow::CONTINUE;
+            return ControlFlow::Continue(());
         }
 
         if !self.type_marked_structural(ty) {
diff --git a/compiler/rustc_trait_selection/src/traits/vtable.rs b/compiler/rustc_trait_selection/src/traits/vtable.rs
index 5ec9c2a24cd..64daca714c3 100644
--- a/compiler/rustc_trait_selection/src/traits/vtable.rs
+++ b/compiler/rustc_trait_selection/src/traits/vtable.rs
@@ -261,7 +261,10 @@ fn vtable_entries<'tcx>(
                     // Note that this method could then never be called, so we
                     // do not want to try and codegen it, in that case (see #23435).
                     let predicates = tcx.predicates_of(def_id).instantiate_own(tcx, substs);
-                    if impossible_predicates(tcx, predicates.predicates) {
+                    if impossible_predicates(
+                        tcx,
+                        predicates.map(|(predicate, _)| predicate).collect(),
+                    ) {
                         debug!("vtable_entries: predicates do not hold");
                         return VtblEntry::Vacant;
                     }
diff --git a/compiler/rustc_trait_selection/src/traits/wf.rs b/compiler/rustc_trait_selection/src/traits/wf.rs
index e6f3dd17d21..12d4cb4fc69 100644
--- a/compiler/rustc_trait_selection/src/traits/wf.rs
+++ b/compiler/rustc_trait_selection/src/traits/wf.rs
@@ -654,7 +654,7 @@ impl<'tcx> WfPredicates<'tcx> {
                     // All of the requirements on type parameters
                     // have already been checked for `impl Trait` in
                     // return position. We do need to check type-alias-impl-trait though.
-                    if ty::is_impl_trait_defn(self.tcx, def_id).is_none() {
+                    if self.tcx.is_type_alias_impl_trait(def_id) {
                         let obligations = self.nominal_obligations(def_id, substs);
                         self.out.extend(obligations);
                     }
@@ -736,7 +736,7 @@ impl<'tcx> WfPredicates<'tcx> {
         trace!("{:#?}", predicates);
         debug_assert_eq!(predicates.predicates.len(), origins.len());
 
-        iter::zip(iter::zip(predicates.predicates, predicates.spans), origins.into_iter().rev())
+        iter::zip(predicates, origins.into_iter().rev())
             .map(|((mut pred, span), origin_def_id)| {
                 let code = if span.is_dummy() {
                     traits::ItemObligation(origin_def_id)
diff --git a/compiler/rustc_traits/src/chalk/db.rs b/compiler/rustc_traits/src/chalk/db.rs
index 7c0cae1e7bd..f146de3966b 100644
--- a/compiler/rustc_traits/src/chalk/db.rs
+++ b/compiler/rustc_traits/src/chalk/db.rs
@@ -7,7 +7,7 @@
 //! `crate::chalk::lowering` (to lower rustc types into Chalk types).
 
 use rustc_middle::traits::ChalkRustInterner as RustInterner;
-use rustc_middle::ty::{self, AssocKind, EarlyBinder, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable};
+use rustc_middle::ty::{self, AssocKind, Ty, TyCtxt, TypeFoldable, TypeSuperFoldable};
 use rustc_middle::ty::{InternalSubsts, SubstsRef};
 use rustc_target::abi::{Integer, IntegerType};
 
@@ -38,13 +38,12 @@ impl<'tcx> RustIrDatabase<'tcx> {
         def_id: DefId,
         bound_vars: SubstsRef<'tcx>,
     ) -> Vec<chalk_ir::QuantifiedWhereClause<RustInterner<'tcx>>> {
-        let predicates = self.interner.tcx.predicates_defined_on(def_id).predicates;
-        predicates
-            .iter()
-            .map(|(wc, _)| EarlyBinder(*wc).subst(self.interner.tcx, bound_vars))
-            .filter_map(|wc| LowerInto::<
-                    Option<chalk_ir::QuantifiedWhereClause<RustInterner<'tcx>>>
-                    >::lower_into(wc, self.interner)).collect()
+        self.interner
+            .tcx
+            .predicates_defined_on(def_id)
+            .instantiate_own(self.interner.tcx, bound_vars)
+            .filter_map(|(wc, _)| LowerInto::lower_into(wc, self.interner))
+            .collect()
     }
 
     fn bounds_for<T>(&self, def_id: DefId, bound_vars: SubstsRef<'tcx>) -> Vec<T>
diff --git a/compiler/rustc_traits/src/implied_outlives_bounds.rs b/compiler/rustc_traits/src/implied_outlives_bounds.rs
index 010233d7718..7d2d8433c93 100644
--- a/compiler/rustc_traits/src/implied_outlives_bounds.rs
+++ b/compiler/rustc_traits/src/implied_outlives_bounds.rs
@@ -154,11 +154,8 @@ fn implied_bounds_from_components<'tcx>(
             match component {
                 Component::Region(r) => Some(OutlivesBound::RegionSubRegion(sub_region, r)),
                 Component::Param(p) => Some(OutlivesBound::RegionSubParam(sub_region, p)),
-                Component::Projection(p) => Some(OutlivesBound::RegionSubProjection(sub_region, p)),
-                Component::Opaque(def_id, substs) => {
-                    Some(OutlivesBound::RegionSubOpaque(sub_region, def_id, substs))
-                }
-                Component::EscapingProjection(_) =>
+                Component::Alias(p) => Some(OutlivesBound::RegionSubAlias(sub_region, p)),
+                Component::EscapingAlias(_) =>
                 // If the projection has escaping regions, don't
                 // try to infer any implied bounds even for its
                 // free components. This is conservative, because
diff --git a/compiler/rustc_traits/src/type_op.rs b/compiler/rustc_traits/src/type_op.rs
index aa5c83ac2e6..f35c5e44882 100644
--- a/compiler/rustc_traits/src/type_op.rs
+++ b/compiler/rustc_traits/src/type_op.rs
@@ -17,7 +17,6 @@ use rustc_trait_selection::traits::query::type_op::subtype::Subtype;
 use rustc_trait_selection::traits::query::{Fallible, NoSolution};
 use rustc_trait_selection::traits::{Normalized, Obligation, ObligationCause, ObligationCtxt};
 use std::fmt;
-use std::iter::zip;
 
 pub(crate) fn provide(p: &mut Providers) {
     *p = Providers {
@@ -108,9 +107,7 @@ fn relate_mir_and_user_substs<'tcx>(
     let instantiated_predicates = tcx.predicates_of(def_id).instantiate(tcx, substs);
 
     debug!(?instantiated_predicates);
-    for (instantiated_predicate, predicate_span) in
-        zip(instantiated_predicates.predicates, instantiated_predicates.spans)
-    {
+    for (instantiated_predicate, predicate_span) in instantiated_predicates {
         let span = if span == DUMMY_SP { predicate_span } else { span };
         let cause = ObligationCause::new(
             span,
diff --git a/compiler/rustc_transmute/src/lib.rs b/compiler/rustc_transmute/src/lib.rs
index 384d03106b1..b3b9a67b26e 100644
--- a/compiler/rustc_transmute/src/lib.rs
+++ b/compiler/rustc_transmute/src/lib.rs
@@ -1,4 +1,4 @@
-#![feature(alloc_layout_extra, control_flow_enum, decl_macro, iterator_try_reduce, never_type)]
+#![feature(alloc_layout_extra, decl_macro, iterator_try_reduce, never_type)]
 #![allow(dead_code, unused_variables)]
 #![deny(rustc::untranslatable_diagnostic)]
 #![deny(rustc::diagnostic_outside_of_impl)]
diff --git a/compiler/rustc_ty_utils/src/abi.rs b/compiler/rustc_ty_utils/src/abi.rs
index dc1dd1bfaf8..91a505a72fa 100644
--- a/compiler/rustc_ty_utils/src/abi.rs
+++ b/compiler/rustc_ty_utils/src/abi.rs
@@ -108,21 +108,41 @@ fn fn_sig_for_fn_abi<'tcx>(
             // `Generator::resume(...) -> GeneratorState` function in case we
             // have an ordinary generator, or the `Future::poll(...) -> Poll`
             // function in case this is a special generator backing an async construct.
-            let ret_ty = if tcx.generator_is_async(did) {
-                let state_did = tcx.require_lang_item(LangItem::Poll, None);
-                let state_adt_ref = tcx.adt_def(state_did);
-                let state_substs = tcx.intern_substs(&[sig.return_ty.into()]);
-                tcx.mk_adt(state_adt_ref, state_substs)
+            let (resume_ty, ret_ty) = if tcx.generator_is_async(did) {
+                // The signature should be `Future::poll(_, &mut Context<'_>) -> Poll<Output>`
+                let poll_did = tcx.require_lang_item(LangItem::Poll, None);
+                let poll_adt_ref = tcx.adt_def(poll_did);
+                let poll_substs = tcx.intern_substs(&[sig.return_ty.into()]);
+                let ret_ty = tcx.mk_adt(poll_adt_ref, poll_substs);
+
+                // We have to replace the `ResumeTy` that is used for type and borrow checking
+                // with `&mut Context<'_>` which is used in codegen.
+                #[cfg(debug_assertions)]
+                {
+                    if let ty::Adt(resume_ty_adt, _) = sig.resume_ty.kind() {
+                        let expected_adt =
+                            tcx.adt_def(tcx.require_lang_item(LangItem::ResumeTy, None));
+                        assert_eq!(*resume_ty_adt, expected_adt);
+                    } else {
+                        panic!("expected `ResumeTy`, found `{:?}`", sig.resume_ty);
+                    };
+                }
+                let context_mut_ref = tcx.mk_task_context();
+
+                (context_mut_ref, ret_ty)
             } else {
+                // The signature should be `Generator::resume(_, Resume) -> GeneratorState<Yield, Return>`
                 let state_did = tcx.require_lang_item(LangItem::GeneratorState, None);
                 let state_adt_ref = tcx.adt_def(state_did);
                 let state_substs = tcx.intern_substs(&[sig.yield_ty.into(), sig.return_ty.into()]);
-                tcx.mk_adt(state_adt_ref, state_substs)
+                let ret_ty = tcx.mk_adt(state_adt_ref, state_substs);
+
+                (sig.resume_ty, ret_ty)
             };
 
             ty::Binder::bind_with_vars(
                 tcx.mk_fn_sig(
-                    [env_ty, sig.resume_ty].iter(),
+                    [env_ty, resume_ty].iter(),
                     &ret_ty,
                     false,
                     hir::Unsafety::Normal,
@@ -219,8 +239,7 @@ fn adjust_for_rust_scalar<'tcx>(
         return;
     }
 
-    // Scalars which have invalid values cannot be undef.
-    if !scalar.is_always_valid(&cx) {
+    if !scalar.is_uninit_valid() {
         attrs.set(ArgAttribute::NoUndef);
     }
 
@@ -246,11 +265,6 @@ fn adjust_for_rust_scalar<'tcx>(
                 PointerKind::SharedMutable | PointerKind::UniqueOwned => Size::ZERO,
             };
 
-            // `Box`, `&T`, and `&mut T` cannot be undef.
-            // Note that this only applies to the value of the pointer itself;
-            // this attribute doesn't make it UB for the pointed-to data to be undef.
-            attrs.set(ArgAttribute::NoUndef);
-
             // The aliasing rules for `Box<T>` are still not decided, but currently we emit
             // `noalias` for it. This can be turned off using an unstable flag.
             // See https://github.com/rust-lang/unsafe-code-guidelines/issues/326
diff --git a/compiler/rustc_ty_utils/src/consts.rs b/compiler/rustc_ty_utils/src/consts.rs
index a9b4e1420ea..a9fbad55dac 100644
--- a/compiler/rustc_ty_utils/src/consts.rs
+++ b/compiler/rustc_ty_utils/src/consts.rs
@@ -302,13 +302,53 @@ impl<'a, 'tcx> IsThirPolymorphic<'a, 'tcx> {
         }
 
         match expr.kind {
-            thir::ExprKind::NamedConst { substs, .. } => substs.has_non_region_param(),
+            thir::ExprKind::NamedConst { substs, .. }
+            | thir::ExprKind::ConstBlock { substs, .. } => substs.has_non_region_param(),
             thir::ExprKind::ConstParam { .. } => true,
             thir::ExprKind::Repeat { value, count } => {
                 self.visit_expr(&self.thir()[value]);
                 count.has_non_region_param()
             }
-            _ => false,
+            thir::ExprKind::Scope { .. }
+            | thir::ExprKind::Box { .. }
+            | thir::ExprKind::If { .. }
+            | thir::ExprKind::Call { .. }
+            | thir::ExprKind::Deref { .. }
+            | thir::ExprKind::Binary { .. }
+            | thir::ExprKind::LogicalOp { .. }
+            | thir::ExprKind::Unary { .. }
+            | thir::ExprKind::Cast { .. }
+            | thir::ExprKind::Use { .. }
+            | thir::ExprKind::NeverToAny { .. }
+            | thir::ExprKind::Pointer { .. }
+            | thir::ExprKind::Loop { .. }
+            | thir::ExprKind::Let { .. }
+            | thir::ExprKind::Match { .. }
+            | thir::ExprKind::Block { .. }
+            | thir::ExprKind::Assign { .. }
+            | thir::ExprKind::AssignOp { .. }
+            | thir::ExprKind::Field { .. }
+            | thir::ExprKind::Index { .. }
+            | thir::ExprKind::VarRef { .. }
+            | thir::ExprKind::UpvarRef { .. }
+            | thir::ExprKind::Borrow { .. }
+            | thir::ExprKind::AddressOf { .. }
+            | thir::ExprKind::Break { .. }
+            | thir::ExprKind::Continue { .. }
+            | thir::ExprKind::Return { .. }
+            | thir::ExprKind::Array { .. }
+            | thir::ExprKind::Tuple { .. }
+            | thir::ExprKind::Adt(_)
+            | thir::ExprKind::PlaceTypeAscription { .. }
+            | thir::ExprKind::ValueTypeAscription { .. }
+            | thir::ExprKind::Closure(_)
+            | thir::ExprKind::Literal { .. }
+            | thir::ExprKind::NonHirLiteral { .. }
+            | thir::ExprKind::ZstLiteral { .. }
+            | thir::ExprKind::StaticRef { .. }
+            | thir::ExprKind::InlineAsm(_)
+            | thir::ExprKind::ThreadLocalRef(_)
+            | thir::ExprKind::Yield { .. } => false,
         }
     }
     fn pat_is_poly(&mut self, pat: &thir::Pat<'tcx>) -> bool {
diff --git a/compiler/rustc_ty_utils/src/lib.rs b/compiler/rustc_ty_utils/src/lib.rs
index 7ad5cbc01cc..0853de601b0 100644
--- a/compiler/rustc_ty_utils/src/lib.rs
+++ b/compiler/rustc_ty_utils/src/lib.rs
@@ -6,7 +6,6 @@
 
 #![doc(html_root_url = "https://doc.rust-lang.org/nightly/nightly-rustc/")]
 #![feature(let_chains)]
-#![feature(control_flow_enum)]
 #![feature(never_type)]
 #![feature(box_patterns)]
 #![recursion_limit = "256"]
diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index afc3a3dc6a8..ca75c3895f4 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -106,6 +106,7 @@
 #![feature(const_size_of_val)]
 #![feature(const_align_of_val)]
 #![feature(const_ptr_read)]
+#![feature(const_maybe_uninit_zeroed)]
 #![feature(const_maybe_uninit_write)]
 #![feature(const_maybe_uninit_as_mut_ptr)]
 #![feature(const_refs_to_cell)]
diff --git a/library/alloc/src/slice.rs b/library/alloc/src/slice.rs
index e9886fc5717..fecacc2bb63 100644
--- a/library/alloc/src/slice.rs
+++ b/library/alloc/src/slice.rs
@@ -19,10 +19,12 @@ use core::cmp::Ordering::{self, Less};
 use core::mem::{self, SizedTypeProperties};
 #[cfg(not(no_global_oom_handling))]
 use core::ptr;
+#[cfg(not(no_global_oom_handling))]
+use core::slice::sort;
 
 use crate::alloc::Allocator;
 #[cfg(not(no_global_oom_handling))]
-use crate::alloc::Global;
+use crate::alloc::{self, Global};
 #[cfg(not(no_global_oom_handling))]
 use crate::borrow::ToOwned;
 use crate::boxed::Box;
@@ -206,7 +208,7 @@ impl<T> [T] {
     where
         T: Ord,
     {
-        merge_sort(self, T::lt);
+        stable_sort(self, T::lt);
     }
 
     /// Sorts the slice with a comparator function.
@@ -262,7 +264,7 @@ impl<T> [T] {
     where
         F: FnMut(&T, &T) -> Ordering,
     {
-        merge_sort(self, |a, b| compare(a, b) == Less);
+        stable_sort(self, |a, b| compare(a, b) == Less);
     }
 
     /// Sorts the slice with a key extraction function.
@@ -305,7 +307,7 @@ impl<T> [T] {
         F: FnMut(&T) -> K,
         K: Ord,
     {
-        merge_sort(self, |a, b| f(a).lt(&f(b)));
+        stable_sort(self, |a, b| f(a).lt(&f(b)));
     }
 
     /// Sorts the slice with a key extraction function.
@@ -812,324 +814,52 @@ impl<T: Clone> ToOwned for [T] {
 // Sorting
 ////////////////////////////////////////////////////////////////////////////////
 
-/// Inserts `v[0]` into pre-sorted sequence `v[1..]` so that whole `v[..]` becomes sorted.
-///
-/// This is the integral subroutine of insertion sort.
-#[cfg(not(no_global_oom_handling))]
-fn insert_head<T, F>(v: &mut [T], is_less: &mut F)
-where
-    F: FnMut(&T, &T) -> bool,
-{
-    if v.len() >= 2 && is_less(&v[1], &v[0]) {
-        unsafe {
-            // There are three ways to implement insertion here:
-            //
-            // 1. Swap adjacent elements until the first one gets to its final destination.
-            //    However, this way we copy data around more than is necessary. If elements are big
-            //    structures (costly to copy), this method will be slow.
-            //
-            // 2. Iterate until the right place for the first element is found. Then shift the
-            //    elements succeeding it to make room for it and finally place it into the
-            //    remaining hole. This is a good method.
-            //
-            // 3. Copy the first element into a temporary variable. Iterate until the right place
-            //    for it is found. As we go along, copy every traversed element into the slot
-            //    preceding it. Finally, copy data from the temporary variable into the remaining
-            //    hole. This method is very good. Benchmarks demonstrated slightly better
-            //    performance than with the 2nd method.
-            //
-            // All methods were benchmarked, and the 3rd showed best results. So we chose that one.
-            let tmp = mem::ManuallyDrop::new(ptr::read(&v[0]));
-
-            // Intermediate state of the insertion process is always tracked by `hole`, which
-            // serves two purposes:
-            // 1. Protects integrity of `v` from panics in `is_less`.
-            // 2. Fills the remaining hole in `v` in the end.
-            //
-            // Panic safety:
-            //
-            // If `is_less` panics at any point during the process, `hole` will get dropped and
-            // fill the hole in `v` with `tmp`, thus ensuring that `v` still holds every object it
-            // initially held exactly once.
-            let mut hole = InsertionHole { src: &*tmp, dest: &mut v[1] };
-            ptr::copy_nonoverlapping(&v[1], &mut v[0], 1);
-
-            for i in 2..v.len() {
-                if !is_less(&v[i], &*tmp) {
-                    break;
-                }
-                ptr::copy_nonoverlapping(&v[i], &mut v[i - 1], 1);
-                hole.dest = &mut v[i];
-            }
-            // `hole` gets dropped and thus copies `tmp` into the remaining hole in `v`.
-        }
-    }
-
-    // When dropped, copies from `src` into `dest`.
-    struct InsertionHole<T> {
-        src: *const T,
-        dest: *mut T,
-    }
-
-    impl<T> Drop for InsertionHole<T> {
-        fn drop(&mut self) {
-            unsafe {
-                ptr::copy_nonoverlapping(self.src, self.dest, 1);
-            }
-        }
-    }
-}
-
-/// Merges non-decreasing runs `v[..mid]` and `v[mid..]` using `buf` as temporary storage, and
-/// stores the result into `v[..]`.
-///
-/// # Safety
-///
-/// The two slices must be non-empty and `mid` must be in bounds. Buffer `buf` must be long enough
-/// to hold a copy of the shorter slice. Also, `T` must not be a zero-sized type.
-#[cfg(not(no_global_oom_handling))]
-unsafe fn merge<T, F>(v: &mut [T], mid: usize, buf: *mut T, is_less: &mut F)
-where
-    F: FnMut(&T, &T) -> bool,
-{
-    let len = v.len();
-    let v = v.as_mut_ptr();
-    let (v_mid, v_end) = unsafe { (v.add(mid), v.add(len)) };
-
-    // The merge process first copies the shorter run into `buf`. Then it traces the newly copied
-    // run and the longer run forwards (or backwards), comparing their next unconsumed elements and
-    // copying the lesser (or greater) one into `v`.
-    //
-    // As soon as the shorter run is fully consumed, the process is done. If the longer run gets
-    // consumed first, then we must copy whatever is left of the shorter run into the remaining
-    // hole in `v`.
-    //
-    // Intermediate state of the process is always tracked by `hole`, which serves two purposes:
-    // 1. Protects integrity of `v` from panics in `is_less`.
-    // 2. Fills the remaining hole in `v` if the longer run gets consumed first.
-    //
-    // Panic safety:
-    //
-    // If `is_less` panics at any point during the process, `hole` will get dropped and fill the
-    // hole in `v` with the unconsumed range in `buf`, thus ensuring that `v` still holds every
-    // object it initially held exactly once.
-    let mut hole;
-
-    if mid <= len - mid {
-        // The left run is shorter.
-        unsafe {
-            ptr::copy_nonoverlapping(v, buf, mid);
-            hole = MergeHole { start: buf, end: buf.add(mid), dest: v };
-        }
-
-        // Initially, these pointers point to the beginnings of their arrays.
-        let left = &mut hole.start;
-        let mut right = v_mid;
-        let out = &mut hole.dest;
-
-        while *left < hole.end && right < v_end {
-            // Consume the lesser side.
-            // If equal, prefer the left run to maintain stability.
-            unsafe {
-                let to_copy = if is_less(&*right, &**left) {
-                    get_and_increment(&mut right)
-                } else {
-                    get_and_increment(left)
-                };
-                ptr::copy_nonoverlapping(to_copy, get_and_increment(out), 1);
-            }
-        }
-    } else {
-        // The right run is shorter.
-        unsafe {
-            ptr::copy_nonoverlapping(v_mid, buf, len - mid);
-            hole = MergeHole { start: buf, end: buf.add(len - mid), dest: v_mid };
-        }
-
-        // Initially, these pointers point past the ends of their arrays.
-        let left = &mut hole.dest;
-        let right = &mut hole.end;
-        let mut out = v_end;
-
-        while v < *left && buf < *right {
-            // Consume the greater side.
-            // If equal, prefer the right run to maintain stability.
-            unsafe {
-                let to_copy = if is_less(&*right.sub(1), &*left.sub(1)) {
-                    decrement_and_get(left)
-                } else {
-                    decrement_and_get(right)
-                };
-                ptr::copy_nonoverlapping(to_copy, decrement_and_get(&mut out), 1);
-            }
-        }
-    }
-    // Finally, `hole` gets dropped. If the shorter run was not fully consumed, whatever remains of
-    // it will now be copied into the hole in `v`.
-
-    unsafe fn get_and_increment<T>(ptr: &mut *mut T) -> *mut T {
-        let old = *ptr;
-        *ptr = unsafe { ptr.add(1) };
-        old
-    }
-
-    unsafe fn decrement_and_get<T>(ptr: &mut *mut T) -> *mut T {
-        *ptr = unsafe { ptr.sub(1) };
-        *ptr
-    }
-
-    // When dropped, copies the range `start..end` into `dest..`.
-    struct MergeHole<T> {
-        start: *mut T,
-        end: *mut T,
-        dest: *mut T,
-    }
-
-    impl<T> Drop for MergeHole<T> {
-        fn drop(&mut self) {
-            // `T` is not a zero-sized type, and these are pointers into a slice's elements.
-            unsafe {
-                let len = self.end.sub_ptr(self.start);
-                ptr::copy_nonoverlapping(self.start, self.dest, len);
-            }
-        }
-    }
-}
-
-/// This merge sort borrows some (but not all) ideas from TimSort, which is described in detail
-/// [here](https://github.com/python/cpython/blob/main/Objects/listsort.txt).
-///
-/// The algorithm identifies strictly descending and non-descending subsequences, which are called
-/// natural runs. There is a stack of pending runs yet to be merged. Each newly found run is pushed
-/// onto the stack, and then some pairs of adjacent runs are merged until these two invariants are
-/// satisfied:
-///
-/// 1. for every `i` in `1..runs.len()`: `runs[i - 1].len > runs[i].len`
-/// 2. for every `i` in `2..runs.len()`: `runs[i - 2].len > runs[i - 1].len + runs[i].len`
-///
-/// The invariants ensure that the total running time is *O*(*n* \* log(*n*)) worst-case.
+#[inline]
 #[cfg(not(no_global_oom_handling))]
-fn merge_sort<T, F>(v: &mut [T], mut is_less: F)
+fn stable_sort<T, F>(v: &mut [T], mut is_less: F)
 where
     F: FnMut(&T, &T) -> bool,
 {
-    // Slices of up to this length get sorted using insertion sort.
-    const MAX_INSERTION: usize = 20;
-    // Very short runs are extended using insertion sort to span at least this many elements.
-    const MIN_RUN: usize = 10;
-
-    // Sorting has no meaningful behavior on zero-sized types.
     if T::IS_ZST {
+        // Sorting has no meaningful behavior on zero-sized types. Do nothing.
         return;
     }
 
-    let len = v.len();
-
-    // Short arrays get sorted in-place via insertion sort to avoid allocations.
-    if len <= MAX_INSERTION {
-        if len >= 2 {
-            for i in (0..len - 1).rev() {
-                insert_head(&mut v[i..], &mut is_less);
-            }
-        }
-        return;
-    }
-
-    // Allocate a buffer to use as scratch memory. We keep the length 0 so we can keep in it
-    // shallow copies of the contents of `v` without risking the dtors running on copies if
-    // `is_less` panics. When merging two sorted runs, this buffer holds a copy of the shorter run,
-    // which will always have length at most `len / 2`.
-    let mut buf = Vec::with_capacity(len / 2);
+    let elem_alloc_fn = |len: usize| -> *mut T {
+        // SAFETY: Creating the layout is safe as long as merge_sort never calls this with len >
+        // v.len(). Alloc in general will only be used as 'shadow-region' to store temporary swap
+        // elements.
+        unsafe { alloc::alloc(alloc::Layout::array::<T>(len).unwrap_unchecked()) as *mut T }
+    };
 
-    // In order to identify natural runs in `v`, we traverse it backwards. That might seem like a
-    // strange decision, but consider the fact that merges more often go in the opposite direction
-    // (forwards). According to benchmarks, merging forwards is slightly faster than merging
-    // backwards. To conclude, identifying runs by traversing backwards improves performance.
-    let mut runs = vec![];
-    let mut end = len;
-    while end > 0 {
-        // Find the next natural run, and reverse it if it's strictly descending.
-        let mut start = end - 1;
-        if start > 0 {
-            start -= 1;
-            unsafe {
-                if is_less(v.get_unchecked(start + 1), v.get_unchecked(start)) {
-                    while start > 0 && is_less(v.get_unchecked(start), v.get_unchecked(start - 1)) {
-                        start -= 1;
-                    }
-                    v[start..end].reverse();
-                } else {
-                    while start > 0 && !is_less(v.get_unchecked(start), v.get_unchecked(start - 1))
-                    {
-                        start -= 1;
-                    }
-                }
-            }
-        }
-
-        // Insert some more elements into the run if it's too short. Insertion sort is faster than
-        // merge sort on short sequences, so this significantly improves performance.
-        while start > 0 && end - start < MIN_RUN {
-            start -= 1;
-            insert_head(&mut v[start..end], &mut is_less);
+    let elem_dealloc_fn = |buf_ptr: *mut T, len: usize| {
+        // SAFETY: Creating the layout is safe as long as merge_sort never calls this with len >
+        // v.len(). The caller must ensure that buf_ptr was created by elem_alloc_fn with the same
+        // len.
+        unsafe {
+            alloc::dealloc(buf_ptr as *mut u8, alloc::Layout::array::<T>(len).unwrap_unchecked());
         }
+    };
 
-        // Push this run onto the stack.
-        runs.push(Run { start, len: end - start });
-        end = start;
-
-        // Merge some pairs of adjacent runs to satisfy the invariants.
-        while let Some(r) = collapse(&runs) {
-            let left = runs[r + 1];
-            let right = runs[r];
-            unsafe {
-                merge(
-                    &mut v[left.start..right.start + right.len],
-                    left.len,
-                    buf.as_mut_ptr(),
-                    &mut is_less,
-                );
-            }
-            runs[r] = Run { start: left.start, len: left.len + right.len };
-            runs.remove(r + 1);
+    let run_alloc_fn = |len: usize| -> *mut sort::TimSortRun {
+        // SAFETY: Creating the layout is safe as long as merge_sort never calls this with an
+        // obscene length or 0.
+        unsafe {
+            alloc::alloc(alloc::Layout::array::<sort::TimSortRun>(len).unwrap_unchecked())
+                as *mut sort::TimSortRun
         }
-    }
-
-    // Finally, exactly one run must remain in the stack.
-    debug_assert!(runs.len() == 1 && runs[0].start == 0 && runs[0].len == len);
+    };
 
-    // Examines the stack of runs and identifies the next pair of runs to merge. More specifically,
-    // if `Some(r)` is returned, that means `runs[r]` and `runs[r + 1]` must be merged next. If the
-    // algorithm should continue building a new run instead, `None` is returned.
-    //
-    // TimSort is infamous for its buggy implementations, as described here:
-    // http://envisage-project.eu/timsort-specification-and-verification/
-    //
-    // The gist of the story is: we must enforce the invariants on the top four runs on the stack.
-    // Enforcing them on just top three is not sufficient to ensure that the invariants will still
-    // hold for *all* runs in the stack.
-    //
-    // This function correctly checks invariants for the top four runs. Additionally, if the top
-    // run starts at index 0, it will always demand a merge operation until the stack is fully
-    // collapsed, in order to complete the sort.
-    #[inline]
-    fn collapse(runs: &[Run]) -> Option<usize> {
-        let n = runs.len();
-        if n >= 2
-            && (runs[n - 1].start == 0
-                || runs[n - 2].len <= runs[n - 1].len
-                || (n >= 3 && runs[n - 3].len <= runs[n - 2].len + runs[n - 1].len)
-                || (n >= 4 && runs[n - 4].len <= runs[n - 3].len + runs[n - 2].len))
-        {
-            if n >= 3 && runs[n - 3].len < runs[n - 1].len { Some(n - 3) } else { Some(n - 2) }
-        } else {
-            None
+    let run_dealloc_fn = |buf_ptr: *mut sort::TimSortRun, len: usize| {
+        // SAFETY: The caller must ensure that buf_ptr was created by elem_alloc_fn with the same
+        // len.
+        unsafe {
+            alloc::dealloc(
+                buf_ptr as *mut u8,
+                alloc::Layout::array::<sort::TimSortRun>(len).unwrap_unchecked(),
+            );
         }
-    }
+    };
 
-    #[derive(Clone, Copy)]
-    struct Run {
-        start: usize,
-        len: usize,
-    }
+    sort::merge_sort(v, &mut is_less, elem_alloc_fn, elem_dealloc_fn, run_alloc_fn, run_dealloc_fn);
 }
diff --git a/library/alloc/src/str.rs b/library/alloc/src/str.rs
index b28d20cda17..afbe5cfaf8e 100644
--- a/library/alloc/src/str.rs
+++ b/library/alloc/src/str.rs
@@ -559,10 +559,9 @@ impl str {
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
     #[inline]
     pub fn to_ascii_uppercase(&self) -> String {
-        let mut bytes = self.as_bytes().to_vec();
-        bytes.make_ascii_uppercase();
-        // make_ascii_uppercase() preserves the UTF-8 invariant.
-        unsafe { String::from_utf8_unchecked(bytes) }
+        let mut s = self.to_owned();
+        s.make_ascii_uppercase();
+        s
     }
 
     /// Returns a copy of this string where each character is mapped to its
@@ -592,10 +591,9 @@ impl str {
     #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
     #[inline]
     pub fn to_ascii_lowercase(&self) -> String {
-        let mut bytes = self.as_bytes().to_vec();
-        bytes.make_ascii_lowercase();
-        // make_ascii_lowercase() preserves the UTF-8 invariant.
-        unsafe { String::from_utf8_unchecked(bytes) }
+        let mut s = self.to_owned();
+        s.make_ascii_lowercase();
+        s
     }
 }
 
diff --git a/library/alloc/src/vec/drain.rs b/library/alloc/src/vec/drain.rs
index 541f99bcfab..2b1a787cc54 100644
--- a/library/alloc/src/vec/drain.rs
+++ b/library/alloc/src/vec/drain.rs
@@ -223,9 +223,9 @@ impl<T, A: Allocator> Drop for Drain<'_, T, A> {
         }
 
         // as_slice() must only be called when iter.len() is > 0 because
-        // vec::Splice modifies vec::Drain fields and may grow the vec which would invalidate
-        // the iterator's internal pointers. Creating a reference to deallocated memory
-        // is invalid even when it is zero-length
+        // it also gets touched by vec::Splice which may turn it into a dangling pointer
+        // which would make it and the vec pointer point to different allocations which would
+        // lead to invalid pointer arithmetic below.
         let drop_ptr = iter.as_slice().as_ptr();
 
         unsafe {
diff --git a/library/alloc/src/vec/is_zero.rs b/library/alloc/src/vec/is_zero.rs
index 26120270c0c..cb9adf05c25 100644
--- a/library/alloc/src/vec/is_zero.rs
+++ b/library/alloc/src/vec/is_zero.rs
@@ -4,7 +4,8 @@ use crate::boxed::Box;
 
 #[rustc_specialization_trait]
 pub(super) unsafe trait IsZero {
-    /// Whether this value's representation is all zeros
+    /// Whether this value's representation is all zeros,
+    /// or can be represented with all zeroes.
     fn is_zero(&self) -> bool;
 }
 
@@ -147,6 +148,23 @@ impl_is_zero_option_of_nonzero!(
     NonZeroIsize,
 );
 
+macro_rules! impl_is_zero_option_of_num {
+    ($($t:ty,)+) => {$(
+        unsafe impl IsZero for Option<$t> {
+            #[inline]
+            fn is_zero(&self) -> bool {
+                const {
+                    let none: Self = unsafe { core::mem::MaybeUninit::zeroed().assume_init() };
+                    assert!(none.is_none());
+                }
+                self.is_none()
+            }
+        }
+    )+};
+}
+
+impl_is_zero_option_of_num!(u8, u16, u32, u64, u128, i8, i16, i32, i64, i128, usize, isize,);
+
 unsafe impl<T: IsZero> IsZero for Wrapping<T> {
     #[inline]
     fn is_zero(&self) -> bool {
diff --git a/library/alloc/src/vec/splice.rs b/library/alloc/src/vec/splice.rs
index bad765c7f51..1861147fe72 100644
--- a/library/alloc/src/vec/splice.rs
+++ b/library/alloc/src/vec/splice.rs
@@ -54,6 +54,12 @@ impl<I: Iterator, A: Allocator> ExactSizeIterator for Splice<'_, I, A> {}
 impl<I: Iterator, A: Allocator> Drop for Splice<'_, I, A> {
     fn drop(&mut self) {
         self.drain.by_ref().for_each(drop);
+        // At this point draining is done and the only remaining tasks are splicing
+        // and moving things into the final place.
+        // Which means we can replace the slice::Iter with pointers that won't point to deallocated
+        // memory, so that Drain::drop is still allowed to call iter.len(), otherwise it would break
+        // the ptr.sub_ptr contract.
+        self.drain.iter = (&[]).iter();
 
         unsafe {
             if self.drain.tail_len == 0 {
diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index d6d2b055b23..2a93a242d51 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -1,7 +1,6 @@
 #![feature(allocator_api)]
 #![feature(alloc_layout_extra)]
 #![feature(assert_matches)]
-#![feature(box_syntax)]
 #![feature(btree_drain_filter)]
 #![feature(cow_is_borrowed)]
 #![feature(const_box)]
diff --git a/library/core/src/any.rs b/library/core/src/any.rs
index 9ca4947ed8f..c0fb0d993c3 100644
--- a/library/core/src/any.rs
+++ b/library/core/src/any.rs
@@ -662,7 +662,8 @@ impl dyn Any + Send + Sync {
 /// While `TypeId` implements `Hash`, `PartialOrd`, and `Ord`, it is worth
 /// noting that the hashes and ordering will vary between Rust releases. Beware
 /// of relying on them inside of your code!
-#[derive(Clone, Copy, PartialEq, Eq, PartialOrd, Ord, Debug, Hash)]
+#[derive(Clone, Copy, Debug, Hash, Eq)]
+#[derive_const(PartialEq, PartialOrd, Ord)]
 #[stable(feature = "rust1", since = "1.0.0")]
 pub struct TypeId {
     t: u64,
diff --git a/library/core/src/fmt/mod.rs b/library/core/src/fmt/mod.rs
index fa5073e3304..2a7ec544f9e 100644
--- a/library/core/src/fmt/mod.rs
+++ b/library/core/src/fmt/mod.rs
@@ -1355,11 +1355,11 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{}", Foo::new(2)), "2");
-    /// assert_eq!(&format!("{}", Foo::new(-1)), "-1");
-    /// assert_eq!(&format!("{}", Foo::new(0)), "0");
-    /// assert_eq!(&format!("{:#}", Foo::new(-1)), "-Foo 1");
-    /// assert_eq!(&format!("{:0>#8}", Foo::new(-1)), "00-Foo 1");
+    /// assert_eq!(format!("{}", Foo::new(2)), "2");
+    /// assert_eq!(format!("{}", Foo::new(-1)), "-1");
+    /// assert_eq!(format!("{}", Foo::new(0)), "0");
+    /// assert_eq!(format!("{:#}", Foo::new(-1)), "-Foo 1");
+    /// assert_eq!(format!("{:0>#8}", Foo::new(-1)), "00-Foo 1");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn pad_integral(&mut self, is_nonnegative: bool, prefix: &str, buf: &str) -> Result {
@@ -1452,8 +1452,8 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{Foo:<4}"), "Foo ");
-    /// assert_eq!(&format!("{Foo:0>4}"), "0Foo");
+    /// assert_eq!(format!("{Foo:<4}"), "Foo ");
+    /// assert_eq!(format!("{Foo:0>4}"), "0Foo");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn pad(&mut self, s: &str) -> Result {
@@ -1636,8 +1636,8 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{Foo}"), "Foo");
-    /// assert_eq!(&format!("{Foo:0>8}"), "Foo");
+    /// assert_eq!(format!("{Foo}"), "Foo");
+    /// assert_eq!(format!("{Foo:0>8}"), "Foo");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn write_str(&mut self, data: &str) -> Result {
@@ -1659,8 +1659,8 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{}", Foo(-1)), "Foo -1");
-    /// assert_eq!(&format!("{:0>8}", Foo(2)), "Foo 2");
+    /// assert_eq!(format!("{}", Foo(-1)), "Foo -1");
+    /// assert_eq!(format!("{:0>8}", Foo(2)), "Foo 2");
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     pub fn write_fmt(&mut self, fmt: Arguments<'_>) -> Result {
@@ -1703,8 +1703,8 @@ impl<'a> Formatter<'a> {
     /// }
     ///
     /// // We set alignment to the right with ">".
-    /// assert_eq!(&format!("{Foo:G>3}"), "GGG");
-    /// assert_eq!(&format!("{Foo:t>6}"), "tttttt");
+    /// assert_eq!(format!("{Foo:G>3}"), "GGG");
+    /// assert_eq!(format!("{Foo:t>6}"), "tttttt");
     /// ```
     #[must_use]
     #[stable(feature = "fmt_flags", since = "1.5.0")]
@@ -1738,10 +1738,10 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{Foo:<}"), "left");
-    /// assert_eq!(&format!("{Foo:>}"), "right");
-    /// assert_eq!(&format!("{Foo:^}"), "center");
-    /// assert_eq!(&format!("{Foo}"), "into the void");
+    /// assert_eq!(format!("{Foo:<}"), "left");
+    /// assert_eq!(format!("{Foo:>}"), "right");
+    /// assert_eq!(format!("{Foo:^}"), "center");
+    /// assert_eq!(format!("{Foo}"), "into the void");
     /// ```
     #[must_use]
     #[stable(feature = "fmt_flags_align", since = "1.28.0")]
@@ -1767,7 +1767,7 @@ impl<'a> Formatter<'a> {
     ///     fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
     ///         if let Some(width) = formatter.width() {
     ///             // If we received a width, we use it
-    ///             write!(formatter, "{:width$}", &format!("Foo({})", self.0), width = width)
+    ///             write!(formatter, "{:width$}", format!("Foo({})", self.0), width = width)
     ///         } else {
     ///             // Otherwise we do nothing special
     ///             write!(formatter, "Foo({})", self.0)
@@ -1775,8 +1775,8 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{:10}", Foo(23)), "Foo(23)   ");
-    /// assert_eq!(&format!("{}", Foo(23)), "Foo(23)");
+    /// assert_eq!(format!("{:10}", Foo(23)), "Foo(23)   ");
+    /// assert_eq!(format!("{}", Foo(23)), "Foo(23)");
     /// ```
     #[must_use]
     #[stable(feature = "fmt_flags", since = "1.5.0")]
@@ -1806,8 +1806,8 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{:.4}", Foo(23.2)), "Foo(23.2000)");
-    /// assert_eq!(&format!("{}", Foo(23.2)), "Foo(23.20)");
+    /// assert_eq!(format!("{:.4}", Foo(23.2)), "Foo(23.2000)");
+    /// assert_eq!(format!("{}", Foo(23.2)), "Foo(23.20)");
     /// ```
     #[must_use]
     #[stable(feature = "fmt_flags", since = "1.5.0")]
@@ -1837,9 +1837,9 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{:+}", Foo(23)), "Foo(+23)");
-    /// assert_eq!(&format!("{:+}", Foo(-23)), "Foo(-23)");
-    /// assert_eq!(&format!("{}", Foo(23)), "Foo(23)");
+    /// assert_eq!(format!("{:+}", Foo(23)), "Foo(+23)");
+    /// assert_eq!(format!("{:+}", Foo(-23)), "Foo(-23)");
+    /// assert_eq!(format!("{}", Foo(23)), "Foo(23)");
     /// ```
     #[must_use]
     #[stable(feature = "fmt_flags", since = "1.5.0")]
@@ -1867,8 +1867,8 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{:-}", Foo(23)), "-Foo(23)");
-    /// assert_eq!(&format!("{}", Foo(23)), "Foo(23)");
+    /// assert_eq!(format!("{:-}", Foo(23)), "-Foo(23)");
+    /// assert_eq!(format!("{}", Foo(23)), "Foo(23)");
     /// ```
     #[must_use]
     #[stable(feature = "fmt_flags", since = "1.5.0")]
@@ -1895,8 +1895,8 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{:#}", Foo(23)), "Foo(23)");
-    /// assert_eq!(&format!("{}", Foo(23)), "23");
+    /// assert_eq!(format!("{:#}", Foo(23)), "Foo(23)");
+    /// assert_eq!(format!("{}", Foo(23)), "23");
     /// ```
     #[must_use]
     #[stable(feature = "fmt_flags", since = "1.5.0")]
@@ -1922,7 +1922,7 @@ impl<'a> Formatter<'a> {
     ///     }
     /// }
     ///
-    /// assert_eq!(&format!("{:04}", Foo(23)), "23");
+    /// assert_eq!(format!("{:04}", Foo(23)), "23");
     /// ```
     #[must_use]
     #[stable(feature = "fmt_flags", since = "1.5.0")]
diff --git a/library/core/src/future/mod.rs b/library/core/src/future/mod.rs
index 5bfe001de46..c4fb3620946 100644
--- a/library/core/src/future/mod.rs
+++ b/library/core/src/future/mod.rs
@@ -112,6 +112,10 @@ pub unsafe fn get_context<'a, 'b>(cx: ResumeTy) -> &'a mut Context<'b> {
     unsafe { &mut *cx.0.as_ptr().cast() }
 }
 
+// FIXME(swatinem): This fn is currently needed to work around shortcomings
+// in type and lifetime inference.
+// See the comment at the bottom of `LoweringContext::make_async_expr` and
+// <https://github.com/rust-lang/rust/issues/104826>.
 #[doc(hidden)]
 #[unstable(feature = "gen_future", issue = "50547")]
 #[inline]
diff --git a/library/core/src/hint.rs b/library/core/src/hint.rs
index e8d724ab1ef..5a76e866923 100644
--- a/library/core/src/hint.rs
+++ b/library/core/src/hint.rs
@@ -219,6 +219,75 @@ pub fn spin_loop() {
 /// backend used. Programs cannot rely on `black_box` for *correctness* in any way.
 ///
 /// [`std::convert::identity`]: crate::convert::identity
+///
+/// # When is this useful?
+///
+/// First and foremost: `black_box` does _not_ guarantee any exact behavior and, in some cases, may
+/// do nothing at all. As such, it **must not be relied upon to control critical program behavior.**
+/// This _immediately_ precludes any direct use of this function for cryptographic or security
+/// purposes.
+///
+/// While not suitable in those mission-critical cases, `back_box`'s functionality can generally be
+/// relied upon for benchmarking, and should be used there. It will try to ensure that the
+/// compiler doesn't optimize away part of the intended test code based on context. For
+/// example:
+///
+/// ```
+/// fn contains(haystack: &[&str], needle: &str) -> bool {
+///     haystack.iter().any(|x| x == &needle)
+/// }
+///
+/// pub fn benchmark() {
+///     let haystack = vec!["abc", "def", "ghi", "jkl", "mno"];
+///     let needle = "ghi";
+///     for _ in 0..10 {
+///         contains(&haystack, needle);
+///     }
+/// }
+/// ```
+///
+/// The compiler could theoretically make optimizations like the following:
+///
+/// - `needle` and `haystack` are always the same, move the call to `contains` outside the loop and
+///   delete the loop
+/// - Inline `contains`
+/// - `needle` and `haystack` have values known at compile time, `contains` is always true. Remove
+///   the call and replace with `true`
+/// - Nothing is done with the result of `contains`: delete this function call entirely
+/// - `benchmark` now has no purpose: delete this function
+///
+/// It is not likely that all of the above happens, but the compiler is definitely able to make some
+/// optimizations that could result in a very inaccurate benchmark. This is where `black_box` comes
+/// in:
+///
+/// ```
+/// use std::hint::black_box;
+///
+/// // Same `contains` function
+/// fn contains(haystack: &[&str], needle: &str) -> bool {
+///     haystack.iter().any(|x| x == &needle)
+/// }
+///
+/// pub fn benchmark() {
+///     let haystack = vec!["abc", "def", "ghi", "jkl", "mno"];
+///     let needle = "ghi";
+///     for _ in 0..10 {
+///         // Adjust our benchmark loop contents
+///         black_box(contains(black_box(&haystack), black_box(needle)));
+///     }
+/// }
+/// ```
+///
+/// This essentially tells the compiler to block optimizations across any calls to `black_box`. So,
+/// it now:
+///
+/// - Treats both arguments to `contains` as unpredictable: the body of `contains` can no longer be
+///   optimized based on argument values
+/// - Treats the call to `contains` and its result as volatile: the body of `benchmark` cannot
+///   optimize this away
+///
+/// This makes our benchmark much more realistic to how the function would be used in situ, where
+/// arguments are usually not known at compile time and the result is used in some way.
 #[inline]
 #[stable(feature = "bench_black_box", since = "1.66.0")]
 #[rustc_const_unstable(feature = "const_black_box", issue = "none")]
diff --git a/library/core/src/intrinsics/mir.rs b/library/core/src/intrinsics/mir.rs
index 399d54f18c5..e3157b66902 100644
--- a/library/core/src/intrinsics/mir.rs
+++ b/library/core/src/intrinsics/mir.rs
@@ -259,6 +259,8 @@ define!("mir_unreachable", fn Unreachable() -> BasicBlock);
 define!("mir_drop", fn Drop<T>(place: T, goto: BasicBlock));
 define!("mir_drop_and_replace", fn DropAndReplace<T>(place: T, value: T, goto: BasicBlock));
 define!("mir_call", fn Call<T>(place: T, goto: BasicBlock, call: T));
+define!("mir_storage_live", fn StorageLive<T>(local: T));
+define!("mir_storage_dead", fn StorageDead<T>(local: T));
 define!("mir_retag", fn Retag<T>(place: T));
 define!("mir_move", fn Move<T>(place: T) -> T);
 define!("mir_static", fn Static<T>(s: T) -> &'static T);
diff --git a/library/core/src/ptr/const_ptr.rs b/library/core/src/ptr/const_ptr.rs
index 0a74c03d70f..7b1cb5488bc 100644
--- a/library/core/src/ptr/const_ptr.rs
+++ b/library/core/src/ptr/const_ptr.rs
@@ -202,14 +202,11 @@ impl<T: ?Sized> *const T {
     #[must_use]
     #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn addr(self) -> usize
-    where
-        T: Sized,
-    {
+    pub fn addr(self) -> usize {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
         // SAFETY: Pointer-to-integer transmutes are valid (if you are okay with losing the
         // provenance).
-        unsafe { mem::transmute(self) }
+        unsafe { mem::transmute(self.cast::<()>()) }
     }
 
     /// Gets the "address" portion of the pointer, and 'exposes' the "provenance" part for future
@@ -239,12 +236,9 @@ impl<T: ?Sized> *const T {
     #[must_use]
     #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn expose_addr(self) -> usize
-    where
-        T: Sized,
-    {
+    pub fn expose_addr(self) -> usize {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
-        self as usize
+        self.cast::<()>() as usize
     }
 
     /// Creates a new pointer with the given address.
@@ -262,10 +256,7 @@ impl<T: ?Sized> *const T {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn with_addr(self, addr: usize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn with_addr(self, addr: usize) -> Self {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
         //
         // In the mean-time, this operation is defined to be "as if" it was
@@ -288,10 +279,7 @@ impl<T: ?Sized> *const T {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self {
         self.with_addr(f(self.addr()))
     }
 
diff --git a/library/core/src/ptr/mut_ptr.rs b/library/core/src/ptr/mut_ptr.rs
index d70fb70c79f..ed1e3bd4812 100644
--- a/library/core/src/ptr/mut_ptr.rs
+++ b/library/core/src/ptr/mut_ptr.rs
@@ -208,14 +208,11 @@ impl<T: ?Sized> *mut T {
     #[must_use]
     #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn addr(self) -> usize
-    where
-        T: Sized,
-    {
+    pub fn addr(self) -> usize {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
         // SAFETY: Pointer-to-integer transmutes are valid (if you are okay with losing the
         // provenance).
-        unsafe { mem::transmute(self) }
+        unsafe { mem::transmute(self.cast::<()>()) }
     }
 
     /// Gets the "address" portion of the pointer, and 'exposes' the "provenance" part for future
@@ -245,12 +242,9 @@ impl<T: ?Sized> *mut T {
     #[must_use]
     #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn expose_addr(self) -> usize
-    where
-        T: Sized,
-    {
+    pub fn expose_addr(self) -> usize {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
-        self as usize
+        self.cast::<()>() as usize
     }
 
     /// Creates a new pointer with the given address.
@@ -268,10 +262,7 @@ impl<T: ?Sized> *mut T {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn with_addr(self, addr: usize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn with_addr(self, addr: usize) -> Self {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
         //
         // In the mean-time, this operation is defined to be "as if" it was
@@ -294,10 +285,7 @@ impl<T: ?Sized> *mut T {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self {
         self.with_addr(f(self.addr()))
     }
 
diff --git a/library/core/src/ptr/non_null.rs b/library/core/src/ptr/non_null.rs
index af79d4bbd83..8c1a6488605 100644
--- a/library/core/src/ptr/non_null.rs
+++ b/library/core/src/ptr/non_null.rs
@@ -268,10 +268,7 @@ impl<T: ?Sized> NonNull<T> {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn addr(self) -> NonZeroUsize
-    where
-        T: Sized,
-    {
+    pub fn addr(self) -> NonZeroUsize {
         // SAFETY: The pointer is guaranteed by the type to be non-null,
         // meaning that the address will be non-zero.
         unsafe { NonZeroUsize::new_unchecked(self.pointer.addr()) }
@@ -286,10 +283,7 @@ impl<T: ?Sized> NonNull<T> {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn with_addr(self, addr: NonZeroUsize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn with_addr(self, addr: NonZeroUsize) -> Self {
         // SAFETY: The result of `ptr::from::with_addr` is non-null because `addr` is guaranteed to be non-zero.
         unsafe { NonNull::new_unchecked(self.pointer.with_addr(addr.get()) as *mut _) }
     }
@@ -303,10 +297,7 @@ impl<T: ?Sized> NonNull<T> {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn map_addr(self, f: impl FnOnce(NonZeroUsize) -> NonZeroUsize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn map_addr(self, f: impl FnOnce(NonZeroUsize) -> NonZeroUsize) -> Self {
         self.with_addr(f(self.addr()))
     }
 
diff --git a/library/core/src/slice/iter.rs b/library/core/src/slice/iter.rs
index c3e7f2eb302..90ab43d1289 100644
--- a/library/core/src/slice/iter.rs
+++ b/library/core/src/slice/iter.rs
@@ -6,7 +6,7 @@ mod macros;
 use crate::cmp;
 use crate::cmp::Ordering;
 use crate::fmt;
-use crate::intrinsics::{assume, exact_div, unchecked_sub};
+use crate::intrinsics::assume;
 use crate::iter::{FusedIterator, TrustedLen, TrustedRandomAccess, TrustedRandomAccessNoCoerce};
 use crate::marker::{PhantomData, Send, Sized, Sync};
 use crate::mem::{self, SizedTypeProperties};
@@ -35,12 +35,6 @@ impl<'a, T> IntoIterator for &'a mut [T] {
     }
 }
 
-// Macro helper functions
-#[inline(always)]
-fn size_from_ptr<T>(_: *const T) -> usize {
-    mem::size_of::<T>()
-}
-
 /// Immutable slice iterator
 ///
 /// This struct is created by the [`iter`] method on [slices].
diff --git a/library/core/src/slice/iter/macros.rs b/library/core/src/slice/iter/macros.rs
index 55af4cb61dc..0fd57b197aa 100644
--- a/library/core/src/slice/iter/macros.rs
+++ b/library/core/src/slice/iter/macros.rs
@@ -9,30 +9,20 @@ macro_rules! is_empty {
     };
 }
 
-// To get rid of some bounds checks (see `position`), we compute the length in a somewhat
-// unexpected way. (Tested by `codegen/slice-position-bounds-check`.)
 macro_rules! len {
     ($self: ident) => {{
         #![allow(unused_unsafe)] // we're sometimes used within an unsafe block
 
         let start = $self.ptr;
-        let size = size_from_ptr(start.as_ptr());
-        if size == 0 {
-            // This _cannot_ use `unchecked_sub` because we depend on wrapping
+        if T::IS_ZST {
+            // This _cannot_ use `ptr_sub` because we depend on wrapping
             // to represent the length of long ZST slice iterators.
             $self.end.addr().wrapping_sub(start.as_ptr().addr())
         } else {
-            // We know that `start <= end`, so can do better than `offset_from`,
-            // which needs to deal in signed. By setting appropriate flags here
-            // we can tell LLVM this, which helps it remove bounds checks.
-            // SAFETY: By the type invariant, `start <= end`
-            let diff = unsafe { unchecked_sub($self.end.addr(), start.as_ptr().addr()) };
-            // By also telling LLVM that the pointers are apart by an exact
-            // multiple of the type size, it can optimize `len() == 0` down to
-            // `start == end` instead of `(end - start) < size`.
-            // SAFETY: By the type invariant, the pointers are aligned so the
-            //         distance between them must be a multiple of pointee size
-            unsafe { exact_div(diff, size) }
+            // To get rid of some bounds checks (see `position`), we use ptr_sub instead of
+            // offset_from (Tested by `codegen/slice-position-bounds-check`.)
+            // SAFETY: by the type invariant pointers are aligned and `start <= end`
+            unsafe { $self.end.sub_ptr(start.as_ptr()) }
         }
     }};
 }
diff --git a/library/core/src/slice/mod.rs b/library/core/src/slice/mod.rs
index df7fe2bf76d..d93a3a57ecd 100644
--- a/library/core/src/slice/mod.rs
+++ b/library/core/src/slice/mod.rs
@@ -29,13 +29,19 @@ use crate::slice;
 /// Pure rust memchr implementation, taken from rust-memchr
 pub mod memchr;
 
+#[unstable(
+    feature = "slice_internals",
+    issue = "none",
+    reason = "exposed from core to be reused in std;"
+)]
+pub mod sort;
+
 mod ascii;
 mod cmp;
 mod index;
 mod iter;
 mod raw;
 mod rotate;
-mod sort;
 mod specialize;
 
 #[stable(feature = "rust1", since = "1.0.0")]
@@ -781,6 +787,22 @@ impl<T> [T] {
     /// let mut iter = slice.windows(4);
     /// assert!(iter.next().is_none());
     /// ```
+    ///
+    /// There's no `windows_mut`, as that existing would let safe code violate the
+    /// "only one `&mut` at a time to the same thing" rule.  However, you can sometimes
+    /// use [`Cell::as_slice_of_cells`](crate::cell::Cell::as_slice_of_cells) in
+    /// conjunction with `windows` to accomplish something similar:
+    /// ```
+    /// use std::cell::Cell;
+    ///
+    /// let mut array = ['R', 'u', 's', 't', ' ', '2', '0', '1', '5'];
+    /// let slice = &mut array[..];
+    /// let slice_of_cells: &[Cell<char>] = Cell::from_mut(slice).as_slice_of_cells();
+    /// for w in slice_of_cells.windows(3) {
+    ///     Cell::swap(&w[0], &w[2]);
+    /// }
+    /// assert_eq!(array, ['s', 't', ' ', '2', '0', '1', '5', 'u', 'R']);
+    /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[inline]
     pub fn windows(&self, size: usize) -> Windows<'_, T> {
diff --git a/library/core/src/slice/sort.rs b/library/core/src/slice/sort.rs
index 4d2fcd91784..2181f9a8118 100644
--- a/library/core/src/slice/sort.rs
+++ b/library/core/src/slice/sort.rs
@@ -5,6 +5,9 @@
 //!
 //! Unstable sorting is compatible with core because it doesn't allocate memory, unlike our
 //! stable sorting implementation.
+//!
+//! In addition it also contains the core logic of the stable sort used by `slice::sort` based on
+//! TimSort.
 
 use crate::cmp;
 use crate::mem::{self, MaybeUninit, SizedTypeProperties};
@@ -831,6 +834,15 @@ fn partition_at_index_loop<'a, T, F>(
 ) where
     F: FnMut(&T, &T) -> bool,
 {
+    // Limit the amount of iterations and fall back to heapsort, similarly to `slice::sort_unstable`.
+    // This lowers the worst case running time from O(n^2) to O(n log n).
+    // FIXME: Investigate whether it would be better to use something like Median of Medians
+    // or Fast Deterministic Selection to guarantee O(n) worst case.
+    let mut limit = usize::BITS - v.len().leading_zeros();
+
+    // True if the last partitioning was reasonably balanced.
+    let mut was_balanced = true;
+
     loop {
         // For slices of up to this length it's probably faster to simply sort them.
         const MAX_INSERTION: usize = 10;
@@ -839,6 +851,18 @@ fn partition_at_index_loop<'a, T, F>(
             return;
         }
 
+        if limit == 0 {
+            heapsort(v, is_less);
+            return;
+        }
+
+        // If the last partitioning was imbalanced, try breaking patterns in the slice by shuffling
+        // some elements around. Hopefully we'll choose a better pivot this time.
+        if !was_balanced {
+            break_patterns(v);
+            limit -= 1;
+        }
+
         // Choose a pivot
         let (pivot, _) = choose_pivot(v, is_less);
 
@@ -863,6 +887,7 @@ fn partition_at_index_loop<'a, T, F>(
         }
 
         let (mid, _) = partition(v, pivot, is_less);
+        was_balanced = cmp::min(mid, v.len() - mid) >= v.len() / 8;
 
         // Split the slice into `left`, `pivot`, and `right`.
         let (left, right) = v.split_at_mut(mid);
@@ -883,6 +908,7 @@ fn partition_at_index_loop<'a, T, F>(
     }
 }
 
+/// Reorder the slice such that the element at `index` is at its final sorted position.
 pub fn partition_at_index<T, F>(
     v: &mut [T],
     index: usize,
@@ -927,3 +953,513 @@ where
     let pivot = &mut pivot[0];
     (left, pivot, right)
 }
+
+/// Inserts `v[0]` into pre-sorted sequence `v[1..]` so that whole `v[..]` becomes sorted.
+///
+/// This is the integral subroutine of insertion sort.
+fn insert_head<T, F>(v: &mut [T], is_less: &mut F)
+where
+    F: FnMut(&T, &T) -> bool,
+{
+    if v.len() >= 2 && is_less(&v[1], &v[0]) {
+        // SAFETY: Copy tmp back even if panic, and ensure unique observation.
+        unsafe {
+            // There are three ways to implement insertion here:
+            //
+            // 1. Swap adjacent elements until the first one gets to its final destination.
+            //    However, this way we copy data around more than is necessary. If elements are big
+            //    structures (costly to copy), this method will be slow.
+            //
+            // 2. Iterate until the right place for the first element is found. Then shift the
+            //    elements succeeding it to make room for it and finally place it into the
+            //    remaining hole. This is a good method.
+            //
+            // 3. Copy the first element into a temporary variable. Iterate until the right place
+            //    for it is found. As we go along, copy every traversed element into the slot
+            //    preceding it. Finally, copy data from the temporary variable into the remaining
+            //    hole. This method is very good. Benchmarks demonstrated slightly better
+            //    performance than with the 2nd method.
+            //
+            // All methods were benchmarked, and the 3rd showed best results. So we chose that one.
+            let tmp = mem::ManuallyDrop::new(ptr::read(&v[0]));
+
+            // Intermediate state of the insertion process is always tracked by `hole`, which
+            // serves two purposes:
+            // 1. Protects integrity of `v` from panics in `is_less`.
+            // 2. Fills the remaining hole in `v` in the end.
+            //
+            // Panic safety:
+            //
+            // If `is_less` panics at any point during the process, `hole` will get dropped and
+            // fill the hole in `v` with `tmp`, thus ensuring that `v` still holds every object it
+            // initially held exactly once.
+            let mut hole = InsertionHole { src: &*tmp, dest: &mut v[1] };
+            ptr::copy_nonoverlapping(&v[1], &mut v[0], 1);
+
+            for i in 2..v.len() {
+                if !is_less(&v[i], &*tmp) {
+                    break;
+                }
+                ptr::copy_nonoverlapping(&v[i], &mut v[i - 1], 1);
+                hole.dest = &mut v[i];
+            }
+            // `hole` gets dropped and thus copies `tmp` into the remaining hole in `v`.
+        }
+    }
+
+    // When dropped, copies from `src` into `dest`.
+    struct InsertionHole<T> {
+        src: *const T,
+        dest: *mut T,
+    }
+
+    impl<T> Drop for InsertionHole<T> {
+        fn drop(&mut self) {
+            // SAFETY: The caller must ensure that src and dest are correctly set.
+            unsafe {
+                ptr::copy_nonoverlapping(self.src, self.dest, 1);
+            }
+        }
+    }
+}
+
+/// Merges non-decreasing runs `v[..mid]` and `v[mid..]` using `buf` as temporary storage, and
+/// stores the result into `v[..]`.
+///
+/// # Safety
+///
+/// The two slices must be non-empty and `mid` must be in bounds. Buffer `buf` must be long enough
+/// to hold a copy of the shorter slice. Also, `T` must not be a zero-sized type.
+unsafe fn merge<T, F>(v: &mut [T], mid: usize, buf: *mut T, is_less: &mut F)
+where
+    F: FnMut(&T, &T) -> bool,
+{
+    let len = v.len();
+    let v = v.as_mut_ptr();
+
+    // SAFETY: mid and len must be in-bounds of v.
+    let (v_mid, v_end) = unsafe { (v.add(mid), v.add(len)) };
+
+    // The merge process first copies the shorter run into `buf`. Then it traces the newly copied
+    // run and the longer run forwards (or backwards), comparing their next unconsumed elements and
+    // copying the lesser (or greater) one into `v`.
+    //
+    // As soon as the shorter run is fully consumed, the process is done. If the longer run gets
+    // consumed first, then we must copy whatever is left of the shorter run into the remaining
+    // hole in `v`.
+    //
+    // Intermediate state of the process is always tracked by `hole`, which serves two purposes:
+    // 1. Protects integrity of `v` from panics in `is_less`.
+    // 2. Fills the remaining hole in `v` if the longer run gets consumed first.
+    //
+    // Panic safety:
+    //
+    // If `is_less` panics at any point during the process, `hole` will get dropped and fill the
+    // hole in `v` with the unconsumed range in `buf`, thus ensuring that `v` still holds every
+    // object it initially held exactly once.
+    let mut hole;
+
+    if mid <= len - mid {
+        // The left run is shorter.
+
+        // SAFETY: buf must have enough capacity for `v[..mid]`.
+        unsafe {
+            ptr::copy_nonoverlapping(v, buf, mid);
+            hole = MergeHole { start: buf, end: buf.add(mid), dest: v };
+        }
+
+        // Initially, these pointers point to the beginnings of their arrays.
+        let left = &mut hole.start;
+        let mut right = v_mid;
+        let out = &mut hole.dest;
+
+        while *left < hole.end && right < v_end {
+            // Consume the lesser side.
+            // If equal, prefer the left run to maintain stability.
+
+            // SAFETY: left and right must be valid and part of v same for out.
+            unsafe {
+                let to_copy = if is_less(&*right, &**left) {
+                    get_and_increment(&mut right)
+                } else {
+                    get_and_increment(left)
+                };
+                ptr::copy_nonoverlapping(to_copy, get_and_increment(out), 1);
+            }
+        }
+    } else {
+        // The right run is shorter.
+
+        // SAFETY: buf must have enough capacity for `v[mid..]`.
+        unsafe {
+            ptr::copy_nonoverlapping(v_mid, buf, len - mid);
+            hole = MergeHole { start: buf, end: buf.add(len - mid), dest: v_mid };
+        }
+
+        // Initially, these pointers point past the ends of their arrays.
+        let left = &mut hole.dest;
+        let right = &mut hole.end;
+        let mut out = v_end;
+
+        while v < *left && buf < *right {
+            // Consume the greater side.
+            // If equal, prefer the right run to maintain stability.
+
+            // SAFETY: left and right must be valid and part of v same for out.
+            unsafe {
+                let to_copy = if is_less(&*right.sub(1), &*left.sub(1)) {
+                    decrement_and_get(left)
+                } else {
+                    decrement_and_get(right)
+                };
+                ptr::copy_nonoverlapping(to_copy, decrement_and_get(&mut out), 1);
+            }
+        }
+    }
+    // Finally, `hole` gets dropped. If the shorter run was not fully consumed, whatever remains of
+    // it will now be copied into the hole in `v`.
+
+    unsafe fn get_and_increment<T>(ptr: &mut *mut T) -> *mut T {
+        let old = *ptr;
+
+        // SAFETY: ptr.add(1) must still be a valid pointer and part of `v`.
+        *ptr = unsafe { ptr.add(1) };
+        old
+    }
+
+    unsafe fn decrement_and_get<T>(ptr: &mut *mut T) -> *mut T {
+        // SAFETY: ptr.sub(1) must still be a valid pointer and part of `v`.
+        *ptr = unsafe { ptr.sub(1) };
+        *ptr
+    }
+
+    // When dropped, copies the range `start..end` into `dest..`.
+    struct MergeHole<T> {
+        start: *mut T,
+        end: *mut T,
+        dest: *mut T,
+    }
+
+    impl<T> Drop for MergeHole<T> {
+        fn drop(&mut self) {
+            // SAFETY: `T` is not a zero-sized type, and these are pointers into a slice's elements.
+            unsafe {
+                let len = self.end.sub_ptr(self.start);
+                ptr::copy_nonoverlapping(self.start, self.dest, len);
+            }
+        }
+    }
+}
+
+/// This merge sort borrows some (but not all) ideas from TimSort, which used to be described in
+/// detail [here](https://github.com/python/cpython/blob/main/Objects/listsort.txt). However Python
+/// has switched to a Powersort based implementation.
+///
+/// The algorithm identifies strictly descending and non-descending subsequences, which are called
+/// natural runs. There is a stack of pending runs yet to be merged. Each newly found run is pushed
+/// onto the stack, and then some pairs of adjacent runs are merged until these two invariants are
+/// satisfied:
+///
+/// 1. for every `i` in `1..runs.len()`: `runs[i - 1].len > runs[i].len`
+/// 2. for every `i` in `2..runs.len()`: `runs[i - 2].len > runs[i - 1].len + runs[i].len`
+///
+/// The invariants ensure that the total running time is *O*(*n* \* log(*n*)) worst-case.
+pub fn merge_sort<T, CmpF, ElemAllocF, ElemDeallocF, RunAllocF, RunDeallocF>(
+    v: &mut [T],
+    is_less: &mut CmpF,
+    elem_alloc_fn: ElemAllocF,
+    elem_dealloc_fn: ElemDeallocF,
+    run_alloc_fn: RunAllocF,
+    run_dealloc_fn: RunDeallocF,
+) where
+    CmpF: FnMut(&T, &T) -> bool,
+    ElemAllocF: Fn(usize) -> *mut T,
+    ElemDeallocF: Fn(*mut T, usize),
+    RunAllocF: Fn(usize) -> *mut TimSortRun,
+    RunDeallocF: Fn(*mut TimSortRun, usize),
+{
+    // Slices of up to this length get sorted using insertion sort.
+    const MAX_INSERTION: usize = 20;
+    // Very short runs are extended using insertion sort to span at least this many elements.
+    const MIN_RUN: usize = 10;
+
+    // The caller should have already checked that.
+    debug_assert!(!T::IS_ZST);
+
+    let len = v.len();
+
+    // Short arrays get sorted in-place via insertion sort to avoid allocations.
+    if len <= MAX_INSERTION {
+        if len >= 2 {
+            for i in (0..len - 1).rev() {
+                insert_head(&mut v[i..], is_less);
+            }
+        }
+        return;
+    }
+
+    // Allocate a buffer to use as scratch memory. We keep the length 0 so we can keep in it
+    // shallow copies of the contents of `v` without risking the dtors running on copies if
+    // `is_less` panics. When merging two sorted runs, this buffer holds a copy of the shorter run,
+    // which will always have length at most `len / 2`.
+    let buf = BufGuard::new(len / 2, elem_alloc_fn, elem_dealloc_fn);
+    let buf_ptr = buf.buf_ptr;
+
+    let mut runs = RunVec::new(run_alloc_fn, run_dealloc_fn);
+
+    // In order to identify natural runs in `v`, we traverse it backwards. That might seem like a
+    // strange decision, but consider the fact that merges more often go in the opposite direction
+    // (forwards). According to benchmarks, merging forwards is slightly faster than merging
+    // backwards. To conclude, identifying runs by traversing backwards improves performance.
+    let mut end = len;
+    while end > 0 {
+        // Find the next natural run, and reverse it if it's strictly descending.
+        let mut start = end - 1;
+        if start > 0 {
+            start -= 1;
+
+            // SAFETY: The v.get_unchecked must be fed with correct inbound indicies.
+            unsafe {
+                if is_less(v.get_unchecked(start + 1), v.get_unchecked(start)) {
+                    while start > 0 && is_less(v.get_unchecked(start), v.get_unchecked(start - 1)) {
+                        start -= 1;
+                    }
+                    v[start..end].reverse();
+                } else {
+                    while start > 0 && !is_less(v.get_unchecked(start), v.get_unchecked(start - 1))
+                    {
+                        start -= 1;
+                    }
+                }
+            }
+        }
+
+        // Insert some more elements into the run if it's too short. Insertion sort is faster than
+        // merge sort on short sequences, so this significantly improves performance.
+        while start > 0 && end - start < MIN_RUN {
+            start -= 1;
+            insert_head(&mut v[start..end], is_less);
+        }
+
+        // Push this run onto the stack.
+        runs.push(TimSortRun { start, len: end - start });
+        end = start;
+
+        // Merge some pairs of adjacent runs to satisfy the invariants.
+        while let Some(r) = collapse(runs.as_slice()) {
+            let left = runs[r + 1];
+            let right = runs[r];
+            // SAFETY: `buf_ptr` must hold enough capacity for the shorter of the two sides, and
+            // neither side may be on length 0.
+            unsafe {
+                merge(&mut v[left.start..right.start + right.len], left.len, buf_ptr, is_less);
+            }
+            runs[r] = TimSortRun { start: left.start, len: left.len + right.len };
+            runs.remove(r + 1);
+        }
+    }
+
+    // Finally, exactly one run must remain in the stack.
+    debug_assert!(runs.len() == 1 && runs[0].start == 0 && runs[0].len == len);
+
+    // Examines the stack of runs and identifies the next pair of runs to merge. More specifically,
+    // if `Some(r)` is returned, that means `runs[r]` and `runs[r + 1]` must be merged next. If the
+    // algorithm should continue building a new run instead, `None` is returned.
+    //
+    // TimSort is infamous for its buggy implementations, as described here:
+    // http://envisage-project.eu/timsort-specification-and-verification/
+    //
+    // The gist of the story is: we must enforce the invariants on the top four runs on the stack.
+    // Enforcing them on just top three is not sufficient to ensure that the invariants will still
+    // hold for *all* runs in the stack.
+    //
+    // This function correctly checks invariants for the top four runs. Additionally, if the top
+    // run starts at index 0, it will always demand a merge operation until the stack is fully
+    // collapsed, in order to complete the sort.
+    #[inline]
+    fn collapse(runs: &[TimSortRun]) -> Option<usize> {
+        let n = runs.len();
+        if n >= 2
+            && (runs[n - 1].start == 0
+                || runs[n - 2].len <= runs[n - 1].len
+                || (n >= 3 && runs[n - 3].len <= runs[n - 2].len + runs[n - 1].len)
+                || (n >= 4 && runs[n - 4].len <= runs[n - 3].len + runs[n - 2].len))
+        {
+            if n >= 3 && runs[n - 3].len < runs[n - 1].len { Some(n - 3) } else { Some(n - 2) }
+        } else {
+            None
+        }
+    }
+
+    // Extremely basic versions of Vec.
+    // Their use is super limited and by having the code here, it allows reuse between the sort
+    // implementations.
+    struct BufGuard<T, ElemDeallocF>
+    where
+        ElemDeallocF: Fn(*mut T, usize),
+    {
+        buf_ptr: *mut T,
+        capacity: usize,
+        elem_dealloc_fn: ElemDeallocF,
+    }
+
+    impl<T, ElemDeallocF> BufGuard<T, ElemDeallocF>
+    where
+        ElemDeallocF: Fn(*mut T, usize),
+    {
+        fn new<ElemAllocF>(
+            len: usize,
+            elem_alloc_fn: ElemAllocF,
+            elem_dealloc_fn: ElemDeallocF,
+        ) -> Self
+        where
+            ElemAllocF: Fn(usize) -> *mut T,
+        {
+            Self { buf_ptr: elem_alloc_fn(len), capacity: len, elem_dealloc_fn }
+        }
+    }
+
+    impl<T, ElemDeallocF> Drop for BufGuard<T, ElemDeallocF>
+    where
+        ElemDeallocF: Fn(*mut T, usize),
+    {
+        fn drop(&mut self) {
+            (self.elem_dealloc_fn)(self.buf_ptr, self.capacity);
+        }
+    }
+
+    struct RunVec<RunAllocF, RunDeallocF>
+    where
+        RunAllocF: Fn(usize) -> *mut TimSortRun,
+        RunDeallocF: Fn(*mut TimSortRun, usize),
+    {
+        buf_ptr: *mut TimSortRun,
+        capacity: usize,
+        len: usize,
+        run_alloc_fn: RunAllocF,
+        run_dealloc_fn: RunDeallocF,
+    }
+
+    impl<RunAllocF, RunDeallocF> RunVec<RunAllocF, RunDeallocF>
+    where
+        RunAllocF: Fn(usize) -> *mut TimSortRun,
+        RunDeallocF: Fn(*mut TimSortRun, usize),
+    {
+        fn new(run_alloc_fn: RunAllocF, run_dealloc_fn: RunDeallocF) -> Self {
+            // Most slices can be sorted with at most 16 runs in-flight.
+            const START_RUN_CAPACITY: usize = 16;
+
+            Self {
+                buf_ptr: run_alloc_fn(START_RUN_CAPACITY),
+                capacity: START_RUN_CAPACITY,
+                len: 0,
+                run_alloc_fn,
+                run_dealloc_fn,
+            }
+        }
+
+        fn push(&mut self, val: TimSortRun) {
+            if self.len == self.capacity {
+                let old_capacity = self.capacity;
+                let old_buf_ptr = self.buf_ptr;
+
+                self.capacity = self.capacity * 2;
+                self.buf_ptr = (self.run_alloc_fn)(self.capacity);
+
+                // SAFETY: buf_ptr new and old were correctly allocated and old_buf_ptr has
+                // old_capacity valid elements.
+                unsafe {
+                    ptr::copy_nonoverlapping(old_buf_ptr, self.buf_ptr, old_capacity);
+                }
+
+                (self.run_dealloc_fn)(old_buf_ptr, old_capacity);
+            }
+
+            // SAFETY: The invariant was just checked.
+            unsafe {
+                self.buf_ptr.add(self.len).write(val);
+            }
+            self.len += 1;
+        }
+
+        fn remove(&mut self, index: usize) {
+            if index >= self.len {
+                panic!("Index out of bounds");
+            }
+
+            // SAFETY: buf_ptr needs to be valid and len invariant upheld.
+            unsafe {
+                // the place we are taking from.
+                let ptr = self.buf_ptr.add(index);
+
+                // Shift everything down to fill in that spot.
+                ptr::copy(ptr.add(1), ptr, self.len - index - 1);
+            }
+            self.len -= 1;
+        }
+
+        fn as_slice(&self) -> &[TimSortRun] {
+            // SAFETY: Safe as long as buf_ptr is valid and len invariant was upheld.
+            unsafe { &*ptr::slice_from_raw_parts(self.buf_ptr, self.len) }
+        }
+
+        fn len(&self) -> usize {
+            self.len
+        }
+    }
+
+    impl<RunAllocF, RunDeallocF> core::ops::Index<usize> for RunVec<RunAllocF, RunDeallocF>
+    where
+        RunAllocF: Fn(usize) -> *mut TimSortRun,
+        RunDeallocF: Fn(*mut TimSortRun, usize),
+    {
+        type Output = TimSortRun;
+
+        fn index(&self, index: usize) -> &Self::Output {
+            if index < self.len {
+                // SAFETY: buf_ptr and len invariant must be upheld.
+                unsafe {
+                    return &*(self.buf_ptr.add(index));
+                }
+            }
+
+            panic!("Index out of bounds");
+        }
+    }
+
+    impl<RunAllocF, RunDeallocF> core::ops::IndexMut<usize> for RunVec<RunAllocF, RunDeallocF>
+    where
+        RunAllocF: Fn(usize) -> *mut TimSortRun,
+        RunDeallocF: Fn(*mut TimSortRun, usize),
+    {
+        fn index_mut(&mut self, index: usize) -> &mut Self::Output {
+            if index < self.len {
+                // SAFETY: buf_ptr and len invariant must be upheld.
+                unsafe {
+                    return &mut *(self.buf_ptr.add(index));
+                }
+            }
+
+            panic!("Index out of bounds");
+        }
+    }
+
+    impl<RunAllocF, RunDeallocF> Drop for RunVec<RunAllocF, RunDeallocF>
+    where
+        RunAllocF: Fn(usize) -> *mut TimSortRun,
+        RunDeallocF: Fn(*mut TimSortRun, usize),
+    {
+        fn drop(&mut self) {
+            // As long as TimSortRun is Copy we don't need to drop them individually but just the
+            // whole allocation.
+            (self.run_dealloc_fn)(self.buf_ptr, self.capacity);
+        }
+    }
+}
+
+/// Internal type used by merge_sort.
+#[derive(Clone, Copy, Debug)]
+pub struct TimSortRun {
+    len: usize,
+    start: usize,
+}
diff --git a/library/core/src/task/wake.rs b/library/core/src/task/wake.rs
index a4425fd234a..89adfccd901 100644
--- a/library/core/src/task/wake.rs
+++ b/library/core/src/task/wake.rs
@@ -174,6 +174,7 @@ impl RawWakerVTable {
 /// Currently, `Context` only serves to provide access to a [`&Waker`](Waker)
 /// which can be used to wake the current task.
 #[stable(feature = "futures_api", since = "1.36.0")]
+#[cfg_attr(not(bootstrap), lang = "Context")]
 pub struct Context<'a> {
     waker: &'a Waker,
     // Ensure we future-proof against variance changes by forcing
diff --git a/library/core/tests/num/dec2flt/mod.rs b/library/core/tests/num/dec2flt/mod.rs
index c4e105cba60..a2b9bb551e6 100644
--- a/library/core/tests/num/dec2flt/mod.rs
+++ b/library/core/tests/num/dec2flt/mod.rs
@@ -15,7 +15,7 @@ macro_rules! test_literal {
         for input in inputs {
             assert_eq!(input.parse(), Ok(x64));
             assert_eq!(input.parse(), Ok(x32));
-            let neg_input = &format!("-{input}");
+            let neg_input = format!("-{input}");
             assert_eq!(neg_input.parse(), Ok(-x64));
             assert_eq!(neg_input.parse(), Ok(-x32));
         }
diff --git a/library/portable-simd/crates/core_simd/examples/spectral_norm.rs b/library/portable-simd/crates/core_simd/examples/spectral_norm.rs
index 012182e090b..d576bd0ccee 100644
--- a/library/portable-simd/crates/core_simd/examples/spectral_norm.rs
+++ b/library/portable-simd/crates/core_simd/examples/spectral_norm.rs
@@ -69,7 +69,7 @@ fn dot(x: &[f64], y: &[f64]) -> f64 {
 #[cfg(test)]
 #[test]
 fn test() {
-    assert_eq!(&format!("{:.9}", spectral_norm(100)), "1.274219991");
+    assert_eq!(format!("{:.9}", spectral_norm(100)), "1.274219991");
 }
 
 fn main() {
diff --git a/library/std/src/io/error/repr_bitpacked.rs b/library/std/src/io/error/repr_bitpacked.rs
index 601c01c2128..3581484050d 100644
--- a/library/std/src/io/error/repr_bitpacked.rs
+++ b/library/std/src/io/error/repr_bitpacked.rs
@@ -374,10 +374,10 @@ static_assert!((TAG_MASK + 1).is_power_of_two());
 static_assert!(align_of::<SimpleMessage>() >= TAG_MASK + 1);
 static_assert!(align_of::<Custom>() >= TAG_MASK + 1);
 
-static_assert!(@usize_eq: (TAG_MASK & TAG_SIMPLE_MESSAGE), TAG_SIMPLE_MESSAGE);
-static_assert!(@usize_eq: (TAG_MASK & TAG_CUSTOM), TAG_CUSTOM);
-static_assert!(@usize_eq: (TAG_MASK & TAG_OS), TAG_OS);
-static_assert!(@usize_eq: (TAG_MASK & TAG_SIMPLE), TAG_SIMPLE);
+static_assert!(@usize_eq: TAG_MASK & TAG_SIMPLE_MESSAGE, TAG_SIMPLE_MESSAGE);
+static_assert!(@usize_eq: TAG_MASK & TAG_CUSTOM, TAG_CUSTOM);
+static_assert!(@usize_eq: TAG_MASK & TAG_OS, TAG_OS);
+static_assert!(@usize_eq: TAG_MASK & TAG_SIMPLE, TAG_SIMPLE);
 
 // This is obviously true (`TAG_CUSTOM` is `0b01`), but in `Repr::new_custom` we
 // offset a pointer by this value, and expect it to both be within the same
diff --git a/library/std/src/io/error/tests.rs b/library/std/src/io/error/tests.rs
index 16c634e9afd..9aea62a5b94 100644
--- a/library/std/src/io/error/tests.rs
+++ b/library/std/src/io/error/tests.rs
@@ -190,5 +190,5 @@ fn test_std_io_error_downcast() {
     let io_error = io_error.downcast::<E>().unwrap_err();
 
     assert_eq!(SIMPLE_MESSAGE.kind, io_error.kind());
-    assert_eq!(SIMPLE_MESSAGE.message, &*format!("{io_error}"));
+    assert_eq!(SIMPLE_MESSAGE.message, format!("{io_error}"));
 }
diff --git a/library/std/src/net/ip_addr/tests.rs b/library/std/src/net/ip_addr/tests.rs
index 7c3430b2b21..0eb59d45de7 100644
--- a/library/std/src/net/ip_addr/tests.rs
+++ b/library/std/src/net/ip_addr/tests.rs
@@ -125,8 +125,8 @@ fn ipv4_addr_to_string() {
     assert_eq!(Ipv4Addr::new(127, 127, 127, 127).to_string(), "127.127.127.127");
 
     // Test padding
-    assert_eq!(&format!("{:16}", Ipv4Addr::new(1, 1, 1, 1)), "1.1.1.1         ");
-    assert_eq!(&format!("{:>16}", Ipv4Addr::new(1, 1, 1, 1)), "         1.1.1.1");
+    assert_eq!(format!("{:16}", Ipv4Addr::new(1, 1, 1, 1)), "1.1.1.1         ");
+    assert_eq!(format!("{:>16}", Ipv4Addr::new(1, 1, 1, 1)), "         1.1.1.1");
 }
 
 #[test]
@@ -148,8 +148,8 @@ fn ipv6_addr_to_string() {
         "1111:2222:3333:4444:5555:6666:7777:8888"
     );
     // padding
-    assert_eq!(&format!("{:20}", Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8)), "1:2:3:4:5:6:7:8     ");
-    assert_eq!(&format!("{:>20}", Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8)), "     1:2:3:4:5:6:7:8");
+    assert_eq!(format!("{:20}", Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8)), "1:2:3:4:5:6:7:8     ");
+    assert_eq!(format!("{:>20}", Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8)), "     1:2:3:4:5:6:7:8");
 
     // reduce a single run of zeros
     assert_eq!(
diff --git a/library/std/src/net/socket_addr/tests.rs b/library/std/src/net/socket_addr/tests.rs
index 15211f81981..dfc6dabbed1 100644
--- a/library/std/src/net/socket_addr/tests.rs
+++ b/library/std/src/net/socket_addr/tests.rs
@@ -64,11 +64,11 @@ fn ipv4_socket_addr_to_string() {
 
     // Test padding.
     assert_eq!(
-        &format!("{:16}", SocketAddrV4::new(Ipv4Addr::new(1, 1, 1, 1), 53)),
+        format!("{:16}", SocketAddrV4::new(Ipv4Addr::new(1, 1, 1, 1), 53)),
         "1.1.1.1:53      "
     );
     assert_eq!(
-        &format!("{:>16}", SocketAddrV4::new(Ipv4Addr::new(1, 1, 1, 1), 53)),
+        format!("{:>16}", SocketAddrV4::new(Ipv4Addr::new(1, 1, 1, 1), 53)),
         "      1.1.1.1:53"
     );
 }
@@ -111,11 +111,11 @@ fn ipv6_socket_addr_to_string() {
 
     // Test padding.
     assert_eq!(
-        &format!("{:22}", SocketAddrV6::new(Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8), 9, 0, 0)),
+        format!("{:22}", SocketAddrV6::new(Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8), 9, 0, 0)),
         "[1:2:3:4:5:6:7:8]:9   "
     );
     assert_eq!(
-        &format!("{:>22}", SocketAddrV6::new(Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8), 9, 0, 0)),
+        format!("{:>22}", SocketAddrV6::new(Ipv6Addr::new(1, 2, 3, 4, 5, 6, 7, 8), 9, 0, 0)),
         "   [1:2:3:4:5:6:7:8]:9"
     );
 }
diff --git a/library/std/src/os/net/linux_ext/addr.rs b/library/std/src/os/net/linux_ext/addr.rs
index df3fc8e6a3b..85065984fbb 100644
--- a/library/std/src/os/net/linux_ext/addr.rs
+++ b/library/std/src/os/net/linux_ext/addr.rs
@@ -38,7 +38,7 @@ pub trait SocketAddrExt: Sealed {
     ///     Ok(())
     /// }
     /// ```
-    fn from_abstract_name<N>(name: &N) -> crate::io::Result<SocketAddr>
+    fn from_abstract_name<N>(name: N) -> crate::io::Result<SocketAddr>
     where
         N: AsRef<[u8]>;
 
diff --git a/library/std/src/os/unix/net/addr.rs b/library/std/src/os/unix/net/addr.rs
index 81ac829d21b..ece2b33bddf 100644
--- a/library/std/src/os/unix/net/addr.rs
+++ b/library/std/src/os/unix/net/addr.rs
@@ -256,7 +256,7 @@ impl linux_ext::addr::SocketAddrExt for SocketAddr {
         if let AddressKind::Abstract(name) = self.address() { Some(name) } else { None }
     }
 
-    fn from_abstract_name<N>(name: &N) -> crate::io::Result<Self>
+    fn from_abstract_name<N>(name: N) -> crate::io::Result<Self>
     where
         N: AsRef<[u8]>,
     {
diff --git a/library/std/src/path.rs b/library/std/src/path.rs
index c3593264e52..2f53cf83936 100644
--- a/library/std/src/path.rs
+++ b/library/std/src/path.rs
@@ -2531,6 +2531,8 @@ impl Path {
 
     /// Creates an owned [`PathBuf`] with `path` adjoined to `self`.
     ///
+    /// If `path` is absolute, it replaces the current path.
+    ///
     /// See [`PathBuf::push`] for more details on what it means to adjoin a path.
     ///
     /// # Examples
@@ -2539,6 +2541,7 @@ impl Path {
     /// use std::path::{Path, PathBuf};
     ///
     /// assert_eq!(Path::new("/etc").join("passwd"), PathBuf::from("/etc/passwd"));
+    /// assert_eq!(Path::new("/etc").join("/bin/sh"), PathBuf::from("/bin/sh"));
     /// ```
     #[stable(feature = "rust1", since = "1.0.0")]
     #[must_use]
diff --git a/library/std/src/sys/unix/process/process_unix.rs b/library/std/src/sys/unix/process/process_unix.rs
index c2c4aa1c9df..3bc17b7754d 100644
--- a/library/std/src/sys/unix/process/process_unix.rs
+++ b/library/std/src/sys/unix/process/process_unix.rs
@@ -746,6 +746,8 @@ fn signal_string(signal: i32) -> &'static str {
         libc::SIGWINCH => " (SIGWINCH)",
         #[cfg(not(target_os = "haiku"))]
         libc::SIGIO => " (SIGIO)",
+        #[cfg(target_os = "haiku")]
+        libc::SIGPOLL => " (SIGPOLL)",
         libc::SIGSYS => " (SIGSYS)",
         // For information on Linux signals, run `man 7 signal`
         #[cfg(all(
diff --git a/src/bootstrap/cc_detect.rs b/src/bootstrap/cc_detect.rs
index 7128d542acf..65c882fb801 100644
--- a/src/bootstrap/cc_detect.rs
+++ b/src/bootstrap/cc_detect.rs
@@ -47,6 +47,8 @@ fn cc2ar(cc: &Path, target: TargetSelection) -> Option<PathBuf> {
         Some(PathBuf::from("ar"))
     } else if target.contains("vxworks") {
         Some(PathBuf::from("wr-ar"))
+    } else if target.contains("android") {
+        Some(cc.parent().unwrap().join(PathBuf::from("llvm-ar")))
     } else {
         let parent = cc.parent().unwrap();
         let file = cc.file_name().unwrap().to_str().unwrap();
@@ -219,12 +221,22 @@ fn set_compiler(
 }
 
 pub(crate) fn ndk_compiler(compiler: Language, triple: &str, ndk: &Path) -> PathBuf {
-    let triple_translated = triple
-        .replace("armv7neon", "arm")
-        .replace("armv7", "arm")
-        .replace("thumbv7neon", "arm")
-        .replace("thumbv7", "arm");
-    let compiler = format!("{}-{}", triple_translated, compiler.clang());
+    let mut triple_iter = triple.split("-");
+    let triple_translated = if let Some(arch) = triple_iter.next() {
+        let arch_new = match arch {
+            "arm" | "armv7" | "armv7neon" | "thumbv7" | "thumbv7neon" => "armv7a",
+            other => other,
+        };
+        std::iter::once(arch_new).chain(triple_iter).collect::<Vec<&str>>().join("-")
+    } else {
+        triple.to_string()
+    };
+
+    // API 19 is the earliest API level supported by NDK r25b but AArch64 and x86_64 support
+    // begins at API level 21.
+    let api_level =
+        if triple.contains("aarch64") || triple.contains("x86_64") { "21" } else { "19" };
+    let compiler = format!("{}{}-{}", triple_translated, api_level, compiler.clang());
     ndk.join("bin").join(compiler)
 }
 
diff --git a/src/bootstrap/dist.rs b/src/bootstrap/dist.rs
index 68215790bed..2e4f753965d 100644
--- a/src/bootstrap/dist.rs
+++ b/src/bootstrap/dist.rs
@@ -1130,12 +1130,6 @@ impl Step for RustAnalyzer {
         let compiler = self.compiler;
         let target = self.target;
 
-        if target.contains("riscv64") {
-            // riscv64 currently has an LLVM bug that makes rust-analyzer unable
-            // to build. See #74813 for details.
-            return None;
-        }
-
         let rust_analyzer = builder
             .ensure(tool::RustAnalyzer { compiler, target })
             .expect("rust-analyzer always builds");
diff --git a/src/bootstrap/native.rs b/src/bootstrap/native.rs
index e0d1504c9c7..cb5706ca0a6 100644
--- a/src/bootstrap/native.rs
+++ b/src/bootstrap/native.rs
@@ -1105,6 +1105,12 @@ fn supported_sanitizers(
         "x86_64-unknown-linux-musl" => {
             common_libs("linux", "x86_64", &["asan", "lsan", "msan", "tsan"])
         }
+        "s390x-unknown-linux-gnu" => {
+            common_libs("linux", "s390x", &["asan", "lsan", "msan", "tsan"])
+        }
+        "s390x-unknown-linux-musl" => {
+            common_libs("linux", "s390x", &["asan", "lsan", "msan", "tsan"])
+        }
         _ => Vec::new(),
     }
 }
diff --git a/src/ci/docker/host-x86_64/arm-android/Dockerfile b/src/ci/docker/host-x86_64/arm-android/Dockerfile
index 7a875c960e1..b6b4fdc67a9 100644
--- a/src/ci/docker/host-x86_64/arm-android/Dockerfile
+++ b/src/ci/docker/host-x86_64/arm-android/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:22.04
+FROM ubuntu:22.10
 
 ARG DEBIAN_FRONTEND=noninteractive
 COPY scripts/android-base-apt-get.sh /scripts/
@@ -6,7 +6,7 @@ RUN sh /scripts/android-base-apt-get.sh
 
 COPY scripts/android-ndk.sh /scripts/
 RUN . /scripts/android-ndk.sh && \
-    download_and_make_toolchain android-ndk-r15c-linux-x86_64.zip arm 14
+    download_ndk android-ndk-r25b-linux.zip
 
 RUN dpkg --add-architecture i386 && \
     apt-get update && \
@@ -30,7 +30,7 @@ ENV PATH=$PATH:/android/sdk/platform-tools
 
 ENV TARGETS=arm-linux-androideabi
 
-ENV RUST_CONFIGURE_ARGS --arm-linux-androideabi-ndk=/android/ndk/arm-14
+ENV RUST_CONFIGURE_ARGS --arm-linux-androideabi-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/
 
 ENV SCRIPT python3 ../x.py --stage 2 test --host='' --target $TARGETS
 
diff --git a/src/ci/docker/host-x86_64/dist-android/Dockerfile b/src/ci/docker/host-x86_64/dist-android/Dockerfile
index 2328db4ab8b..9c6f648896b 100644
--- a/src/ci/docker/host-x86_64/dist-android/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-android/Dockerfile
@@ -1,4 +1,4 @@
-FROM ubuntu:22.04
+FROM ubuntu:22.10
 
 COPY scripts/android-base-apt-get.sh /scripts/
 RUN sh /scripts/android-base-apt-get.sh
@@ -6,14 +6,7 @@ RUN sh /scripts/android-base-apt-get.sh
 # ndk
 COPY scripts/android-ndk.sh /scripts/
 RUN . /scripts/android-ndk.sh && \
-    download_ndk android-ndk-r15c-linux-x86_64.zip && \
-    make_standalone_toolchain arm 14 && \
-    make_standalone_toolchain x86 14 && \
-    make_standalone_toolchain arm 21 && \
-    make_standalone_toolchain x86 21 && \
-    make_standalone_toolchain arm64 21 && \
-    make_standalone_toolchain x86_64 21 && \
-    remove_ndk
+    download_ndk android-ndk-r25b-linux.zip
 
 # env
 ENV TARGETS=arm-linux-androideabi
@@ -26,12 +19,12 @@ ENV TARGETS=$TARGETS,x86_64-linux-android
 ENV RUST_CONFIGURE_ARGS \
       --enable-extended \
       --enable-profiler \
-      --arm-linux-androideabi-ndk=/android/ndk/arm-14 \
-      --armv7-linux-androideabi-ndk=/android/ndk/arm-14 \
-      --thumbv7neon-linux-androideabi-ndk=/android/ndk/arm-14 \
-      --i686-linux-android-ndk=/android/ndk/x86-14 \
-      --aarch64-linux-android-ndk=/android/ndk/arm64-21 \
-      --x86_64-linux-android-ndk=/android/ndk/x86_64-21 \
+      --arm-linux-androideabi-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
+      --armv7-linux-androideabi-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
+      --thumbv7neon-linux-androideabi-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
+      --i686-linux-android-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
+      --aarch64-linux-android-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
+      --x86_64-linux-android-ndk=/android/ndk/toolchains/llvm/prebuilt/linux-x86_64/ \
       --disable-docs
 
 ENV SCRIPT python3 ../x.py dist --host='' --target $TARGETS
diff --git a/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile b/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
index 43a449b3a19..adb98d7ebb5 100644
--- a/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
+++ b/src/ci/docker/host-x86_64/dist-s390x-linux/Dockerfile
@@ -28,5 +28,5 @@ ENV \
 
 ENV HOSTS=s390x-unknown-linux-gnu
 
-ENV RUST_CONFIGURE_ARGS --enable-extended --enable-lld --enable-profiler --disable-docs
+ENV RUST_CONFIGURE_ARGS --enable-extended --enable-lld --enable-sanitizers --enable-profiler --disable-docs
 ENV SCRIPT python3 ../x.py dist --host $HOSTS --target $HOSTS
diff --git a/src/ci/docker/host-x86_64/mingw-check-tidy/Dockerfile b/src/ci/docker/host-x86_64/mingw-check-tidy/Dockerfile
index dc0e591cad6..889a586b351 100644
--- a/src/ci/docker/host-x86_64/mingw-check-tidy/Dockerfile
+++ b/src/ci/docker/host-x86_64/mingw-check-tidy/Dockerfile
@@ -1,8 +1,6 @@
-FROM ubuntu:18.04
-# FIXME: when bumping the version, remove the Python 3.6-specific changes in
-# the reuse-requirements.in file, regenerate reuse-requirements.txt and remove
-# this comment.
+FROM ubuntu:22.04
 
+ARG DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y --no-install-recommends \
   g++ \
   make \
diff --git a/src/ci/docker/host-x86_64/mingw-check/Dockerfile b/src/ci/docker/host-x86_64/mingw-check/Dockerfile
index d5bc76eeb23..4cc5d9f8a0d 100644
--- a/src/ci/docker/host-x86_64/mingw-check/Dockerfile
+++ b/src/ci/docker/host-x86_64/mingw-check/Dockerfile
@@ -1,8 +1,6 @@
-FROM ubuntu:18.04
-# FIXME: when bumping the version, remove the Python 3.6-specific changes in
-# the reuse-requirements.in file, regenerate reuse-requirements.txt and remove
-# this comment.
+FROM ubuntu:22.04
 
+ARG DEBIAN_FRONTEND=noninteractive
 RUN apt-get update && apt-get install -y --no-install-recommends \
   g++ \
   make \
diff --git a/src/ci/docker/host-x86_64/mingw-check/reuse-requirements.in b/src/ci/docker/host-x86_64/mingw-check/reuse-requirements.in
index 4964f40aa39..c7b3376e2f1 100644
--- a/src/ci/docker/host-x86_64/mingw-check/reuse-requirements.in
+++ b/src/ci/docker/host-x86_64/mingw-check/reuse-requirements.in
@@ -12,11 +12,3 @@
 #
 
 reuse
-
-# Some packages dropped support for Python 3.6, which is the version used in
-# this builder (due to Ubuntu 18.04). This should be removed once we bump the
-# Ubuntu version of the builder.
-jinja2 < 3.1
-markupsafe < 2.1
-requests < 2.28
-setuptools < 59.7
diff --git a/src/ci/docker/host-x86_64/mingw-check/reuse-requirements.txt b/src/ci/docker/host-x86_64/mingw-check/reuse-requirements.txt
index 10a5f738790..b0f598f77ea 100644
--- a/src/ci/docker/host-x86_64/mingw-check/reuse-requirements.txt
+++ b/src/ci/docker/host-x86_64/mingw-check/reuse-requirements.txt
@@ -1,6 +1,6 @@
 #
-# This file is autogenerated by pip-compile with python 3.10
-# To update, run:
+# This file is autogenerated by pip-compile with Python 3.10
+# by the following command:
 #
 #    pip-compile --allow-unsafe --generate-hashes reuse-requirements.in
 #
@@ -8,138 +8,77 @@ binaryornot==0.4.4 \
     --hash=sha256:359501dfc9d40632edc9fac890e19542db1a287bbcfa58175b66658392018061 \
     --hash=sha256:b8b71173c917bddcd2c16070412e369c3ed7f0528926f70cac18a6c97fd563e4
     # via reuse
-boolean-py==3.8 \
-    --hash=sha256:cc24e20f985d60cd4a3a5a1c0956dd12611159d32a75081dabd0c9ab981acaa4 \
-    --hash=sha256:d75da0fd0354425fa64f6bbc6cec6ae1485d0eec3447b73187ff8cbf9b572e26
+boolean-py==4.0 \
+    --hash=sha256:17b9a181630e43dde1851d42bef546d616d5d9b4480357514597e78b203d06e4 \
+    --hash=sha256:2876f2051d7d6394a531d82dc6eb407faa0b01a0a0b3083817ccd7323b8d96bd
     # via
     #   license-expression
     #   reuse
-certifi==2022.6.15 \
-    --hash=sha256:84c85a9078b11105f04f3036a9482ae10e4621616db313fe045dd24743a0820d \
-    --hash=sha256:fe86415d55e84719d75f8b69414f6438ac3547d2078ab91b67e779ef69378412
-    # via requests
-chardet==5.0.0 \
-    --hash=sha256:0368df2bfd78b5fc20572bb4e9bb7fb53e2c094f60ae9993339e8671d0afb8aa \
-    --hash=sha256:d3e64f022d254183001eccc5db4040520c0f23b1a3f33d6413e099eb7f126557
+chardet==5.1.0 \
+    --hash=sha256:0d62712b956bc154f85fb0a266e2a3c5913c2967e00348701b32411d6def31e5 \
+    --hash=sha256:362777fb014af596ad31334fde1e8c327dfdb076e1960d1694662d46a6917ab9
     # via
     #   binaryornot
     #   python-debian
-charset-normalizer==2.0.12 \
-    --hash=sha256:2857e29ff0d34db842cd7ca3230549d1a697f96ee6d3fb071cfa6c7393832597 \
-    --hash=sha256:6881edbebdb17b39b4eaaa821b438bf6eddffb4468cf344f09f89def34a8b1df
-    # via requests
-idna==3.3 \
-    --hash=sha256:84d9dd047ffa80596e0f246e2eab0b391788b0503584e8945f2368256d2735ff \
-    --hash=sha256:9d643ff0a55b762d5cdb124b8eaa99c66322e2157b69160bc32796e824360e6d
-    # via requests
-jinja2==3.0.3 \
-    --hash=sha256:077ce6014f7b40d03b47d1f1ca4b0fc8328a692bd284016f806ed0eaca390ad8 \
-    --hash=sha256:611bb273cd68f3b993fabdc4064fc858c5b47a973cb5aa7999ec1ba405c87cd7
-    # via
-    #   -r reuse-requirements.in
-    #   reuse
-license-expression==21.6.14 \
-    --hash=sha256:324246eed8e138b4139fefdc0e9dc4161d5075e3929e56983966d37298dca30e \
-    --hash=sha256:9de87a427c9a449eee7913472fb9ed03b63036295547369fdbf95f76a8b924b2
-    # via
-    #   -r reuse-requirements.in
-    #   reuse
-markupsafe==2.0.1 \
-    --hash=sha256:01a9b8ea66f1658938f65b93a85ebe8bc016e6769611be228d797c9d998dd298 \
-    --hash=sha256:023cb26ec21ece8dc3907c0e8320058b2e0cb3c55cf9564da612bc325bed5e64 \
-    --hash=sha256:0446679737af14f45767963a1a9ef7620189912317d095f2d9ffa183a4d25d2b \
-    --hash=sha256:04635854b943835a6ea959e948d19dcd311762c5c0c6e1f0e16ee57022669194 \
-    --hash=sha256:0717a7390a68be14b8c793ba258e075c6f4ca819f15edfc2a3a027c823718567 \
-    --hash=sha256:0955295dd5eec6cb6cc2fe1698f4c6d84af2e92de33fbcac4111913cd100a6ff \
-    --hash=sha256:0d4b31cc67ab36e3392bbf3862cfbadac3db12bdd8b02a2731f509ed5b829724 \
-    --hash=sha256:10f82115e21dc0dfec9ab5c0223652f7197feb168c940f3ef61563fc2d6beb74 \
-    --hash=sha256:168cd0a3642de83558a5153c8bd34f175a9a6e7f6dc6384b9655d2697312a646 \
-    --hash=sha256:1d609f577dc6e1aa17d746f8bd3c31aa4d258f4070d61b2aa5c4166c1539de35 \
-    --hash=sha256:1f2ade76b9903f39aa442b4aadd2177decb66525062db244b35d71d0ee8599b6 \
-    --hash=sha256:20dca64a3ef2d6e4d5d615a3fd418ad3bde77a47ec8a23d984a12b5b4c74491a \
-    --hash=sha256:2a7d351cbd8cfeb19ca00de495e224dea7e7d919659c2841bbb7f420ad03e2d6 \
-    --hash=sha256:2d7d807855b419fc2ed3e631034685db6079889a1f01d5d9dac950f764da3dad \
-    --hash=sha256:2ef54abee730b502252bcdf31b10dacb0a416229b72c18b19e24a4509f273d26 \
-    --hash=sha256:36bc903cbb393720fad60fc28c10de6acf10dc6cc883f3e24ee4012371399a38 \
-    --hash=sha256:37205cac2a79194e3750b0af2a5720d95f786a55ce7df90c3af697bfa100eaac \
-    --hash=sha256:3c112550557578c26af18a1ccc9e090bfe03832ae994343cfdacd287db6a6ae7 \
-    --hash=sha256:3dd007d54ee88b46be476e293f48c85048603f5f516008bee124ddd891398ed6 \
-    --hash=sha256:4296f2b1ce8c86a6aea78613c34bb1a672ea0e3de9c6ba08a960efe0b0a09047 \
-    --hash=sha256:47ab1e7b91c098ab893b828deafa1203de86d0bc6ab587b160f78fe6c4011f75 \
-    --hash=sha256:49e3ceeabbfb9d66c3aef5af3a60cc43b85c33df25ce03d0031a608b0a8b2e3f \
-    --hash=sha256:4dc8f9fb58f7364b63fd9f85013b780ef83c11857ae79f2feda41e270468dd9b \
-    --hash=sha256:4efca8f86c54b22348a5467704e3fec767b2db12fc39c6d963168ab1d3fc9135 \
-    --hash=sha256:53edb4da6925ad13c07b6d26c2a852bd81e364f95301c66e930ab2aef5b5ddd8 \
-    --hash=sha256:5855f8438a7d1d458206a2466bf82b0f104a3724bf96a1c781ab731e4201731a \
-    --hash=sha256:594c67807fb16238b30c44bdf74f36c02cdf22d1c8cda91ef8a0ed8dabf5620a \
-    --hash=sha256:5b6d930f030f8ed98e3e6c98ffa0652bdb82601e7a016ec2ab5d7ff23baa78d1 \
-    --hash=sha256:5bb28c636d87e840583ee3adeb78172efc47c8b26127267f54a9c0ec251d41a9 \
-    --hash=sha256:60bf42e36abfaf9aff1f50f52644b336d4f0a3fd6d8a60ca0d054ac9f713a864 \
-    --hash=sha256:611d1ad9a4288cf3e3c16014564df047fe08410e628f89805e475368bd304914 \
-    --hash=sha256:6300b8454aa6930a24b9618fbb54b5a68135092bc666f7b06901f897fa5c2fee \
-    --hash=sha256:63f3268ba69ace99cab4e3e3b5840b03340efed0948ab8f78d2fd87ee5442a4f \
-    --hash=sha256:6557b31b5e2c9ddf0de32a691f2312a32f77cd7681d8af66c2692efdbef84c18 \
-    --hash=sha256:693ce3f9e70a6cf7d2fb9e6c9d8b204b6b39897a2c4a1aa65728d5ac97dcc1d8 \
-    --hash=sha256:6a7fae0dd14cf60ad5ff42baa2e95727c3d81ded453457771d02b7d2b3f9c0c2 \
-    --hash=sha256:6c4ca60fa24e85fe25b912b01e62cb969d69a23a5d5867682dd3e80b5b02581d \
-    --hash=sha256:6fcf051089389abe060c9cd7caa212c707e58153afa2c649f00346ce6d260f1b \
-    --hash=sha256:7d91275b0245b1da4d4cfa07e0faedd5b0812efc15b702576d103293e252af1b \
-    --hash=sha256:89c687013cb1cd489a0f0ac24febe8c7a666e6e221b783e53ac50ebf68e45d86 \
-    --hash=sha256:8d206346619592c6200148b01a2142798c989edcb9c896f9ac9722a99d4e77e6 \
-    --hash=sha256:905fec760bd2fa1388bb5b489ee8ee5f7291d692638ea5f67982d968366bef9f \
-    --hash=sha256:97383d78eb34da7e1fa37dd273c20ad4320929af65d156e35a5e2d89566d9dfb \
-    --hash=sha256:984d76483eb32f1bcb536dc27e4ad56bba4baa70be32fa87152832cdd9db0833 \
-    --hash=sha256:99df47edb6bda1249d3e80fdabb1dab8c08ef3975f69aed437cb69d0a5de1e28 \
-    --hash=sha256:9f02365d4e99430a12647f09b6cc8bab61a6564363f313126f775eb4f6ef798e \
-    --hash=sha256:a30e67a65b53ea0a5e62fe23682cfe22712e01f453b95233b25502f7c61cb415 \
-    --hash=sha256:ab3ef638ace319fa26553db0624c4699e31a28bb2a835c5faca8f8acf6a5a902 \
-    --hash=sha256:aca6377c0cb8a8253e493c6b451565ac77e98c2951c45f913e0b52facdcff83f \
-    --hash=sha256:add36cb2dbb8b736611303cd3bfcee00afd96471b09cda130da3581cbdc56a6d \
-    --hash=sha256:b2f4bf27480f5e5e8ce285a8c8fd176c0b03e93dcc6646477d4630e83440c6a9 \
-    --hash=sha256:b7f2d075102dc8c794cbde1947378051c4e5180d52d276987b8d28a3bd58c17d \
-    --hash=sha256:baa1a4e8f868845af802979fcdbf0bb11f94f1cb7ced4c4b8a351bb60d108145 \
-    --hash=sha256:be98f628055368795d818ebf93da628541e10b75b41c559fdf36d104c5787066 \
-    --hash=sha256:bf5d821ffabf0ef3533c39c518f3357b171a1651c1ff6827325e4489b0e46c3c \
-    --hash=sha256:c47adbc92fc1bb2b3274c4b3a43ae0e4573d9fbff4f54cd484555edbf030baf1 \
-    --hash=sha256:cdfba22ea2f0029c9261a4bd07e830a8da012291fbe44dc794e488b6c9bb353a \
-    --hash=sha256:d6c7ebd4e944c85e2c3421e612a7057a2f48d478d79e61800d81468a8d842207 \
-    --hash=sha256:d7f9850398e85aba693bb640262d3611788b1f29a79f0c93c565694658f4071f \
-    --hash=sha256:d8446c54dc28c01e5a2dbac5a25f071f6653e6e40f3a8818e8b45d790fe6ef53 \
-    --hash=sha256:deb993cacb280823246a026e3b2d81c493c53de6acfd5e6bfe31ab3402bb37dd \
-    --hash=sha256:e0f138900af21926a02425cf736db95be9f4af72ba1bb21453432a07f6082134 \
-    --hash=sha256:e9936f0b261d4df76ad22f8fee3ae83b60d7c3e871292cd42f40b81b70afae85 \
-    --hash=sha256:f0567c4dc99f264f49fe27da5f735f414c4e7e7dd850cfd8e69f0862d7c74ea9 \
-    --hash=sha256:f5653a225f31e113b152e56f154ccbe59eeb1c7487b39b9d9f9cdb58e6c79dc5 \
-    --hash=sha256:f826e31d18b516f653fe296d967d700fddad5901ae07c622bb3705955e1faa94 \
-    --hash=sha256:f8ba0e8349a38d3001fae7eadded3f6606f0da5d748ee53cc1dab1d6527b9509 \
-    --hash=sha256:f9081981fe268bd86831e5c75f7de206ef275defcb82bc70740ae6dc507aee51 \
-    --hash=sha256:fa130dd50c57d53368c9d59395cb5526eda596d3ffe36666cd81a44d56e48872
-    # via
-    #   -r reuse-requirements.in
-    #   jinja2
-python-debian==0.1.44 \
-    --hash=sha256:11bd6f01c46da57982bdd66dd595e2d240feb32a85de3fd37c452102fd0337ab \
-    --hash=sha256:65592fe3b64f6c6c93d94e2d2599db5e0c22831d3bcff07cb7b96d3840b1333e
+jinja2==3.1.2 \
+    --hash=sha256:31351a702a408a9e7595a8fc6150fc3f43bb6bf7e319770cbc0db9df9437e852 \
+    --hash=sha256:6088930bfe239f0e6710546ab9c19c9ef35e29792895fed6e6e31a023a182a61
     # via reuse
-requests==2.26.0 \
-    --hash=sha256:6c1246513ecd5ecd4528a0906f910e8f0f9c6b8ec72030dc9fd154dc1a6efd24 \
-    --hash=sha256:b8aa58f8cf793ffd8782d3d8cb19e66ef36f7aba4353eec859e74678b01b07a7
-    # via
-    #   -r reuse-requirements.in
-    #   reuse
-reuse==1.0.0 \
-    --hash=sha256:db3022be2d87f69c8f508b928023de3026f454ce17d01e22f770f7147ac1e8d4 \
-    --hash=sha256:e2605e796311c424465d741ea2a1e1ad03bbb90b921d74750119c331ca5af46e
+license-expression==30.0.0 \
+    --hash=sha256:ad638292aa8493f84354909b517922cb823582c2ce2c4d880e42544a86bea8dd \
+    --hash=sha256:e95325110110eb2b7539ee7773b97a0724d5371ec563cc718c8cac0e38cc40cc
+    # via reuse
+markupsafe==2.1.1 \
+    --hash=sha256:0212a68688482dc52b2d45013df70d169f542b7394fc744c02a57374a4207003 \
+    --hash=sha256:089cf3dbf0cd6c100f02945abeb18484bd1ee57a079aefd52cffd17fba910b88 \
+    --hash=sha256:10c1bfff05d95783da83491be968e8fe789263689c02724e0c691933c52994f5 \
+    --hash=sha256:33b74d289bd2f5e527beadcaa3f401e0df0a89927c1559c8566c066fa4248ab7 \
+    --hash=sha256:3799351e2336dc91ea70b034983ee71cf2f9533cdff7c14c90ea126bfd95d65a \
+    --hash=sha256:3ce11ee3f23f79dbd06fb3d63e2f6af7b12db1d46932fe7bd8afa259a5996603 \
+    --hash=sha256:421be9fbf0ffe9ffd7a378aafebbf6f4602d564d34be190fc19a193232fd12b1 \
+    --hash=sha256:43093fb83d8343aac0b1baa75516da6092f58f41200907ef92448ecab8825135 \
+    --hash=sha256:46d00d6cfecdde84d40e572d63735ef81423ad31184100411e6e3388d405e247 \
+    --hash=sha256:4a33dea2b688b3190ee12bd7cfa29d39c9ed176bda40bfa11099a3ce5d3a7ac6 \
+    --hash=sha256:4b9fe39a2ccc108a4accc2676e77da025ce383c108593d65cc909add5c3bd601 \
+    --hash=sha256:56442863ed2b06d19c37f94d999035e15ee982988920e12a5b4ba29b62ad1f77 \
+    --hash=sha256:671cd1187ed5e62818414afe79ed29da836dde67166a9fac6d435873c44fdd02 \
+    --hash=sha256:694deca8d702d5db21ec83983ce0bb4b26a578e71fbdbd4fdcd387daa90e4d5e \
+    --hash=sha256:6a074d34ee7a5ce3effbc526b7083ec9731bb3cbf921bbe1d3005d4d2bdb3a63 \
+    --hash=sha256:6d0072fea50feec76a4c418096652f2c3238eaa014b2f94aeb1d56a66b41403f \
+    --hash=sha256:6fbf47b5d3728c6aea2abb0589b5d30459e369baa772e0f37a0320185e87c980 \
+    --hash=sha256:7f91197cc9e48f989d12e4e6fbc46495c446636dfc81b9ccf50bb0ec74b91d4b \
+    --hash=sha256:86b1f75c4e7c2ac2ccdaec2b9022845dbb81880ca318bb7a0a01fbf7813e3812 \
+    --hash=sha256:8dc1c72a69aa7e082593c4a203dcf94ddb74bb5c8a731e4e1eb68d031e8498ff \
+    --hash=sha256:8e3dcf21f367459434c18e71b2a9532d96547aef8a871872a5bd69a715c15f96 \
+    --hash=sha256:8e576a51ad59e4bfaac456023a78f6b5e6e7651dcd383bcc3e18d06f9b55d6d1 \
+    --hash=sha256:96e37a3dc86e80bf81758c152fe66dbf60ed5eca3d26305edf01892257049925 \
+    --hash=sha256:97a68e6ada378df82bc9f16b800ab77cbf4b2fada0081794318520138c088e4a \
+    --hash=sha256:99a2a507ed3ac881b975a2976d59f38c19386d128e7a9a18b7df6fff1fd4c1d6 \
+    --hash=sha256:a49907dd8420c5685cfa064a1335b6754b74541bbb3706c259c02ed65b644b3e \
+    --hash=sha256:b09bf97215625a311f669476f44b8b318b075847b49316d3e28c08e41a7a573f \
+    --hash=sha256:b7bd98b796e2b6553da7225aeb61f447f80a1ca64f41d83612e6139ca5213aa4 \
+    --hash=sha256:b87db4360013327109564f0e591bd2a3b318547bcef31b468a92ee504d07ae4f \
+    --hash=sha256:bcb3ed405ed3222f9904899563d6fc492ff75cce56cba05e32eff40e6acbeaa3 \
+    --hash=sha256:d4306c36ca495956b6d568d276ac11fdd9c30a36f1b6eb928070dc5360b22e1c \
+    --hash=sha256:d5ee4f386140395a2c818d149221149c54849dfcfcb9f1debfe07a8b8bd63f9a \
+    --hash=sha256:dda30ba7e87fbbb7eab1ec9f58678558fd9a6b8b853530e176eabd064da81417 \
+    --hash=sha256:e04e26803c9c3851c931eac40c695602c6295b8d432cbe78609649ad9bd2da8a \
+    --hash=sha256:e1c0b87e09fa55a220f058d1d49d3fb8df88fbfab58558f1198e08c1e1de842a \
+    --hash=sha256:e72591e9ecd94d7feb70c1cbd7be7b3ebea3f548870aa91e2732960fa4d57a37 \
+    --hash=sha256:e8c843bbcda3a2f1e3c2ab25913c80a3c5376cd00c6e8c4a86a89a28c8dc5452 \
+    --hash=sha256:efc1913fd2ca4f334418481c7e595c00aad186563bbc1ec76067848c7ca0a933 \
+    --hash=sha256:f121a1420d4e173a5d96e47e9a0c0dcff965afdf1626d28de1460815f7c4ee7a \
+    --hash=sha256:fc7b548b17d238737688817ab67deebb30e8073c95749d55538ed473130ec0c7
+    # via jinja2
+python-debian==0.1.49 \
+    --hash=sha256:880f3bc52e31599f2a9b432bd7691844286825087fccdcf2f6ffd5cd79a26f9f \
+    --hash=sha256:8cf677a30dbcb4be7a99536c17e11308a827a4d22028dc59a67f6c6dd3f0f58c
+    # via reuse
+reuse==1.1.0 \
+    --hash=sha256:7a054f6e372ad02d0b1b07368030fc38746b50ed45f5422a81994e7a88b52f1f \
+    --hash=sha256:b0f3fb9091ff513af04b555d14a4c529ab05f6a575ab192dd9b68244f1e0721d
     # via -r reuse-requirements.in
-urllib3==1.26.10 \
-    --hash=sha256:8298d6d56d39be0e3bc13c1c97d133f9b45d797169a0e11cdd0e0489d786f7ec \
-    --hash=sha256:879ba4d1e89654d9769ce13121e0f94310ea32e8d2f8cf587b77c08bbcdb30d6
-    # via requests
-
-# The following packages are considered to be unsafe in a requirements file:
-setuptools==59.6.0 \
-    --hash=sha256:22c7348c6d2976a52632c67f7ab0cdf40147db7789f9aed18734643fe9cf3373 \
-    --hash=sha256:4ce92f1e1f8f01233ee9952c04f6b81d1e02939d6e1b488428154974a4d0783e
-    # via
-    #   -r reuse-requirements.in
-    #   reuse
+setuptools==66.0.0 \
+    --hash=sha256:a78d01d1e2c175c474884671dde039962c9d74c7223db7369771fcf6e29ceeab \
+    --hash=sha256:bd6eb2d6722568de6d14b87c44a96fac54b2a45ff5e940e639979a3d1792adb6
+    # via reuse
diff --git a/src/ci/docker/scripts/android-ndk.sh b/src/ci/docker/scripts/android-ndk.sh
index ba70c62ea30..4dd6ac274fd 100644
--- a/src/ci/docker/scripts/android-ndk.sh
+++ b/src/ci/docker/scripts/android-ndk.sh
@@ -4,28 +4,10 @@ set -ex
 URL=https://dl.google.com/android/repository
 
 download_ndk() {
-    mkdir -p /android/ndk
-    cd /android/ndk
+    mkdir /android/
+    cd /android
     curl -fO $URL/$1
     unzip -q $1
     rm $1
     mv android-ndk-* ndk
 }
-
-make_standalone_toolchain() {
-    # See https://developer.android.com/ndk/guides/standalone_toolchain.htm
-    python3 /android/ndk/ndk/build/tools/make_standalone_toolchain.py \
-        --install-dir /android/ndk/$1-$2 \
-        --arch $1 \
-        --api $2
-}
-
-remove_ndk() {
-    rm -rf /android/ndk/ndk
-}
-
-download_and_make_toolchain() {
-    download_ndk $1 && \
-    make_standalone_toolchain $2 $3 && \
-    remove_ndk
-}
diff --git a/src/doc/book b/src/doc/book
-Subproject 2bd5d42c9956369132228da6409f0e68da56c51
+Subproject 2cd1b5593d26dc6a03c20f8619187ad4b248555
diff --git a/src/doc/nomicon b/src/doc/nomicon
-Subproject 8ca261268068d80c0969260fff15199bad87b58
+Subproject 960d610e7f33889a2577f5f17c26f0d5c82b30d
diff --git a/src/doc/reference b/src/doc/reference
-Subproject 3ae62681ff236d5528ef7c8c28ba7c6b2ecc673
+Subproject 2cb0ed9ba56360949f492f9866afe8c293f9f9d
diff --git a/src/doc/rust-by-example b/src/doc/rust-by-example
-Subproject 8888f9428fe9a48f31de6bd2cef9b9bf80791ed
+Subproject a9fb7d13eadfcc5f457962731f105b97f9a7474
diff --git a/src/doc/rustc-dev-guide b/src/doc/rustc-dev-guide
-Subproject b3e2a6e6c8a3aae5b5d950c63046f23bae07096
+Subproject 7352353ae91c48b136d2ca7d03822e1448165e1
diff --git a/src/doc/rustc/src/instrument-coverage.md b/src/doc/rustc/src/instrument-coverage.md
index 38fd5c96997..da91e25595c 100644
--- a/src/doc/rustc/src/instrument-coverage.md
+++ b/src/doc/rustc/src/instrument-coverage.md
@@ -201,6 +201,8 @@ $ RUSTFLAGS="-C instrument-coverage" \
     cargo test --tests
 ```
 
+> **Note**: The default for `LLVM_PROFILE_FILE` is `default_%m_%p.profraw`. Versions prior to 1.65 had a default of `default.profraw`, so if using those earlier versions, it is recommended to explicitly set `LLVM_PROFILE_FILE="default_%m_%p.profraw"` to avoid having multiple tests overwrite the `.profraw` files.
+
 Make note of the test binary file paths, displayed after the word "`Running`" in the test output:
 
 ```text
diff --git a/src/librustdoc/clean/auto_trait.rs b/src/librustdoc/clean/auto_trait.rs
index 4d6f1524732..a302750aa1a 100644
--- a/src/librustdoc/clean/auto_trait.rs
+++ b/src/librustdoc/clean/auto_trait.rs
@@ -402,15 +402,13 @@ where
                     bound_params: Vec::new(),
                 })
             })
-            .chain(
-                lifetime_to_bounds.into_iter().filter(|&(_, ref bounds)| !bounds.is_empty()).map(
-                    |(lifetime, bounds)| {
-                        let mut bounds_vec = bounds.into_iter().collect();
-                        self.sort_where_bounds(&mut bounds_vec);
-                        WherePredicate::RegionPredicate { lifetime, bounds: bounds_vec }
-                    },
-                ),
-            )
+            .chain(lifetime_to_bounds.into_iter().filter(|(_, bounds)| !bounds.is_empty()).map(
+                |(lifetime, bounds)| {
+                    let mut bounds_vec = bounds.into_iter().collect();
+                    self.sort_where_bounds(&mut bounds_vec);
+                    WherePredicate::RegionPredicate { lifetime, bounds: bounds_vec }
+                },
+            ))
             .collect()
     }
 
diff --git a/src/librustdoc/clean/inline.rs b/src/librustdoc/clean/inline.rs
index c6939326144..da300b89a4e 100644
--- a/src/librustdoc/clean/inline.rs
+++ b/src/librustdoc/clean/inline.rs
@@ -9,7 +9,7 @@ use rustc_ast as ast;
 use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::{DefId, DefIdSet, LocalDefId};
 use rustc_hir::Mutability;
 use rustc_metadata::creader::{CStore, LoadedMacro};
 use rustc_middle::ty::{self, TyCtxt};
@@ -45,7 +45,7 @@ pub(crate) fn try_inline(
     res: Res,
     name: Symbol,
     attrs: Option<&[ast::Attribute]>,
-    visited: &mut FxHashSet<DefId>,
+    visited: &mut DefIdSet,
 ) -> Option<Vec<clean::Item>> {
     let did = res.opt_def_id()?;
     if did.is_local() {
@@ -162,7 +162,8 @@ pub(crate) fn try_inline(
 pub(crate) fn try_inline_glob(
     cx: &mut DocContext<'_>,
     res: Res,
-    visited: &mut FxHashSet<DefId>,
+    current_mod: LocalDefId,
+    visited: &mut DefIdSet,
     inlined_names: &mut FxHashSet<(ItemType, Symbol)>,
 ) -> Option<Vec<clean::Item>> {
     let did = res.opt_def_id()?;
@@ -172,7 +173,16 @@ pub(crate) fn try_inline_glob(
 
     match res {
         Res::Def(DefKind::Mod, did) => {
-            let mut items = build_module_items(cx, did, visited, inlined_names);
+            // Use the set of module reexports to filter away names that are not actually
+            // reexported by the glob, e.g. because they are shadowed by something else.
+            let reexports = cx
+                .tcx
+                .module_reexports(current_mod)
+                .unwrap_or_default()
+                .iter()
+                .filter_map(|child| child.res.opt_def_id())
+                .collect();
+            let mut items = build_module_items(cx, did, visited, inlined_names, Some(&reexports));
             items.drain_filter(|item| {
                 if let Some(name) = item.name {
                     // If an item with the same type and name already exists,
@@ -558,12 +568,8 @@ pub(crate) fn build_impl(
     ));
 }
 
-fn build_module(
-    cx: &mut DocContext<'_>,
-    did: DefId,
-    visited: &mut FxHashSet<DefId>,
-) -> clean::Module {
-    let items = build_module_items(cx, did, visited, &mut FxHashSet::default());
+fn build_module(cx: &mut DocContext<'_>, did: DefId, visited: &mut DefIdSet) -> clean::Module {
+    let items = build_module_items(cx, did, visited, &mut FxHashSet::default(), None);
 
     let span = clean::Span::new(cx.tcx.def_span(did));
     clean::Module { items, span }
@@ -572,8 +578,9 @@ fn build_module(
 fn build_module_items(
     cx: &mut DocContext<'_>,
     did: DefId,
-    visited: &mut FxHashSet<DefId>,
+    visited: &mut DefIdSet,
     inlined_names: &mut FxHashSet<(ItemType, Symbol)>,
+    allowed_def_ids: Option<&DefIdSet>,
 ) -> Vec<clean::Item> {
     let mut items = Vec::new();
 
@@ -583,6 +590,11 @@ fn build_module_items(
     for &item in cx.tcx.module_children(did).iter() {
         if item.vis.is_public() {
             let res = item.res.expect_non_local();
+            if let Some(def_id) = res.opt_def_id()
+                && let Some(allowed_def_ids) = allowed_def_ids
+                && !allowed_def_ids.contains(&def_id) {
+                continue;
+            }
             if let Some(def_id) = res.mod_def_id() {
                 // If we're inlining a glob import, it's possible to have
                 // two distinct modules with the same name. We don't want to
diff --git a/src/librustdoc/clean/mod.rs b/src/librustdoc/clean/mod.rs
index 415e7d5a360..34a7068e5da 100644
--- a/src/librustdoc/clean/mod.rs
+++ b/src/librustdoc/clean/mod.rs
@@ -15,7 +15,7 @@ use rustc_attr as attr;
 use rustc_data_structures::fx::{FxHashMap, FxHashSet, FxIndexMap, FxIndexSet, IndexEntry};
 use rustc_hir as hir;
 use rustc_hir::def::{CtorKind, DefKind, Res};
-use rustc_hir::def_id::{DefId, LOCAL_CRATE};
+use rustc_hir::def_id::{DefId, DefIdMap, DefIdSet, LOCAL_CRATE};
 use rustc_hir::PredicateOrigin;
 use rustc_hir_analysis::hir_ty_to_ty;
 use rustc_infer::infer::region_constraints::{Constraint, RegionConstraintData};
@@ -1528,7 +1528,7 @@ fn maybe_expand_private_type_alias<'tcx>(
     let hir::ItemKind::TyAlias(ty, generics) = alias else { return None };
 
     let provided_params = &path.segments.last().expect("segments were empty");
-    let mut substs = FxHashMap::default();
+    let mut substs = DefIdMap::default();
     let generic_args = provided_params.args();
 
     let mut indices: hir::GenericParamCount = Default::default();
@@ -2321,7 +2321,7 @@ fn clean_extern_crate<'tcx>(
 
     let krate_owner_def_id = krate.owner_id.to_def_id();
     if please_inline {
-        let mut visited = FxHashSet::default();
+        let mut visited = DefIdSet::default();
 
         let res = Res::Def(DefKind::Mod, crate_def_id);
 
@@ -2440,8 +2440,9 @@ fn clean_use_statement_inner<'tcx>(
     let path = clean_path(path, cx);
     let inner = if kind == hir::UseKind::Glob {
         if !denied {
-            let mut visited = FxHashSet::default();
-            if let Some(items) = inline::try_inline_glob(cx, path.res, &mut visited, inlined_names)
+            let mut visited = DefIdSet::default();
+            if let Some(items) =
+                inline::try_inline_glob(cx, path.res, current_mod, &mut visited, inlined_names)
             {
                 return items;
             }
@@ -2458,7 +2459,7 @@ fn clean_use_statement_inner<'tcx>(
             }
         }
         if !denied {
-            let mut visited = FxHashSet::default();
+            let mut visited = DefIdSet::default();
             let import_def_id = import.owner_id.to_def_id();
 
             if let Some(mut items) = inline::try_inline(
diff --git a/src/librustdoc/clean/simplify.rs b/src/librustdoc/clean/simplify.rs
index e96a9bab726..dbbc25739aa 100644
--- a/src/librustdoc/clean/simplify.rs
+++ b/src/librustdoc/clean/simplify.rs
@@ -46,7 +46,7 @@ pub(crate) fn where_clauses(cx: &DocContext<'_>, clauses: Vec<WP>) -> ThinVec<WP
 
     // Look for equality predicates on associated types that can be merged into
     // general bound predicates.
-    equalities.retain(|&(ref lhs, ref rhs, ref bound_params)| {
+    equalities.retain(|(lhs, rhs, bound_params)| {
         let Some((ty, trait_did, name)) = lhs.projection() else { return true; };
         let Some((bounds, _)) = tybounds.get_mut(ty) else { return true };
         let bound_params = bound_params
diff --git a/src/librustdoc/core.rs b/src/librustdoc/core.rs
index da0df596c41..10b606f425e 100644
--- a/src/librustdoc/core.rs
+++ b/src/librustdoc/core.rs
@@ -6,7 +6,7 @@ use rustc_errors::emitter::{Emitter, EmitterWriter};
 use rustc_errors::json::JsonEmitter;
 use rustc_feature::UnstableFeatures;
 use rustc_hir::def::{Namespace, Res};
-use rustc_hir::def_id::{DefId, DefIdMap, LocalDefId};
+use rustc_hir::def_id::{DefId, DefIdMap, DefIdSet, LocalDefId};
 use rustc_hir::intravisit::{self, Visitor};
 use rustc_hir::{HirId, Path, TraitCandidate};
 use rustc_interface::interface;
@@ -60,11 +60,11 @@ pub(crate) struct DocContext<'tcx> {
     pub(crate) external_traits: Rc<RefCell<FxHashMap<DefId, clean::Trait>>>,
     /// Used while populating `external_traits` to ensure we don't process the same trait twice at
     /// the same time.
-    pub(crate) active_extern_traits: FxHashSet<DefId>,
+    pub(crate) active_extern_traits: DefIdSet,
     // The current set of parameter substitutions,
     // for expanding type aliases at the HIR level:
     /// Table `DefId` of type, lifetime, or const parameter -> substituted type, lifetime, or const
-    pub(crate) substs: FxHashMap<DefId, clean::SubstParam>,
+    pub(crate) substs: DefIdMap<clean::SubstParam>,
     /// Table synthetic type parameter for `impl Trait` in argument position -> bounds
     pub(crate) impl_trait_bounds: FxHashMap<ImplTraitParam, Vec<clean::GenericBound>>,
     /// Auto-trait or blanket impls processed so far, as `(self_ty, trait_def_id)`.
@@ -108,11 +108,7 @@ impl<'tcx> DocContext<'tcx> {
 
     /// Call the closure with the given parameters set as
     /// the substitutions for a type alias' RHS.
-    pub(crate) fn enter_alias<F, R>(
-        &mut self,
-        substs: FxHashMap<DefId, clean::SubstParam>,
-        f: F,
-    ) -> R
+    pub(crate) fn enter_alias<F, R>(&mut self, substs: DefIdMap<clean::SubstParam>, f: F) -> R
     where
         F: FnOnce(&mut Self) -> R,
     {
@@ -225,7 +221,6 @@ pub(crate) fn create_config(
     // Add the doc cfg into the doc build.
     cfgs.push("doc".to_string());
 
-    let cpath = Some(input.clone());
     let input = Input::File(input);
 
     // By default, rustdoc ignores all lints.
@@ -277,7 +272,6 @@ pub(crate) fn create_config(
         crate_cfg: interface::parse_cfgspecs(cfgs),
         crate_check_cfg: interface::parse_check_cfg(check_cfgs),
         input,
-        input_path: cpath,
         output_file: None,
         output_dir: None,
         file_loader: None,
diff --git a/src/librustdoc/doctest.rs b/src/librustdoc/doctest.rs
index d1b6d470e86..c1a652c75f4 100644
--- a/src/librustdoc/doctest.rs
+++ b/src/librustdoc/doctest.rs
@@ -95,7 +95,6 @@ pub(crate) fn run(options: RustdocOptions) -> Result<(), ErrorGuaranteed> {
         crate_cfg: interface::parse_cfgspecs(cfgs),
         crate_check_cfg: interface::parse_check_cfg(options.check_cfgs.clone()),
         input,
-        input_path: None,
         output_file: None,
         output_dir: None,
         file_loader: None,
diff --git a/src/librustdoc/formats/cache.rs b/src/librustdoc/formats/cache.rs
index 3149c22b8e5..24752cddb33 100644
--- a/src/librustdoc/formats/cache.rs
+++ b/src/librustdoc/formats/cache.rs
@@ -1,7 +1,7 @@
 use std::mem;
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_hir::def_id::{CrateNum, DefId};
+use rustc_hir::def_id::{CrateNum, DefId, DefIdMap, DefIdSet};
 use rustc_middle::ty::{self, TyCtxt};
 use rustc_span::Symbol;
 
@@ -33,7 +33,7 @@ pub(crate) struct Cache {
     ///
     /// The values of the map are a list of implementations and documentation
     /// found on that implementation.
-    pub(crate) impls: FxHashMap<DefId, Vec<Impl>>,
+    pub(crate) impls: DefIdMap<Vec<Impl>>,
 
     /// Maintains a mapping of local crate `DefId`s to the fully qualified name
     /// and "short type description" of that node. This is used when generating
@@ -56,7 +56,7 @@ pub(crate) struct Cache {
     /// to the path used if the corresponding type is inlined. By
     /// doing this, we can detect duplicate impls on a trait page, and only display
     /// the impl for the inlined type.
-    pub(crate) exact_paths: FxHashMap<DefId, Vec<Symbol>>,
+    pub(crate) exact_paths: DefIdMap<Vec<Symbol>>,
 
     /// This map contains information about all known traits of this crate.
     /// Implementations of a crate should inherit the documentation of the
@@ -127,7 +127,7 @@ pub(crate) struct Cache {
 struct CacheBuilder<'a, 'tcx> {
     cache: &'a mut Cache,
     /// This field is used to prevent duplicated impl blocks.
-    impl_ids: FxHashMap<DefId, FxHashSet<DefId>>,
+    impl_ids: DefIdMap<DefIdSet>,
     tcx: TyCtxt<'tcx>,
 }
 
@@ -173,7 +173,7 @@ impl Cache {
 
         let (krate, mut impl_ids) = {
             let mut cache_builder =
-                CacheBuilder { tcx, cache: &mut cx.cache, impl_ids: FxHashMap::default() };
+                CacheBuilder { tcx, cache: &mut cx.cache, impl_ids: Default::default() };
             krate = cache_builder.fold_crate(krate);
             (krate, cache_builder.impl_ids)
         };
@@ -296,7 +296,7 @@ impl<'a, 'tcx> DocFolder for CacheBuilder<'a, 'tcx> {
                             // for where the type was defined. On the other
                             // hand, `paths` always has the right
                             // information if present.
-                            Some(&(ref fqp, _)) => Some(&fqp[..fqp.len() - 1]),
+                            Some((fqp, _)) => Some(&fqp[..fqp.len() - 1]),
                             None => None,
                         };
                         ((did, path), true)
diff --git a/src/librustdoc/html/format.rs b/src/librustdoc/html/format.rs
index 006076baf72..d3dc4065dfc 100644
--- a/src/librustdoc/html/format.rs
+++ b/src/librustdoc/html/format.rs
@@ -962,7 +962,7 @@ fn fmt_type<'cx>(
         clean::Tuple(ref typs) => {
             match &typs[..] {
                 &[] => primitive_link(f, PrimitiveType::Unit, "()", cx),
-                &[ref one] => {
+                [one] => {
                     if let clean::Generic(name) = one {
                         primitive_link(f, PrimitiveType::Tuple, &format!("({name},)"), cx)
                     } else {
diff --git a/src/librustdoc/html/render/context.rs b/src/librustdoc/html/render/context.rs
index 5cefe9475e7..15258a467a2 100644
--- a/src/librustdoc/html/render/context.rs
+++ b/src/librustdoc/html/render/context.rs
@@ -6,7 +6,7 @@ use std::rc::Rc;
 use std::sync::mpsc::{channel, Receiver};
 
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_hir::def_id::{DefId, LOCAL_CRATE};
+use rustc_hir::def_id::{DefIdMap, LOCAL_CRATE};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_span::edition::Edition;
@@ -56,7 +56,7 @@ pub(crate) struct Context<'tcx> {
     pub(super) render_redirect_pages: bool,
     /// Tracks section IDs for `Deref` targets so they match in both the main
     /// body and the sidebar.
-    pub(super) deref_id_map: FxHashMap<DefId, String>,
+    pub(super) deref_id_map: DefIdMap<String>,
     /// The map used to ensure all generated 'id=' attributes are unique.
     pub(super) id_map: IdMap,
     /// Shared mutable state.
@@ -544,7 +544,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
             dst,
             render_redirect_pages: false,
             id_map,
-            deref_id_map: FxHashMap::default(),
+            deref_id_map: Default::default(),
             shared: Rc::new(scx),
             include_sources,
             types_with_notable_traits: FxHashSet::default(),
@@ -572,7 +572,7 @@ impl<'tcx> FormatRenderer<'tcx> for Context<'tcx> {
             current: self.current.clone(),
             dst: self.dst.clone(),
             render_redirect_pages: self.render_redirect_pages,
-            deref_id_map: FxHashMap::default(),
+            deref_id_map: Default::default(),
             id_map: IdMap::new(),
             shared: Rc::clone(&self.shared),
             include_sources: self.include_sources,
diff --git a/src/librustdoc/html/render/mod.rs b/src/librustdoc/html/render/mod.rs
index f95d8e43035..d644293d3ef 100644
--- a/src/librustdoc/html/render/mod.rs
+++ b/src/librustdoc/html/render/mod.rs
@@ -50,7 +50,7 @@ use rustc_ast_pretty::pprust;
 use rustc_attr::{ConstStability, Deprecation, StabilityLevel};
 use rustc_data_structures::fx::{FxHashMap, FxHashSet};
 use rustc_hir::def::CtorKind;
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::{DefId, DefIdSet};
 use rustc_hir::Mutability;
 use rustc_middle::middle::stability;
 use rustc_middle::ty;
@@ -1115,7 +1115,7 @@ fn render_assoc_items(
     it: DefId,
     what: AssocItemRender<'_>,
 ) {
-    let mut derefs = FxHashSet::default();
+    let mut derefs = DefIdSet::default();
     derefs.insert(it);
     render_assoc_items_inner(w, cx, containing_item, it, what, &mut derefs)
 }
@@ -1126,7 +1126,7 @@ fn render_assoc_items_inner(
     containing_item: &clean::Item,
     it: DefId,
     what: AssocItemRender<'_>,
-    derefs: &mut FxHashSet<DefId>,
+    derefs: &mut DefIdSet,
 ) {
     info!("Documenting associated items of {:?}", containing_item.name);
     let shared = Rc::clone(&cx.shared);
@@ -1215,7 +1215,7 @@ fn render_deref_methods(
     impl_: &Impl,
     container_item: &clean::Item,
     deref_mut: bool,
-    derefs: &mut FxHashSet<DefId>,
+    derefs: &mut DefIdSet,
 ) {
     let cache = cx.cache();
     let deref_type = impl_.inner_impl().trait_.as_ref().unwrap();
@@ -2175,7 +2175,7 @@ fn sidebar_assoc_items(cx: &Context<'_>, out: &mut Buffer, it: &clean::Item) {
             if let Some(impl_) =
                 v.iter().find(|i| i.trait_did() == cx.tcx().lang_items().deref_trait())
             {
-                let mut derefs = FxHashSet::default();
+                let mut derefs = DefIdSet::default();
                 derefs.insert(did);
                 sidebar_deref_methods(cx, out, impl_, v, &mut derefs, &mut used_links);
             }
@@ -2195,7 +2195,7 @@ fn sidebar_deref_methods(
     out: &mut Buffer,
     impl_: &Impl,
     v: &[Impl],
-    derefs: &mut FxHashSet<DefId>,
+    derefs: &mut DefIdSet,
     used_links: &mut FxHashSet<String>,
 ) {
     let c = cx.cache();
@@ -2921,7 +2921,7 @@ fn render_call_locations(w: &mut Buffer, cx: &mut Context<'_>, item: &clean::Ite
         // Look for the example file in the source map if it exists, otherwise return a dummy span
         let file_span = (|| {
             let source_map = tcx.sess.source_map();
-            let crate_src = tcx.sess.local_crate_source_file.as_ref()?;
+            let crate_src = tcx.sess.local_crate_source_file()?;
             let abs_crate_src = crate_src.canonicalize().ok()?;
             let crate_root = abs_crate_src.parent()?.parent()?;
             let rel_path = path.strip_prefix(crate_root).ok()?;
diff --git a/src/librustdoc/html/render/print_item.rs b/src/librustdoc/html/render/print_item.rs
index b93db7e28b2..f824c9e3ad2 100644
--- a/src/librustdoc/html/render/print_item.rs
+++ b/src/librustdoc/html/render/print_item.rs
@@ -531,7 +531,7 @@ fn item_function(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, f: &cle
         f.decl.output.as_return().and_then(|output| notable_traits_button(output, cx));
 
     wrap_into_item_decl(w, |w| {
-        wrap_item(w, "fn", |w| {
+        wrap_item(w, |w| {
             render_attributes_in_pre(w, it, "");
             w.reserve(header_len);
             write!(
@@ -570,7 +570,7 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
 
     // Output the trait definition
     wrap_into_item_decl(w, |w| {
-        wrap_item(w, "trait", |w| {
+        wrap_item(w, |w| {
             render_attributes_in_pre(w, it, "");
             write!(
                 w,
@@ -1051,7 +1051,7 @@ fn item_trait(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean:
 
 fn item_trait_alias(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::TraitAlias) {
     wrap_into_item_decl(w, |w| {
-        wrap_item(w, "trait-alias", |w| {
+        wrap_item(w, |w| {
             render_attributes_in_pre(w, it, "");
             write!(
                 w,
@@ -1075,7 +1075,7 @@ fn item_trait_alias(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &
 
 fn item_opaque_ty(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::OpaqueTy) {
     wrap_into_item_decl(w, |w| {
-        wrap_item(w, "opaque", |w| {
+        wrap_item(w, |w| {
             render_attributes_in_pre(w, it, "");
             write!(
                 w,
@@ -1099,7 +1099,7 @@ fn item_opaque_ty(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &cl
 
 fn item_typedef(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clean::Typedef) {
     fn write_content(w: &mut Buffer, cx: &Context<'_>, it: &clean::Item, t: &clean::Typedef) {
-        wrap_item(w, "typedef", |w| {
+        wrap_item(w, |w| {
             render_attributes_in_pre(w, it, "");
             write!(w, "{}", visibility_print_with_space(it.visibility(cx.tcx()), it.item_id, cx));
             write!(
@@ -1128,7 +1128,7 @@ fn item_typedef(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, t: &clea
 
 fn item_union(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean::Union) {
     wrap_into_item_decl(w, |w| {
-        wrap_item(w, "union", |w| {
+        wrap_item(w, |w| {
             render_attributes_in_pre(w, it, "");
             render_union(w, it, Some(&s.generics), &s.fields, "", cx);
         });
@@ -1193,7 +1193,7 @@ fn item_enum(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, e: &clean::
     let tcx = cx.tcx();
     let count_variants = e.variants().count();
     wrap_into_item_decl(w, |w| {
-        wrap_item(w, "enum", |w| {
+        wrap_item(w, |w| {
             render_attributes_in_pre(w, it, "");
             write!(
                 w,
@@ -1357,17 +1357,17 @@ fn item_proc_macro(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, m: &c
         let name = it.name.expect("proc-macros always have names");
         match m.kind {
             MacroKind::Bang => {
-                wrap_item(w, "macro", |w| {
+                wrap_item(w, |w| {
                     write!(w, "{}!() {{ /* proc-macro */ }}", name);
                 });
             }
             MacroKind::Attr => {
-                wrap_item(w, "attr", |w| {
+                wrap_item(w, |w| {
                     write!(w, "#[{}]", name);
                 });
             }
             MacroKind::Derive => {
-                wrap_item(w, "derive", |w| {
+                wrap_item(w, |w| {
                     write!(w, "#[derive({})]", name);
                     if !m.helpers.is_empty() {
                         w.push_str("\n{\n");
@@ -1401,7 +1401,7 @@ fn item_primitive(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item) {
 
 fn item_constant(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, c: &clean::Constant) {
     wrap_into_item_decl(w, |w| {
-        wrap_item(w, "const", |w| {
+        wrap_item(w, |w| {
             let tcx = cx.tcx();
             render_attributes_in_code(w, it);
 
@@ -1451,7 +1451,7 @@ fn item_constant(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, c: &cle
 
 fn item_struct(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean::Struct) {
     wrap_into_item_decl(w, |w| {
-        wrap_item(w, "struct", |w| {
+        wrap_item(w, |w| {
             render_attributes_in_code(w, it);
             render_struct(w, it, Some(&s.generics), s.ctor_kind, &s.fields, "", true, cx);
         });
@@ -1504,7 +1504,7 @@ fn item_struct(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean
 
 fn item_static(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean::Static) {
     wrap_into_item_decl(w, |w| {
-        wrap_item(w, "static", |w| {
+        wrap_item(w, |w| {
             render_attributes_in_code(w, it);
             write!(
                 w,
@@ -1521,7 +1521,7 @@ fn item_static(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item, s: &clean
 
 fn item_foreign_type(w: &mut Buffer, cx: &mut Context<'_>, it: &clean::Item) {
     wrap_into_item_decl(w, |w| {
-        wrap_item(w, "foreigntype", |w| {
+        wrap_item(w, |w| {
             w.write_str("extern {\n");
             render_attributes_in_code(w, it);
             write!(
@@ -1618,11 +1618,11 @@ where
     w.write_str("</div>")
 }
 
-fn wrap_item<F>(w: &mut Buffer, item_name: &str, f: F)
+fn wrap_item<F>(w: &mut Buffer, f: F)
 where
     F: FnOnce(&mut Buffer),
 {
-    w.write_fmt(format_args!("<pre class=\"rust {}\"><code>", item_name));
+    w.write_str(r#"<pre class="rust"><code>"#);
     f(w);
     w.write_str("</code></pre>");
 }
diff --git a/src/librustdoc/html/render/search_index.rs b/src/librustdoc/html/render/search_index.rs
index c64349f413c..5b0caac099b 100644
--- a/src/librustdoc/html/render/search_index.rs
+++ b/src/librustdoc/html/render/search_index.rs
@@ -29,7 +29,7 @@ pub(crate) fn build_index<'tcx>(
     // Attach all orphan items to the type's definition if the type
     // has since been learned.
     for &OrphanImplItem { parent, ref item, ref impl_generics } in &cache.orphan_impl_items {
-        if let Some(&(ref fqp, _)) = cache.paths.get(&parent) {
+        if let Some((fqp, _)) = cache.paths.get(&parent) {
             let desc = item
                 .doc_value()
                 .map_or_else(String::new, |s| short_markdown_summary(&s, &item.link_names(cache)));
@@ -573,7 +573,7 @@ fn get_fn_inputs_and_outputs<'tcx>(
     let decl = &func.decl;
 
     let combined_generics;
-    let (self_, generics) = if let Some(&(ref impl_self, ref impl_generics)) = impl_generics {
+    let (self_, generics) = if let Some((impl_self, impl_generics)) = impl_generics {
         match (impl_generics.is_empty(), func.generics.is_empty()) {
             (true, _) => (Some(impl_self), &func.generics),
             (_, true) => (Some(impl_self), impl_generics),
diff --git a/src/librustdoc/html/render/write_shared.rs b/src/librustdoc/html/render/write_shared.rs
index ca3e9916487..bc8badad38e 100644
--- a/src/librustdoc/html/render/write_shared.rs
+++ b/src/librustdoc/html/render/write_shared.rs
@@ -138,7 +138,7 @@ pub(super) fn write_shared(
         Ok((ret, krates))
     }
 
-    /// Read a file and return all lines that match the <code>"{crate}":{data},\ </code> format,
+    /// Read a file and return all lines that match the <code>"{crate}":{data},\</code> format,
     /// and return a tuple `(Vec<DataString>, Vec<CrateNameString>)`.
     ///
     /// This forms the payload of files that look like this:
diff --git a/src/librustdoc/html/static/css/rustdoc.css b/src/librustdoc/html/static/css/rustdoc.css
index a08b8d89db6..e0d64c231a6 100644
--- a/src/librustdoc/html/static/css/rustdoc.css
+++ b/src/librustdoc/html/static/css/rustdoc.css
@@ -497,7 +497,7 @@ ul.block, .block li {
 	padding-left: 24px;
 }
 
-.sidebar a, .sidebar .current {
+.sidebar a {
 	color: var(--sidebar-link-color);
 }
 .sidebar .current,
@@ -1907,9 +1907,15 @@ in storage.js
 }
 .scraped-example:not(.expanded) .code-wrapper:before {
 	top: 0;
+	background: linear-gradient(to bottom,
+		var(--scrape-example-code-wrapper-background-start),
+		var(--scrape-example-code-wrapper-background-end));
 }
 .scraped-example:not(.expanded) .code-wrapper:after {
 	bottom: 0;
+	background: linear-gradient(to top,
+		var(--scrape-example-code-wrapper-background-start),
+		var(--scrape-example-code-wrapper-background-end));
 }
 
 .scraped-example .code-wrapper .example-wrap {
diff --git a/src/librustdoc/html/static/css/settings.css b/src/librustdoc/html/static/css/settings.css
index 91419093147..4e9803fe236 100644
--- a/src/librustdoc/html/static/css/settings.css
+++ b/src/librustdoc/html/static/css/settings.css
@@ -1,13 +1,8 @@
 .setting-line {
-	margin: 0.6em 0 0.6em 0.3em;
+	margin: 1.2em 0.6em;
 	position: relative;
 }
 
-.setting-line .choices {
-	display: flex;
-	flex-wrap: wrap;
-}
-
 .setting-line .radio-line input,
 .setting-line .settings-toggle input {
 	margin-right: 0.3em;
@@ -33,16 +28,12 @@
 	padding-bottom: 1px;
 }
 
-.radio-line .setting-name {
-	width: 100%;
-}
-
 .radio-line .choice {
 	margin-top: 0.1em;
 	margin-bottom: 0.1em;
 	min-width: 3.8em;
 	padding: 0.3em;
-	display: flex;
+	display: inline-flex;
 	align-items: center;
 	cursor: pointer;
 }
@@ -59,10 +50,6 @@
 	cursor: pointer;
 }
 
-#settings .setting-line {
-	margin: 1.2em 0.6em;
-}
-
 .setting-line .radio-line input:checked {
 	box-shadow: inset 0 0 0 3px var(--main-background-color);
 	background-color: var(--settings-input-color);
diff --git a/src/librustdoc/html/static/css/themes/ayu.css b/src/librustdoc/html/static/css/themes/ayu.css
index 979e7e0f999..ed779bf6166 100644
--- a/src/librustdoc/html/static/css/themes/ayu.css
+++ b/src/librustdoc/html/static/css/themes/ayu.css
@@ -97,6 +97,8 @@ Original by Dempfi (https://github.com/dempfi/ayu)
 	--scrape-example-help-color: #eee;
 	--scrape-example-help-hover-border-color: #fff;
 	--scrape-example-help-hover-color: #fff;
+	--scrape-example-code-wrapper-background-start: rgba(15, 20, 25, 1);
+	--scrape-example-code-wrapper-background-end: rgba(15, 20, 25, 0);
 }
 
 h1, h2, h3, h4 {
@@ -203,10 +205,3 @@ above the `@media (max-width: 700px)` rules due to a bug in the css checker */
 #source-sidebar div.files > a.selected {
 	color: #ffb44c;
 }
-
-.scraped-example:not(.expanded) .code-wrapper::before {
-	background: linear-gradient(to bottom, rgba(15, 20, 25, 1), rgba(15, 20, 25, 0));
-}
-.scraped-example:not(.expanded) .code-wrapper::after {
-	background: linear-gradient(to top, rgba(15, 20, 25, 1), rgba(15, 20, 25, 0));
-}
diff --git a/src/librustdoc/html/static/css/themes/dark.css b/src/librustdoc/html/static/css/themes/dark.css
index fb15863b027..3766f0daa42 100644
--- a/src/librustdoc/html/static/css/themes/dark.css
+++ b/src/librustdoc/html/static/css/themes/dark.css
@@ -92,6 +92,8 @@
 	--scrape-example-help-color: #eee;
 	--scrape-example-help-hover-border-color: #fff;
 	--scrape-example-help-hover-color: #fff;
+	--scrape-example-code-wrapper-background-start: rgba(53, 53, 53, 1);
+	--scrape-example-code-wrapper-background-end: rgba(53, 53, 53, 0);
 }
 
 #search-tabs > button:not(.selected) {
@@ -103,10 +105,3 @@
 	border-top-color: #0089ff;
 	background-color: #353535;
 }
-
-.scraped-example:not(.expanded) .code-wrapper::before {
-	background: linear-gradient(to bottom, rgba(53, 53, 53, 1), rgba(53, 53, 53, 0));
-}
-.scraped-example:not(.expanded) .code-wrapper::after {
-	background: linear-gradient(to top, rgba(53, 53, 53, 1), rgba(53, 53, 53, 0));
-}
diff --git a/src/librustdoc/html/static/css/themes/light.css b/src/librustdoc/html/static/css/themes/light.css
index 053fa78d1dc..8a7f6abcf8d 100644
--- a/src/librustdoc/html/static/css/themes/light.css
+++ b/src/librustdoc/html/static/css/themes/light.css
@@ -89,6 +89,8 @@
 	--scrape-example-help-color: #333;
 	--scrape-example-help-hover-border-color: #000;
 	--scrape-example-help-hover-color: #000;
+	--scrape-example-code-wrapper-background-start: rgba(255, 255, 255, 1);
+	--scrape-example-code-wrapper-background-end: rgba(255, 255, 255, 0);
 }
 
 #search-tabs > button:not(.selected) {
@@ -100,10 +102,3 @@
 	background-color: #ffffff;
 	border-top-color: #0089ff;
 }
-
-.scraped-example:not(.expanded) .code-wrapper::before {
-	background: linear-gradient(to bottom, rgba(255, 255, 255, 1), rgba(255, 255, 255, 0));
-}
-.scraped-example:not(.expanded) .code-wrapper::after {
-	background: linear-gradient(to top, rgba(255, 255, 255, 1), rgba(255, 255, 255, 0));
-}
diff --git a/src/librustdoc/html/static/js/main.js b/src/librustdoc/html/static/js/main.js
index f52229d8095..604ab147f6a 100644
--- a/src/librustdoc/html/static/js/main.js
+++ b/src/librustdoc/html/static/js/main.js
@@ -390,7 +390,8 @@ function loadCss(cssUrl) {
         }
 
         if (document.activeElement.tagName === "INPUT" &&
-            document.activeElement.type !== "checkbox") {
+            document.activeElement.type !== "checkbox" &&
+            document.activeElement.type !== "radio") {
             switch (getVirtualKey(ev)) {
             case "Escape":
                 handleEscape(ev);
@@ -803,15 +804,10 @@ function loadCss(cssUrl) {
         }
     });
 
-    function handleClick(id, f) {
-        const elem = document.getElementById(id);
-        if (elem) {
-            elem.addEventListener("click", f);
-        }
+    const mainElem = document.getElementById(MAIN_ID);
+    if (mainElem) {
+        mainElem.addEventListener("click", hideSidebar);
     }
-    handleClick(MAIN_ID, () => {
-        hideSidebar();
-    });
 
     onEachLazy(document.querySelectorAll("a[href^='#']"), el => {
         // For clicks on internal links (<A> tags with a hash property), we expand the section we're
@@ -945,7 +941,7 @@ function loadCss(cssUrl) {
                 return;
             }
             if (!this.NOTABLE_FORCE_VISIBLE &&
-                !elemIsInParent(event.relatedTarget, window.CURRENT_NOTABLE_ELEMENT)) {
+                !elemIsInParent(ev.relatedTarget, window.CURRENT_NOTABLE_ELEMENT)) {
                 hideNotable(true);
             }
         };
@@ -1087,6 +1083,9 @@ function loadCss(cssUrl) {
      * Show the help popup menu.
      */
     function showHelp() {
+        // Prevent `blur` events from being dispatched as a result of closing
+        // other modals.
+        getHelpButton().querySelector("a").focus();
         const menu = getHelpMenu(true);
         if (menu.style.display === "none") {
             window.hideAllModals();
diff --git a/src/librustdoc/html/static/js/search.js b/src/librustdoc/html/static/js/search.js
index 1b8822b0b2b..88592fa0c84 100644
--- a/src/librustdoc/html/static/js/search.js
+++ b/src/librustdoc/html/static/js/search.js
@@ -781,7 +781,29 @@ function initSearch(rawSearchIndex) {
                     return a - b;
                 }
 
-                // Sort by non levenshtein results and then levenshtein results by the distance
+                // sort by index of keyword in item name (no literal occurrence goes later)
+                a = (aaa.index < 0);
+                b = (bbb.index < 0);
+                if (a !== b) {
+                    return a - b;
+                }
+
+                // Sort by distance in the path part, if specified
+                // (less changes required to match means higher rankings)
+                a = aaa.path_lev;
+                b = bbb.path_lev;
+                if (a !== b) {
+                    return a - b;
+                }
+
+                // (later literal occurrence, if any, goes later)
+                a = aaa.index;
+                b = bbb.index;
+                if (a !== b) {
+                    return a - b;
+                }
+
+                // Sort by distance in the name part, the last part of the path
                 // (less changes required to match means higher rankings)
                 a = (aaa.lev);
                 b = (bbb.lev);
@@ -810,19 +832,6 @@ function initSearch(rawSearchIndex) {
                     return (a > b ? +1 : -1);
                 }
 
-                // sort by index of keyword in item name (no literal occurrence goes later)
-                a = (aaa.index < 0);
-                b = (bbb.index < 0);
-                if (a !== b) {
-                    return a - b;
-                }
-                // (later literal occurrence, if any, goes later)
-                a = aaa.index;
-                b = bbb.index;
-                if (a !== b) {
-                    return a - b;
-                }
-
                 // special precedence for primitive and keyword pages
                 if ((aaa.item.ty === TY_PRIMITIVE && bbb.item.ty !== TY_KEYWORD) ||
                     (aaa.item.ty === TY_KEYWORD && bbb.item.ty !== TY_PRIMITIVE)) {
@@ -1230,15 +1239,19 @@ function initSearch(rawSearchIndex) {
          * * `id` is the index in both `searchWords` and `searchIndex` arrays for this element.
          * * `index` is an `integer`` used to sort by the position of the word in the item's name.
          * * `lev` is the main metric used to sort the search results.
+         * * `path_lev` is zero if a single-component search query is used, otherwise it's the
+         *   distance computed for everything other than the last path component.
          *
          * @param {Results} results
          * @param {string} fullId
          * @param {integer} id
          * @param {integer} index
          * @param {integer} lev
+         * @param {integer} path_lev
          */
-        function addIntoResults(results, fullId, id, index, lev) {
-            if (lev === 0 || (!parsedQuery.literalSearch && lev <= MAX_LEV_DISTANCE)) {
+        function addIntoResults(results, fullId, id, index, lev, path_lev) {
+            const inBounds = lev <= MAX_LEV_DISTANCE || index !== -1;
+            if (lev === 0 || (!parsedQuery.literalSearch && inBounds)) {
                 if (results[fullId] !== undefined) {
                     const result = results[fullId];
                     if (result.dontValidate || result.lev <= lev) {
@@ -1250,6 +1263,7 @@ function initSearch(rawSearchIndex) {
                     index: index,
                     dontValidate: parsedQuery.literalSearch,
                     lev: lev,
+                    path_lev: path_lev,
                 };
             }
         }
@@ -1280,68 +1294,68 @@ function initSearch(rawSearchIndex) {
             if (!row || (filterCrates !== null && row.crate !== filterCrates)) {
                 return;
             }
-            let lev, lev_add = 0, index = -1;
+            let lev, index = -1, path_lev = 0;
             const fullId = row.id;
+            const searchWord = searchWords[pos];
 
             const in_args = findArg(row, elem, parsedQuery.typeFilter);
             const returned = checkReturned(row, elem, parsedQuery.typeFilter);
 
-            addIntoResults(results_in_args, fullId, pos, index, in_args);
-            addIntoResults(results_returned, fullId, pos, index, returned);
+            // path_lev is 0 because no parent path information is currently stored
+            // in the search index
+            addIntoResults(results_in_args, fullId, pos, -1, in_args, 0);
+            addIntoResults(results_returned, fullId, pos, -1, returned, 0);
 
             if (!typePassesFilter(parsedQuery.typeFilter, row.ty)) {
                 return;
             }
-            const searchWord = searchWords[pos];
 
-            if (parsedQuery.literalSearch) {
-                if (searchWord === elem.name) {
-                    addIntoResults(results_others, fullId, pos, -1, 0);
-                }
-                return;
+            const row_index = row.normalizedName.indexOf(elem.pathLast);
+            const word_index = searchWord.indexOf(elem.pathLast);
+
+            // lower indexes are "better" matches
+            // rank based on the "best" match
+            if (row_index === -1) {
+                index = word_index;
+            } else if (word_index === -1) {
+                index = row_index;
+            } else if (word_index < row_index) {
+                index = word_index;
+            } else {
+                index = row_index;
             }
 
             // No need to check anything else if it's a "pure" generics search.
             if (elem.name.length === 0) {
                 if (row.type !== null) {
                     lev = checkGenerics(row.type, elem, MAX_LEV_DISTANCE + 1);
-                    addIntoResults(results_others, fullId, pos, index, lev);
+                    // path_lev is 0 because we know it's empty
+                    addIntoResults(results_others, fullId, pos, index, lev, 0);
                 }
                 return;
             }
 
             if (elem.fullPath.length > 1) {
-                lev = checkPath(elem.pathWithoutLast, row);
-                if (lev > MAX_LEV_DISTANCE || (parsedQuery.literalSearch && lev !== 0)) {
+                path_lev = checkPath(elem.pathWithoutLast, row);
+                if (path_lev > MAX_LEV_DISTANCE) {
                     return;
-                } else if (lev > 0) {
-                    lev_add = lev / 10;
                 }
             }
 
-            if (searchWord.indexOf(elem.pathLast) > -1 ||
-                row.normalizedName.indexOf(elem.pathLast) > -1
-            ) {
-                index = row.normalizedName.indexOf(elem.pathLast);
-            }
-            lev = levenshtein(searchWord, elem.pathLast);
-            if (lev > 0 && elem.pathLast.length > 2 && searchWord.indexOf(elem.pathLast) > -1) {
-                if (elem.pathLast.length < 6) {
-                    lev = 1;
-                } else {
-                    lev = 0;
+            if (parsedQuery.literalSearch) {
+                if (searchWord === elem.name) {
+                    addIntoResults(results_others, fullId, pos, index, 0, path_lev);
                 }
-            }
-            lev += lev_add;
-            if (lev > MAX_LEV_DISTANCE) {
                 return;
-            } else if (index !== -1 && elem.fullPath.length < 2) {
-                lev -= 1;
             }
-            if (lev < 0) {
-                lev = 0;
+
+            lev = levenshtein(searchWord, elem.pathLast);
+
+            if (index === -1 && lev + path_lev > MAX_LEV_DISTANCE) {
+                return;
             }
-            addIntoResults(results_others, fullId, pos, index, lev);
+
+            addIntoResults(results_others, fullId, pos, index, lev, path_lev);
         }
 
         /**
@@ -1386,7 +1400,7 @@ function initSearch(rawSearchIndex) {
                 return;
             }
             const lev = Math.round(totalLev / nbLev);
-            addIntoResults(results, row.id, pos, 0, lev);
+            addIntoResults(results, row.id, pos, 0, lev, 0);
         }
 
         function innerRunQuery() {
diff --git a/src/librustdoc/html/static/js/settings.js b/src/librustdoc/html/static/js/settings.js
index 9ed8f63610f..84df1b7d391 100644
--- a/src/librustdoc/html/static/js/settings.js
+++ b/src/librustdoc/html/static/js/settings.js
@@ -135,7 +135,7 @@
                 // This is a select setting.
                 output += `\
 <div class="radio-line" id="${js_data_name}">
-    <span class="setting-name">${setting_name}</span>
+    <div class="setting-name">${setting_name}</div>
 <div class="choices">`;
                 onEach(setting["options"], option => {
                     const checked = option === setting["default"] ? " checked" : "";
diff --git a/src/librustdoc/json/import_finder.rs b/src/librustdoc/json/import_finder.rs
index c5c687df74f..982370aa21c 100644
--- a/src/librustdoc/json/import_finder.rs
+++ b/src/librustdoc/json/import_finder.rs
@@ -1,5 +1,4 @@
-use rustc_data_structures::fx::FxHashSet;
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::DefIdSet;
 
 use crate::{
     clean::{self, Import, ImportSource, Item},
@@ -14,14 +13,15 @@ use crate::{
 /// See [#100973](https://github.com/rust-lang/rust/issues/100973) and
 /// [#101103](https://github.com/rust-lang/rust/issues/101103) for times when
 /// this information is needed.
-pub(crate) fn get_imports(krate: clean::Crate) -> (clean::Crate, FxHashSet<DefId>) {
-    let mut finder = ImportFinder { imported: FxHashSet::default() };
+pub(crate) fn get_imports(krate: clean::Crate) -> (clean::Crate, DefIdSet) {
+    let mut finder = ImportFinder::default();
     let krate = finder.fold_crate(krate);
     (krate, finder.imported)
 }
 
+#[derive(Default)]
 struct ImportFinder {
-    imported: FxHashSet<DefId>,
+    imported: DefIdSet,
 }
 
 impl DocFolder for ImportFinder {
diff --git a/src/librustdoc/json/mod.rs b/src/librustdoc/json/mod.rs
index 1196f944faa..5adc0d2a40e 100644
--- a/src/librustdoc/json/mod.rs
+++ b/src/librustdoc/json/mod.rs
@@ -13,8 +13,8 @@ use std::io::{BufWriter, Write};
 use std::path::PathBuf;
 use std::rc::Rc;
 
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_hir::def_id::DefId;
+use rustc_data_structures::fx::FxHashMap;
+use rustc_hir::def_id::{DefId, DefIdSet};
 use rustc_middle::ty::TyCtxt;
 use rustc_session::Session;
 use rustc_span::def_id::LOCAL_CRATE;
@@ -40,7 +40,7 @@ pub(crate) struct JsonRenderer<'tcx> {
     /// The directory where the blob will be written to.
     out_path: PathBuf,
     cache: Rc<Cache>,
-    imported_items: FxHashSet<DefId>,
+    imported_items: DefIdSet,
 }
 
 impl<'tcx> JsonRenderer<'tcx> {
diff --git a/src/librustdoc/passes/collect_trait_impls.rs b/src/librustdoc/passes/collect_trait_impls.rs
index 79db3c6c3e7..7d15a207d06 100644
--- a/src/librustdoc/passes/collect_trait_impls.rs
+++ b/src/librustdoc/passes/collect_trait_impls.rs
@@ -7,8 +7,8 @@ use crate::core::DocContext;
 use crate::formats::cache::Cache;
 use crate::visit::DocVisitor;
 
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
-use rustc_hir::def_id::{DefId, LOCAL_CRATE};
+use rustc_data_structures::fx::FxHashSet;
+use rustc_hir::def_id::{DefId, DefIdMap, DefIdSet, LOCAL_CRATE};
 use rustc_middle::ty::{self, DefIdTree};
 use rustc_span::symbol::sym;
 
@@ -126,14 +126,14 @@ pub(crate) fn collect_trait_impls(mut krate: Crate, cx: &mut DocContext<'_>) ->
     });
 
     let mut cleaner = BadImplStripper { prims, items: crate_items, cache: &cx.cache };
-    let mut type_did_to_deref_target: FxHashMap<DefId, &Type> = FxHashMap::default();
+    let mut type_did_to_deref_target: DefIdMap<&Type> = DefIdMap::default();
 
     // Follow all `Deref` targets of included items and recursively add them as valid
     fn add_deref_target(
         cx: &DocContext<'_>,
-        map: &FxHashMap<DefId, &Type>,
+        map: &DefIdMap<&Type>,
         cleaner: &mut BadImplStripper<'_>,
-        targets: &mut FxHashSet<DefId>,
+        targets: &mut DefIdSet,
         type_did: DefId,
     ) {
         if let Some(target) = map.get(&type_did) {
@@ -177,7 +177,7 @@ pub(crate) fn collect_trait_impls(mut krate: Crate, cx: &mut DocContext<'_>) ->
                         // `Deref` target type and the impl for type positions, this map of types is keyed by
                         // `DefId` and for convenience uses a special cleaner that accepts `DefId`s directly.
                         if cleaner.keep_impl_with_def_id(for_did.into()) {
-                            let mut targets = FxHashSet::default();
+                            let mut targets = DefIdSet::default();
                             targets.insert(for_did);
                             add_deref_target(
                                 cx,
diff --git a/src/librustdoc/visit_ast.rs b/src/librustdoc/visit_ast.rs
index 7db47035967..00ea6ca4152 100644
--- a/src/librustdoc/visit_ast.rs
+++ b/src/librustdoc/visit_ast.rs
@@ -1,14 +1,11 @@
 //! The Rust AST Visitor. Extracts useful information and massages it into a form
 //! usable for `clean`.
 
-use rustc_data_structures::fx::{FxHashMap, FxHashSet};
+use rustc_data_structures::fx::FxHashSet;
 use rustc_hir as hir;
 use rustc_hir::def::{DefKind, Res};
-use rustc_hir::def_id::DefId;
-use rustc_hir::intravisit::{walk_item, Visitor};
-use rustc_hir::Node;
-use rustc_hir::CRATE_HIR_ID;
-use rustc_middle::hir::nested_filter;
+use rustc_hir::def_id::{DefId, DefIdMap};
+use rustc_hir::{HirIdSet, Node, CRATE_HIR_ID};
 use rustc_middle::ty::TyCtxt;
 use rustc_span::def_id::{CRATE_DEF_ID, LOCAL_CRATE};
 use rustc_span::symbol::{kw, sym, Symbol};
@@ -59,34 +56,29 @@ pub(crate) fn inherits_doc_hidden(tcx: TyCtxt<'_>, mut node: hir::HirId) -> bool
     false
 }
 
+// Also, is there some reason that this doesn't use the 'visit'
+// framework from syntax?.
+
 pub(crate) struct RustdocVisitor<'a, 'tcx> {
     cx: &'a mut core::DocContext<'tcx>,
-    view_item_stack: FxHashSet<hir::HirId>,
+    view_item_stack: HirIdSet,
     inlining: bool,
     /// Are the current module and all of its parents public?
     inside_public_path: bool,
-    exact_paths: FxHashMap<DefId, Vec<Symbol>>,
-    modules: Vec<Module<'tcx>>,
+    exact_paths: DefIdMap<Vec<Symbol>>,
 }
 
 impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
     pub(crate) fn new(cx: &'a mut core::DocContext<'tcx>) -> RustdocVisitor<'a, 'tcx> {
         // If the root is re-exported, terminate all recursion.
-        let mut stack = FxHashSet::default();
+        let mut stack = HirIdSet::default();
         stack.insert(hir::CRATE_HIR_ID);
-        let om = Module::new(
-            cx.tcx.crate_name(LOCAL_CRATE),
-            hir::CRATE_HIR_ID,
-            cx.tcx.hir().root_module().spans.inner_span,
-        );
-
         RustdocVisitor {
             cx,
             view_item_stack: stack,
             inlining: false,
             inside_public_path: true,
-            exact_paths: FxHashMap::default(),
-            modules: vec![om],
+            exact_paths: Default::default(),
         }
     }
 
@@ -96,10 +88,12 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
     }
 
     pub(crate) fn visit(mut self) -> Module<'tcx> {
-        let root_module = self.cx.tcx.hir().root_module();
-        self.visit_mod_contents(CRATE_HIR_ID, root_module);
-
-        let mut top_level_module = self.modules.pop().unwrap();
+        let mut top_level_module = self.visit_mod_contents(
+            hir::CRATE_HIR_ID,
+            self.cx.tcx.hir().root_module(),
+            self.cx.tcx.crate_name(LOCAL_CRATE),
+            None,
+        );
 
         // `#[macro_export] macro_rules!` items are reexported at the top level of the
         // crate, regardless of where they're defined. We want to document the
@@ -114,13 +108,15 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         // macro in the same module.
         let mut inserted = FxHashSet::default();
         for export in self.cx.tcx.module_reexports(CRATE_DEF_ID).unwrap_or(&[]) {
-            if let Res::Def(DefKind::Macro(_), def_id) = export.res &&
-                let Some(local_def_id) = def_id.as_local() &&
-                self.cx.tcx.has_attr(def_id, sym::macro_export) &&
-                inserted.insert(def_id)
-            {
-                    let item = self.cx.tcx.hir().expect_item(local_def_id);
-                    top_level_module.items.push((item, None, None));
+            if let Res::Def(DefKind::Macro(_), def_id) = export.res {
+                if let Some(local_def_id) = def_id.as_local() {
+                    if self.cx.tcx.has_attr(def_id, sym::macro_export) {
+                        if inserted.insert(def_id) {
+                            let item = self.cx.tcx.hir().expect_item(local_def_id);
+                            top_level_module.items.push((item, None, None));
+                        }
+                    }
+                }
             }
         }
 
@@ -154,23 +150,24 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         top_level_module
     }
 
-    /// This method will go through the given module items in two passes:
-    /// 1. The items which are not glob imports/reexports.
-    /// 2. The glob imports/reexports.
-    fn visit_mod_contents(&mut self, id: hir::HirId, m: &'tcx hir::Mod<'tcx>) {
-        debug!("Going through module {:?}", m);
+    fn visit_mod_contents(
+        &mut self,
+        id: hir::HirId,
+        m: &'tcx hir::Mod<'tcx>,
+        name: Symbol,
+        parent_id: Option<hir::HirId>,
+    ) -> Module<'tcx> {
+        let mut om = Module::new(name, id, m.spans.inner_span);
         let def_id = self.cx.tcx.hir().local_def_id(id).to_def_id();
         // Keep track of if there were any private modules in the path.
         let orig_inside_public_path = self.inside_public_path;
         self.inside_public_path &= self.cx.tcx.visibility(def_id).is_public();
-
-        // Reimplementation of `walk_mod` because we need to do it in two passes (explanations in
-        // the second loop):
         for &i in m.item_ids {
             let item = self.cx.tcx.hir().item(i);
-            if !matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
-                self.visit_item(item);
+            if matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
+                continue;
             }
+            self.visit_item(item, None, &mut om, parent_id);
         }
         for &i in m.item_ids {
             let item = self.cx.tcx.hir().item(i);
@@ -178,10 +175,11 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
             // Later passes in rustdoc will de-duplicate by name and kind, so if glob-
             // imported items appear last, then they'll be the ones that get discarded.
             if matches!(item.kind, hir::ItemKind::Use(_, hir::UseKind::Glob)) {
-                self.visit_item(item);
+                self.visit_item(item, None, &mut om, parent_id);
             }
         }
         self.inside_public_path = orig_inside_public_path;
+        om
     }
 
     /// Tries to resolve the target of a `pub use` statement and inlines the
@@ -199,6 +197,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         res: Res,
         renamed: Option<Symbol>,
         glob: bool,
+        om: &mut Module<'tcx>,
         please_inline: bool,
     ) -> bool {
         debug!("maybe_inline_local res: {:?}", res);
@@ -249,20 +248,20 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                 let prev = mem::replace(&mut self.inlining, true);
                 for &i in m.item_ids {
                     let i = self.cx.tcx.hir().item(i);
-                    self.visit_item_inner(i, None, Some(id));
+                    self.visit_item(i, None, om, Some(id));
                 }
                 self.inlining = prev;
                 true
             }
             Node::Item(it) if !glob => {
                 let prev = mem::replace(&mut self.inlining, true);
-                self.visit_item_inner(it, renamed, Some(id));
+                self.visit_item(it, renamed, om, Some(id));
                 self.inlining = prev;
                 true
             }
             Node::ForeignItem(it) if !glob => {
                 let prev = mem::replace(&mut self.inlining, true);
-                self.visit_foreign_item_inner(it, renamed);
+                self.visit_foreign_item(it, renamed, om);
                 self.inlining = prev;
                 true
             }
@@ -272,22 +271,13 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
         ret
     }
 
-    #[inline]
-    fn add_to_current_mod(
+    fn visit_item(
         &mut self,
         item: &'tcx hir::Item<'_>,
         renamed: Option<Symbol>,
+        om: &mut Module<'tcx>,
         parent_id: Option<hir::HirId>,
     ) {
-        self.modules.last_mut().unwrap().items.push((item, renamed, parent_id))
-    }
-
-    fn visit_item_inner(
-        &mut self,
-        item: &'tcx hir::Item<'_>,
-        renamed: Option<Symbol>,
-        parent_id: Option<hir::HirId>,
-    ) -> bool {
         debug!("visiting item {:?}", item);
         let name = renamed.unwrap_or(item.ident.name);
 
@@ -302,7 +292,7 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
             hir::ItemKind::ForeignMod { items, .. } => {
                 for item in items {
                     let item = self.cx.tcx.hir().foreign_item(item.id);
-                    self.visit_foreign_item_inner(item, None);
+                    self.visit_foreign_item(item, None, om);
                 }
             }
             // If we're inlining, skip private items or item reexported as "_".
@@ -335,13 +325,14 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                             res,
                             ident,
                             is_glob,
+                            om,
                             please_inline,
                         ) {
                             continue;
                         }
                     }
 
-                    self.add_to_current_mod(item, renamed, parent_id);
+                    om.items.push((item, renamed, parent_id))
                 }
             }
             hir::ItemKind::Macro(ref macro_def, _) => {
@@ -361,11 +352,11 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
                 let nonexported = !self.cx.tcx.has_attr(def_id, sym::macro_export);
 
                 if is_macro_2_0 || nonexported || self.inlining {
-                    self.add_to_current_mod(item, renamed, None);
+                    om.items.push((item, renamed, None));
                 }
             }
             hir::ItemKind::Mod(ref m) => {
-                self.enter_mod(item.hir_id(), m, name);
+                om.mods.push(self.visit_mod_contents(item.hir_id(), m, name, parent_id));
             }
             hir::ItemKind::Fn(..)
             | hir::ItemKind::ExternCrate(..)
@@ -376,92 +367,33 @@ impl<'a, 'tcx> RustdocVisitor<'a, 'tcx> {
             | hir::ItemKind::OpaqueTy(..)
             | hir::ItemKind::Static(..)
             | hir::ItemKind::Trait(..)
-            | hir::ItemKind::TraitAlias(..) => {
-                self.add_to_current_mod(item, renamed, parent_id);
-            }
+            | hir::ItemKind::TraitAlias(..) => om.items.push((item, renamed, parent_id)),
             hir::ItemKind::Const(..) => {
                 // Underscore constants do not correspond to a nameable item and
                 // so are never useful in documentation.
                 if name != kw::Underscore {
-                    self.add_to_current_mod(item, renamed, parent_id);
+                    om.items.push((item, renamed, parent_id));
                 }
             }
             hir::ItemKind::Impl(impl_) => {
                 // Don't duplicate impls when inlining or if it's implementing a trait, we'll pick
                 // them up regardless of where they're located.
                 if !self.inlining && impl_.of_trait.is_none() {
-                    self.add_to_current_mod(item, None, None);
+                    om.items.push((item, None, None));
                 }
             }
         }
-        true
     }
 
-    fn visit_foreign_item_inner(
+    fn visit_foreign_item(
         &mut self,
         item: &'tcx hir::ForeignItem<'_>,
         renamed: Option<Symbol>,
+        om: &mut Module<'tcx>,
     ) {
         // If inlining we only want to include public functions.
         if !self.inlining || self.cx.tcx.visibility(item.owner_id).is_public() {
-            self.modules.last_mut().unwrap().foreigns.push((item, renamed));
+            om.foreigns.push((item, renamed));
         }
     }
-
-    /// This method will create a new module and push it onto the "modules stack" then call
-    /// `visit_mod_contents`. Once done, it'll remove it from the "modules stack" and instead
-    /// add into the list of modules of the current module.
-    fn enter_mod(&mut self, id: hir::HirId, m: &'tcx hir::Mod<'tcx>, name: Symbol) {
-        self.modules.push(Module::new(name, id, m.spans.inner_span));
-
-        self.visit_mod_contents(id, m);
-
-        let last = self.modules.pop().unwrap();
-        self.modules.last_mut().unwrap().mods.push(last);
-    }
-}
-
-// We need to implement this visitor so it'll go everywhere and retrieve items we're interested in
-// such as impl blocks in const blocks.
-impl<'a, 'tcx> Visitor<'tcx> for RustdocVisitor<'a, 'tcx> {
-    type NestedFilter = nested_filter::All;
-
-    fn nested_visit_map(&mut self) -> Self::Map {
-        self.cx.tcx.hir()
-    }
-
-    fn visit_item(&mut self, i: &'tcx hir::Item<'tcx>) {
-        let parent_id = if self.modules.len() > 1 {
-            Some(self.modules[self.modules.len() - 2].id)
-        } else {
-            None
-        };
-        if self.visit_item_inner(i, None, parent_id) {
-            walk_item(self, i);
-        }
-    }
-
-    fn visit_mod(&mut self, _: &hir::Mod<'tcx>, _: Span, _: hir::HirId) {
-        // Handled in `visit_item_inner`
-    }
-
-    fn visit_use(&mut self, _: &hir::UsePath<'tcx>, _: hir::HirId) {
-        // Handled in `visit_item_inner`
-    }
-
-    fn visit_path(&mut self, _: &hir::Path<'tcx>, _: hir::HirId) {
-        // Handled in `visit_item_inner`
-    }
-
-    fn visit_label(&mut self, _: &rustc_ast::Label) {
-        // Unneeded.
-    }
-
-    fn visit_infer(&mut self, _: &hir::InferArg) {
-        // Unneeded.
-    }
-
-    fn visit_lifetime(&mut self, _: &hir::Lifetime) {
-        // Unneeded.
-    }
 }
diff --git a/src/librustdoc/visit_lib.rs b/src/librustdoc/visit_lib.rs
index e490559b0e9..fd4f9254107 100644
--- a/src/librustdoc/visit_lib.rs
+++ b/src/librustdoc/visit_lib.rs
@@ -1,14 +1,13 @@
 use crate::core::DocContext;
-use rustc_data_structures::fx::FxHashSet;
 use rustc_hir::def::DefKind;
-use rustc_hir::def_id::DefId;
+use rustc_hir::def_id::{DefId, DefIdSet};
 use rustc_middle::ty::TyCtxt;
 
 // FIXME: this may not be exhaustive, but is sufficient for rustdocs current uses
 
 #[derive(Default)]
 pub(crate) struct RustdocEffectiveVisibilities {
-    extern_public: FxHashSet<DefId>,
+    extern_public: DefIdSet,
 }
 
 macro_rules! define_method {
@@ -43,9 +42,9 @@ pub(crate) fn lib_embargo_visit_item(cx: &mut DocContext<'_>, def_id: DefId) {
 struct LibEmbargoVisitor<'a, 'tcx> {
     tcx: TyCtxt<'tcx>,
     // Effective visibilities for reachable nodes
-    extern_public: &'a mut FxHashSet<DefId>,
+    extern_public: &'a mut DefIdSet,
     // Keeps track of already visited modules, in case a module re-exports its parent
-    visited_mods: FxHashSet<DefId>,
+    visited_mods: DefIdSet,
 }
 
 impl LibEmbargoVisitor<'_, '_> {
diff --git a/src/llvm-project b/src/llvm-project
-Subproject 9ad24035fea8d309753f5e39e6eb53d1d0eb39c
+Subproject 477e7285b12f876ad105188cfcfc8adda7dc29a
diff --git a/src/tools/cargo b/src/tools/cargo
-Subproject 1cd6d3803dfb0b342272862a8590f5dfc9f7257
+Subproject 985d561f0bb9b76ec043a2b12511790ec7a2b95
diff --git a/src/tools/clippy/clippy_lints/src/inherent_impl.rs b/src/tools/clippy/clippy_lints/src/inherent_impl.rs
index c5abcc46254..e9b2e31a769 100644
--- a/src/tools/clippy/clippy_lints/src/inherent_impl.rs
+++ b/src/tools/clippy/clippy_lints/src/inherent_impl.rs
@@ -52,21 +52,19 @@ impl<'tcx> LateLintPass<'tcx> for MultipleInherentImpl {
         // List of spans to lint. (lint_span, first_span)
         let mut lint_spans = Vec::new();
 
-        for (_, impl_ids) in cx
+        let inherent_impls = cx
             .tcx
-            .crate_inherent_impls(())
-            .inherent_impls
-            .iter()
-            .filter(|(&id, impls)| {
-                impls.len() > 1
-                    // Check for `#[allow]` on the type definition
-                    && !is_lint_allowed(
-                        cx,
-                        MULTIPLE_INHERENT_IMPL,
-                        cx.tcx.hir().local_def_id_to_hir_id(id),
-                    )
-            })
-        {
+            .with_stable_hashing_context(|hcx| cx.tcx.crate_inherent_impls(()).inherent_impls.to_sorted(&hcx, true));
+
+        for (_, impl_ids) in inherent_impls.into_iter().filter(|(&id, impls)| {
+            impls.len() > 1
+            // Check for `#[allow]` on the type definition
+            && !is_lint_allowed(
+                cx,
+                MULTIPLE_INHERENT_IMPL,
+                cx.tcx.hir().local_def_id_to_hir_id(id),
+            )
+        }) {
             for impl_id in impl_ids.iter().map(|id| id.expect_local()) {
                 match type_map.entry(cx.tcx.type_of(impl_id)) {
                     Entry::Vacant(e) => {
diff --git a/src/tools/clippy/clippy_lints/src/instant_subtraction.rs b/src/tools/clippy/clippy_lints/src/instant_subtraction.rs
index dd1b23e7d9d..9f6e8940571 100644
--- a/src/tools/clippy/clippy_lints/src/instant_subtraction.rs
+++ b/src/tools/clippy/clippy_lints/src/instant_subtraction.rs
@@ -61,7 +61,7 @@ declare_clippy_lint! {
     /// [`Instant::now()`]: std::time::Instant::now;
     #[clippy::version = "1.65.0"]
     pub UNCHECKED_DURATION_SUBTRACTION,
-    suspicious,
+    pedantic,
     "finds unchecked subtraction of a 'Duration' from an 'Instant'"
 }
 
diff --git a/src/tools/clippy/clippy_lints/src/len_zero.rs b/src/tools/clippy/clippy_lints/src/len_zero.rs
index 9eba4675629..3c70c9cf19a 100644
--- a/src/tools/clippy/clippy_lints/src/len_zero.rs
+++ b/src/tools/clippy/clippy_lints/src/len_zero.rs
@@ -219,7 +219,7 @@ fn check_trait_items(cx: &LateContext<'_>, visited_trait: &Item<'_>, trait_items
         let is_empty = sym!(is_empty);
 
         let is_empty_method_found = current_and_super_traits
-            .iter()
+            .items()
             .flat_map(|&i| cx.tcx.associated_items(i).filter_by_name_unhygienic(is_empty))
             .any(|i| {
                 i.kind == ty::AssocKind::Fn
diff --git a/src/tools/clippy/clippy_lints/src/loops/while_immutable_condition.rs b/src/tools/clippy/clippy_lints/src/loops/while_immutable_condition.rs
index a63422d2a36..d1a1f773f87 100644
--- a/src/tools/clippy/clippy_lints/src/loops/while_immutable_condition.rs
+++ b/src/tools/clippy/clippy_lints/src/loops/while_immutable_condition.rs
@@ -35,7 +35,7 @@ pub(super) fn check<'tcx>(cx: &LateContext<'tcx>, cond: &'tcx Expr<'_>, expr: &'
         } else {
             return;
         };
-    let mutable_static_in_cond = var_visitor.def_ids.iter().any(|(_, v)| *v);
+    let mutable_static_in_cond = var_visitor.def_ids.items().any(|(_, v)| *v);
 
     let mut has_break_or_return_visitor = HasBreakOrReturnVisitor {
         has_break_or_return: false,
diff --git a/src/tools/clippy/clippy_lints/src/missing_trait_methods.rs b/src/tools/clippy/clippy_lints/src/missing_trait_methods.rs
index 68af8a672f6..3371b4cce32 100644
--- a/src/tools/clippy/clippy_lints/src/missing_trait_methods.rs
+++ b/src/tools/clippy/clippy_lints/src/missing_trait_methods.rs
@@ -80,19 +80,21 @@ impl<'tcx> LateLintPass<'tcx> for MissingTraitMethods {
                 }
             }
 
-            for assoc in provided.values() {
-                let source_map = cx.tcx.sess.source_map();
-                let definition_span = source_map.guess_head_span(cx.tcx.def_span(assoc.def_id));
+            cx.tcx.with_stable_hashing_context(|hcx| {
+                for assoc in provided.values_sorted(&hcx, true) {
+                    let source_map = cx.tcx.sess.source_map();
+                    let definition_span = source_map.guess_head_span(cx.tcx.def_span(assoc.def_id));
 
-                span_lint_and_help(
-                    cx,
-                    MISSING_TRAIT_METHODS,
-                    source_map.guess_head_span(item.span),
-                    &format!("missing trait method provided by default: `{}`", assoc.name),
-                    Some(definition_span),
-                    "implement the method",
-                );
-            }
+                    span_lint_and_help(
+                        cx,
+                        MISSING_TRAIT_METHODS,
+                        source_map.guess_head_span(item.span),
+                        &format!("missing trait method provided by default: `{}`", assoc.name),
+                        Some(definition_span),
+                        "implement the method",
+                    );
+                }
+            })
         }
     }
 }
diff --git a/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs b/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
index 1249db5dc47..8c9d4c5cfe6 100644
--- a/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
+++ b/src/tools/clippy/clippy_lints/src/needless_pass_by_value.rs
@@ -24,7 +24,7 @@ use rustc_span::symbol::kw;
 use rustc_span::{sym, Span};
 use rustc_target::spec::abi::Abi;
 use rustc_trait_selection::traits;
-use rustc_trait_selection::traits::misc::can_type_implement_copy;
+use rustc_trait_selection::traits::misc::type_allowed_to_implement_copy;
 use std::borrow::Cow;
 
 declare_clippy_lint! {
@@ -200,7 +200,7 @@ impl<'tcx> LateLintPass<'tcx> for NeedlessPassByValue {
                     let sugg = |diag: &mut Diagnostic| {
                         if let ty::Adt(def, ..) = ty.kind() {
                             if let Some(span) = cx.tcx.hir().span_if_local(def.did()) {
-                                if can_type_implement_copy(
+                                if type_allowed_to_implement_copy(
                                     cx.tcx,
                                     cx.param_env,
                                     ty,
diff --git a/src/tools/clippy/clippy_lints/src/pass_by_ref_or_value.rs b/src/tools/clippy/clippy_lints/src/pass_by_ref_or_value.rs
index 870a1c7d88d..2d21aaa4f7f 100644
--- a/src/tools/clippy/clippy_lints/src/pass_by_ref_or_value.rs
+++ b/src/tools/clippy/clippy_lints/src/pass_by_ref_or_value.rs
@@ -190,10 +190,10 @@ impl<'tcx> PassByRefOrValue {
                             // Don't lint if an unsafe pointer is created.
                             // TODO: Limit the check only to unsafe pointers to the argument (or part of the argument)
                             //       which escape the current function.
-                            if typeck.node_types().iter().any(|(_, &ty)| ty.is_unsafe_ptr())
+                            if typeck.node_types().items().any(|(_, &ty)| ty.is_unsafe_ptr())
                                 || typeck
                                     .adjustments()
-                                    .iter()
+                                    .items()
                                     .flat_map(|(_, a)| a)
                                     .any(|a| matches!(a.kind, Adjust::Pointer(PointerCast::UnsafeFnPointer)))
                             {
diff --git a/src/tools/clippy/clippy_utils/src/ty.rs b/src/tools/clippy/clippy_utils/src/ty.rs
index c8d56a3be5c..99fba4fe741 100644
--- a/src/tools/clippy/clippy_utils/src/ty.rs
+++ b/src/tools/clippy/clippy_utils/src/ty.rs
@@ -647,8 +647,8 @@ pub fn ty_sig<'tcx>(cx: &LateContext<'tcx>, ty: Ty<'tcx>) -> Option<ExprFnSig<'t
             Some(ExprFnSig::Closure(decl, subs.as_closure().sig()))
         },
         ty::FnDef(id, subs) => Some(ExprFnSig::Sig(cx.tcx.bound_fn_sig(id).subst(cx.tcx, subs), Some(id))),
-        ty::Alias(ty::Opaque, ty::AliasTy { def_id, .. }) => {
-            sig_from_bounds(cx, ty, cx.tcx.item_bounds(def_id), cx.tcx.opt_parent(def_id))
+        ty::Alias(ty::Opaque, ty::AliasTy { def_id, substs, .. }) => {
+            sig_from_bounds(cx, ty, cx.tcx.item_bounds(def_id).subst(cx.tcx, substs), cx.tcx.opt_parent(def_id))
         },
         ty::FnPtr(sig) => Some(ExprFnSig::Sig(sig, None)),
         ty::Dynamic(bounds, _, _) => {
diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index a5f5eb447da..3676f69b100 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -123,6 +123,7 @@ pub enum FailMode {
 pub enum CompareMode {
     Polonius,
     Chalk,
+    NextSolver,
     SplitDwarf,
     SplitDwarfSingle,
 }
@@ -132,6 +133,7 @@ impl CompareMode {
         match *self {
             CompareMode::Polonius => "polonius",
             CompareMode::Chalk => "chalk",
+            CompareMode::NextSolver => "next-solver",
             CompareMode::SplitDwarf => "split-dwarf",
             CompareMode::SplitDwarfSingle => "split-dwarf-single",
         }
@@ -141,6 +143,7 @@ impl CompareMode {
         match s.as_str() {
             "polonius" => CompareMode::Polonius,
             "chalk" => CompareMode::Chalk,
+            "next-solver" => CompareMode::NextSolver,
             "split-dwarf" => CompareMode::SplitDwarf,
             "split-dwarf-single" => CompareMode::SplitDwarfSingle,
             x => panic!("unknown --compare-mode option: {}", x),
diff --git a/src/tools/compiletest/src/header.rs b/src/tools/compiletest/src/header.rs
index c5767a79538..45fd87bea9b 100644
--- a/src/tools/compiletest/src/header.rs
+++ b/src/tools/compiletest/src/header.rs
@@ -162,6 +162,9 @@ pub struct TestProps {
     pub stderr_per_bitwidth: bool,
     // The MIR opt to unit test, if any
     pub mir_unit_test: Option<String>,
+    // Whether to tell `rustc` to remap the "src base" directory to a fake
+    // directory.
+    pub remap_src_base: bool,
 }
 
 mod directives {
@@ -196,6 +199,7 @@ mod directives {
     pub const INCREMENTAL: &'static str = "incremental";
     pub const KNOWN_BUG: &'static str = "known-bug";
     pub const MIR_UNIT_TEST: &'static str = "unit-test";
+    pub const REMAP_SRC_BASE: &'static str = "remap-src-base";
     // This isn't a real directive, just one that is probably mistyped often
     pub const INCORRECT_COMPILER_FLAGS: &'static str = "compiler-flags";
 }
@@ -241,6 +245,7 @@ impl TestProps {
             should_ice: false,
             stderr_per_bitwidth: false,
             mir_unit_test: None,
+            remap_src_base: false,
         }
     }
 
@@ -273,6 +278,9 @@ impl TestProps {
     /// `//[foo]`), then the property is ignored unless `cfg` is
     /// `Some("foo")`.
     fn load_from(&mut self, testfile: &Path, cfg: Option<&str>, config: &Config) {
+        // Mode-dependent defaults.
+        self.remap_src_base = config.mode == Mode::Ui && !config.suite.contains("rustdoc");
+
         let mut has_edition = false;
         if !testfile.is_dir() {
             let file = File::open(testfile).unwrap();
@@ -426,13 +434,19 @@ impl TestProps {
                         self.known_bug = true;
                     } else {
                         panic!(
-                            "Invalid known-bug value: {known_bug}\nIt requires comma-separated issue references (`#000` or `chalk#000`) or `unknown`."
+                            "Invalid known-bug value: {known_bug}\nIt requires comma-separated issue references (`#000` or `chalk#000`) or `known-bug: unknown`."
                         );
                     }
+                } else if config.parse_name_directive(ln, KNOWN_BUG) {
+                    panic!(
+                        "Invalid known-bug attribute, requires comma-separated issue references (`#000` or `chalk#000`) or `known-bug: unknown`."
+                    );
                 }
+
                 config.set_name_value_directive(ln, MIR_UNIT_TEST, &mut self.mir_unit_test, |s| {
                     s.trim().to_string()
                 });
+                config.set_name_directive(ln, REMAP_SRC_BASE, &mut self.remap_src_base);
             });
         }
 
@@ -696,6 +710,7 @@ impl Config {
             match self.compare_mode {
                 Some(CompareMode::Polonius) => name == "compare-mode-polonius",
                 Some(CompareMode::Chalk) => name == "compare-mode-chalk",
+                Some(CompareMode::NextSolver) => name == "compare-mode-next-solver",
                 Some(CompareMode::SplitDwarf) => name == "compare-mode-split-dwarf",
                 Some(CompareMode::SplitDwarfSingle) => name == "compare-mode-split-dwarf-single",
                 None => false,
@@ -725,6 +740,10 @@ impl Config {
             && matches!(line.as_bytes().get(directive.len()), None | Some(&b' ') | Some(&b':'))
     }
 
+    fn parse_negative_name_directive(&self, line: &str, directive: &str) -> bool {
+        line.starts_with("no-") && self.parse_name_directive(&line[3..], directive)
+    }
+
     pub fn parse_name_value_directive(&self, line: &str, directive: &str) -> Option<String> {
         let colon = directive.len();
         if line.starts_with(directive) && line.as_bytes().get(colon) == Some(&b':') {
@@ -754,8 +773,17 @@ impl Config {
     }
 
     fn set_name_directive(&self, line: &str, directive: &str, value: &mut bool) {
-        if !*value {
-            *value = self.parse_name_directive(line, directive)
+        match value {
+            true => {
+                if self.parse_negative_name_directive(line, directive) {
+                    *value = false;
+                }
+            }
+            false => {
+                if self.parse_name_directive(line, directive) {
+                    *value = true;
+                }
+            }
         }
     }
 
@@ -898,7 +926,7 @@ pub fn make_test_description<R: Read>(
     cfg: Option<&str>,
 ) -> test::TestDesc {
     let mut ignore = false;
-    let ignore_message = None;
+    let mut ignore_message = None;
     let mut should_fail = false;
 
     let rustc_has_profiler_support = env::var_os("RUSTC_PROFILER_SUPPORT").is_some();
@@ -938,41 +966,67 @@ pub fn make_test_description<R: Read>(
         if revision.is_some() && revision != cfg {
             return;
         }
+        macro_rules! reason {
+            ($e:expr) => {
+                ignore |= match $e {
+                    true => {
+                        ignore_message = Some(stringify!($e));
+                        true
+                    }
+                    false => ignore,
+                }
+            };
+        }
         ignore = match config.parse_cfg_name_directive(ln, "ignore") {
-            ParsedNameDirective::Match => true,
+            ParsedNameDirective::Match => {
+                ignore_message = Some("cfg -> ignore => Match");
+                true
+            }
             ParsedNameDirective::NoMatch => ignore,
         };
+
         if config.has_cfg_prefix(ln, "only") {
             ignore = match config.parse_cfg_name_directive(ln, "only") {
                 ParsedNameDirective::Match => ignore,
-                ParsedNameDirective::NoMatch => true,
+                ParsedNameDirective::NoMatch => {
+                    ignore_message = Some("cfg -> only => NoMatch");
+                    true
+                }
             };
         }
-        ignore |= ignore_llvm(config, ln);
-        ignore |=
-            config.run_clang_based_tests_with.is_none() && config.parse_needs_matching_clang(ln);
-        ignore |= !has_asm_support && config.parse_name_directive(ln, "needs-asm-support");
-        ignore |= !rustc_has_profiler_support && config.parse_needs_profiler_support(ln);
-        ignore |= !config.run_enabled() && config.parse_name_directive(ln, "needs-run-enabled");
-        ignore |= !rustc_has_sanitizer_support
-            && config.parse_name_directive(ln, "needs-sanitizer-support");
-        ignore |= !has_asan && config.parse_name_directive(ln, "needs-sanitizer-address");
-        ignore |= !has_cfi && config.parse_name_directive(ln, "needs-sanitizer-cfi");
-        ignore |= !has_kcfi && config.parse_name_directive(ln, "needs-sanitizer-kcfi");
-        ignore |= !has_lsan && config.parse_name_directive(ln, "needs-sanitizer-leak");
-        ignore |= !has_msan && config.parse_name_directive(ln, "needs-sanitizer-memory");
-        ignore |= !has_tsan && config.parse_name_directive(ln, "needs-sanitizer-thread");
-        ignore |= !has_hwasan && config.parse_name_directive(ln, "needs-sanitizer-hwaddress");
-        ignore |= !has_memtag && config.parse_name_directive(ln, "needs-sanitizer-memtag");
-        ignore |= !has_shadow_call_stack
-            && config.parse_name_directive(ln, "needs-sanitizer-shadow-call-stack");
-        ignore |= !config.can_unwind() && config.parse_name_directive(ln, "needs-unwind");
-        ignore |= config.target == "wasm32-unknown-unknown"
-            && config.parse_name_directive(ln, directives::CHECK_RUN_RESULTS);
-        ignore |= config.debugger == Some(Debugger::Cdb) && ignore_cdb(config, ln);
-        ignore |= config.debugger == Some(Debugger::Gdb) && ignore_gdb(config, ln);
-        ignore |= config.debugger == Some(Debugger::Lldb) && ignore_lldb(config, ln);
-        ignore |= !has_rust_lld && config.parse_name_directive(ln, "needs-rust-lld");
+
+        reason!(ignore_llvm(config, ln));
+        reason!(
+            config.run_clang_based_tests_with.is_none() && config.parse_needs_matching_clang(ln)
+        );
+        reason!(!has_asm_support && config.parse_name_directive(ln, "needs-asm-support"));
+        reason!(!rustc_has_profiler_support && config.parse_needs_profiler_support(ln));
+        reason!(!config.run_enabled() && config.parse_name_directive(ln, "needs-run-enabled"));
+        reason!(
+            !rustc_has_sanitizer_support
+                && config.parse_name_directive(ln, "needs-sanitizer-support")
+        );
+        reason!(!has_asan && config.parse_name_directive(ln, "needs-sanitizer-address"));
+        reason!(!has_cfi && config.parse_name_directive(ln, "needs-sanitizer-cfi"));
+        reason!(!has_kcfi && config.parse_name_directive(ln, "needs-sanitizer-kcfi"));
+        reason!(!has_lsan && config.parse_name_directive(ln, "needs-sanitizer-leak"));
+        reason!(!has_msan && config.parse_name_directive(ln, "needs-sanitizer-memory"));
+        reason!(!has_tsan && config.parse_name_directive(ln, "needs-sanitizer-thread"));
+        reason!(!has_hwasan && config.parse_name_directive(ln, "needs-sanitizer-hwaddress"));
+        reason!(!has_memtag && config.parse_name_directive(ln, "needs-sanitizer-memtag"));
+        reason!(
+            !has_shadow_call_stack
+                && config.parse_name_directive(ln, "needs-sanitizer-shadow-call-stack")
+        );
+        reason!(!config.can_unwind() && config.parse_name_directive(ln, "needs-unwind"));
+        reason!(
+            config.target == "wasm32-unknown-unknown"
+                && config.parse_name_directive(ln, directives::CHECK_RUN_RESULTS)
+        );
+        reason!(config.debugger == Some(Debugger::Cdb) && ignore_cdb(config, ln));
+        reason!(config.debugger == Some(Debugger::Gdb) && ignore_gdb(config, ln));
+        reason!(config.debugger == Some(Debugger::Lldb) && ignore_lldb(config, ln));
+        reason!(!has_rust_lld && config.parse_name_directive(ln, "needs-rust-lld"));
         should_fail |= config.parse_name_directive(ln, "should-fail");
     });
 
diff --git a/src/tools/compiletest/src/main.rs b/src/tools/compiletest/src/main.rs
index 2aea30870ff..3092c656cd7 100644
--- a/src/tools/compiletest/src/main.rs
+++ b/src/tools/compiletest/src/main.rs
@@ -775,7 +775,7 @@ fn make_test_name(
 ) -> test::TestName {
     // Print the name of the file, relative to the repository root.
     // `src_base` looks like `/path/to/rust/tests/ui`
-    let root_directory = config.src_base.parent().unwrap().parent().unwrap().parent().unwrap();
+    let root_directory = config.src_base.parent().unwrap().parent().unwrap();
     let path = testpaths.file.strip_prefix(root_directory).unwrap();
     let debugger = match config.debugger {
         Some(d) => format!("-{}", d),
diff --git a/src/tools/compiletest/src/read2.rs b/src/tools/compiletest/src/read2.rs
index 7640e651744..a5dc6859732 100644
--- a/src/tools/compiletest/src/read2.rs
+++ b/src/tools/compiletest/src/read2.rs
@@ -110,9 +110,18 @@ impl ProcOutput {
     fn into_bytes(self) -> Vec<u8> {
         match self {
             ProcOutput::Full { bytes, .. } => bytes,
-            ProcOutput::Abbreviated { mut head, skipped, tail } => {
+            ProcOutput::Abbreviated { mut head, mut skipped, tail } => {
+                let mut tail = &*tail;
+
+                // Skip over '{' at the start of the tail, so we don't later wrongfully consider this as json.
+                // See <https://rust-lang.zulipchat.com/#narrow/stream/182449-t-compiler.2Fhelp/topic/Weird.20CI.20failure/near/321797811>
+                while tail.get(0) == Some(&b'{') {
+                    tail = &tail[1..];
+                    skipped += 1;
+                }
+
                 write!(&mut head, "\n\n<<<<<< SKIPPED {} BYTES >>>>>>\n\n", skipped).unwrap();
-                head.extend_from_slice(&tail);
+                head.extend_from_slice(tail);
                 head
             }
         }
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index a16ab11e2f9..51c9a27c83d 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -44,6 +44,8 @@ use debugger::{check_debugger_output, DebuggerCommands};
 #[cfg(test)]
 mod tests;
 
+const FAKE_SRC_BASE: &str = "fake-test-src-base";
+
 #[cfg(windows)]
 fn disable_error_reporting<F: FnOnce() -> R, R>(f: F) -> R {
     use std::sync::Mutex;
@@ -1328,12 +1330,19 @@ impl<'test> TestCx<'test> {
             return;
         }
 
+        // On Windows, translate all '\' path separators to '/'
+        let file_name = format!("{}", self.testpaths.file.display()).replace(r"\", "/");
+
         // On Windows, keep all '\' path separators to match the paths reported in the JSON output
         // from the compiler
-        let os_file_name = self.testpaths.file.display().to_string();
-
-        // on windows, translate all '\' path separators to '/'
-        let file_name = format!("{}", self.testpaths.file.display()).replace(r"\", "/");
+        let diagnostic_file_name = if self.props.remap_src_base {
+            let mut p = PathBuf::from(FAKE_SRC_BASE);
+            p.push(&self.testpaths.relative_dir);
+            p.push(self.testpaths.file.file_name().unwrap());
+            p.display().to_string()
+        } else {
+            self.testpaths.file.display().to_string()
+        };
 
         // If the testcase being checked contains at least one expected "help"
         // message, then we'll ensure that all "help" messages are expected.
@@ -1343,7 +1352,7 @@ impl<'test> TestCx<'test> {
         let expect_note = expected_errors.iter().any(|ee| ee.kind == Some(ErrorKind::Note));
 
         // Parse the JSON output from the compiler and extract out the messages.
-        let actual_errors = json::parse_output(&os_file_name, &proc_res.stderr, proc_res);
+        let actual_errors = json::parse_output(&diagnostic_file_name, &proc_res.stderr, proc_res);
         let mut unexpected = Vec::new();
         let mut found = vec![false; expected_errors.len()];
         for actual_error in &actual_errors {
@@ -1970,6 +1979,14 @@ impl<'test> TestCx<'test> {
             }
         }
 
+        if self.props.remap_src_base {
+            rustc.arg(format!(
+                "--remap-path-prefix={}={}",
+                self.config.src_base.display(),
+                FAKE_SRC_BASE,
+            ));
+        }
+
         match emit {
             Emit::None => {}
             Emit::Metadata if is_rustdoc => {}
@@ -2013,6 +2030,9 @@ impl<'test> TestCx<'test> {
             Some(CompareMode::Chalk) => {
                 rustc.args(&["-Ztrait-solver=chalk"]);
             }
+            Some(CompareMode::NextSolver) => {
+                rustc.args(&["-Ztrait-solver=next"]);
+            }
             Some(CompareMode::SplitDwarf) if self.config.target.contains("windows") => {
                 rustc.args(&["-Csplit-debuginfo=unpacked", "-Zunstable-options"]);
             }
@@ -3545,6 +3565,14 @@ impl<'test> TestCx<'test> {
         let parent_dir = self.testpaths.file.parent().unwrap();
         normalize_path(parent_dir, "$DIR");
 
+        if self.props.remap_src_base {
+            let mut remapped_parent_dir = PathBuf::from(FAKE_SRC_BASE);
+            if self.testpaths.relative_dir != Path::new("") {
+                remapped_parent_dir.push(&self.testpaths.relative_dir);
+            }
+            normalize_path(&remapped_parent_dir, "$DIR");
+        }
+
         let source_bases = &[
             // Source base on the current filesystem (calculated as parent of `tests/$suite`):
             Some(self.config.src_base.parent().unwrap().parent().unwrap().into()),
diff --git a/src/tools/compiletest/src/util.rs b/src/tools/compiletest/src/util.rs
index 6c63b760ff6..ff7e8df9878 100644
--- a/src/tools/compiletest/src/util.rs
+++ b/src/tools/compiletest/src/util.rs
@@ -23,6 +23,7 @@ pub const ASAN_SUPPORTED_TARGETS: &[&str] = &[
     "x86_64-linux-android",
     "x86_64-unknown-freebsd",
     "x86_64-unknown-linux-gnu",
+    "s390x-unknown-linux-gnu",
 ];
 
 // FIXME(rcvalle): More targets are likely supported.
@@ -50,10 +51,15 @@ pub const LSAN_SUPPORTED_TARGETS: &[&str] = &[
     "aarch64-unknown-linux-gnu",
     "x86_64-apple-darwin",
     "x86_64-unknown-linux-gnu",
+    "s390x-unknown-linux-gnu",
 ];
 
-pub const MSAN_SUPPORTED_TARGETS: &[&str] =
-    &["aarch64-unknown-linux-gnu", "x86_64-unknown-freebsd", "x86_64-unknown-linux-gnu"];
+pub const MSAN_SUPPORTED_TARGETS: &[&str] = &[
+    "aarch64-unknown-linux-gnu",
+    "x86_64-unknown-freebsd",
+    "x86_64-unknown-linux-gnu",
+    "s390x-unknown-linux-gnu",
+];
 
 pub const TSAN_SUPPORTED_TARGETS: &[&str] = &[
     "aarch64-apple-darwin",
@@ -61,6 +67,7 @@ pub const TSAN_SUPPORTED_TARGETS: &[&str] = &[
     "x86_64-apple-darwin",
     "x86_64-unknown-freebsd",
     "x86_64-unknown-linux-gnu",
+    "s390x-unknown-linux-gnu",
 ];
 
 pub const HWASAN_SUPPORTED_TARGETS: &[&str] =
diff --git a/src/tools/miri/rust-version b/src/tools/miri/rust-version
index c0dbb2e644c..7a5e8b789da 100644
--- a/src/tools/miri/rust-version
+++ b/src/tools/miri/rust-version
@@ -1 +1 @@
-9e75dddf609c0201d03f9792e850f95d6a283d11
+a5fa99eed20a46a88c0c85eed6552a94b6656634
diff --git a/src/tools/miri/src/bin/miri.rs b/src/tools/miri/src/bin/miri.rs
index 6a147de3be2..c0267956aab 100644
--- a/src/tools/miri/src/bin/miri.rs
+++ b/src/tools/miri/src/bin/miri.rs
@@ -56,12 +56,12 @@ impl rustc_driver::Callbacks for MiriCompilerCalls {
 
     fn after_analysis<'tcx>(
         &mut self,
-        compiler: &rustc_interface::interface::Compiler,
+        _: &rustc_interface::interface::Compiler,
         queries: &'tcx rustc_interface::Queries<'tcx>,
     ) -> Compilation {
-        compiler.session().abort_if_errors();
-
         queries.global_ctxt().unwrap().enter(|tcx| {
+            tcx.sess.abort_if_errors();
+
             init_late_loggers(tcx);
             if !tcx.sess.crate_types().contains(&CrateType::Executable) {
                 tcx.sess.fatal("miri only makes sense on bin crates");
@@ -75,7 +75,7 @@ impl rustc_driver::Callbacks for MiriCompilerCalls {
             let mut config = self.miri_config.clone();
 
             // Add filename to `miri` arguments.
-            config.args.insert(0, compiler.input().filestem().to_string());
+            config.args.insert(0, tcx.sess.io.input.filestem().to_string());
 
             // Adjust working directory for interpretation.
             if let Some(cwd) = env::var_os("MIRI_CWD") {
@@ -87,10 +87,9 @@ impl rustc_driver::Callbacks for MiriCompilerCalls {
                     i32::try_from(return_code).expect("Return value was too large!"),
                 );
             }
+            tcx.sess.abort_if_errors();
         });
 
-        compiler.session().abort_if_errors();
-
         Compilation::Stop
     }
 }
diff --git a/src/tools/miri/tests/pass/vec.rs b/src/tools/miri/tests/pass/vec.rs
index 3a6655e2ba6..30a28bc5803 100644
--- a/src/tools/miri/tests/pass/vec.rs
+++ b/src/tools/miri/tests/pass/vec.rs
@@ -162,6 +162,11 @@ fn reverse() {
     assert!(v[0].0 == 49);
 }
 
+fn miri_issue_2759() {
+    let mut input = "1".to_string();
+    input.replace_range(0..0, "0");
+}
+
 fn main() {
     assert_eq!(vec_reallocate().len(), 5);
 
@@ -191,4 +196,5 @@ fn main() {
     swap();
     swap_remove();
     reverse();
+    miri_issue_2759();
 }
diff --git a/src/tools/tidy/Cargo.toml b/src/tools/tidy/Cargo.toml
index 19812fc6f55..cdf1dd36604 100644
--- a/src/tools/tidy/Cargo.toml
+++ b/src/tools/tidy/Cargo.toml
@@ -12,6 +12,7 @@ miropt-test-tools = { path = "../miropt-test-tools" }
 lazy_static = "1"
 walkdir = "2"
 ignore = "0.4.18"
+semver = "1.0"
 termcolor = "1.1.3"
 
 [[bin]]
diff --git a/src/tools/tidy/src/error_codes.rs b/src/tools/tidy/src/error_codes.rs
index bc9fd35ecde..5b84b51a035 100644
--- a/src/tools/tidy/src/error_codes.rs
+++ b/src/tools/tidy/src/error_codes.rs
@@ -27,8 +27,7 @@ const ERROR_DOCS_PATH: &str = "compiler/rustc_error_codes/src/error_codes/";
 const ERROR_TESTS_PATH: &str = "tests/ui/error-codes/";
 
 // Error codes that (for some reason) can't have a doctest in their explanation. Error codes are still expected to provide a code example, even if untested.
-const IGNORE_DOCTEST_CHECK: &[&str] =
-    &["E0208", "E0464", "E0570", "E0601", "E0602", "E0640", "E0717"];
+const IGNORE_DOCTEST_CHECK: &[&str] = &["E0464", "E0570", "E0601", "E0602", "E0640", "E0717"];
 
 // Error codes that don't yet have a UI test. This list will eventually be removed.
 const IGNORE_UI_TEST_CHECK: &[&str] =
diff --git a/src/tools/tidy/src/lib.rs b/src/tools/tidy/src/lib.rs
index 40375f1306d..35000320d1a 100644
--- a/src/tools/tidy/src/lib.rs
+++ b/src/tools/tidy/src/lib.rs
@@ -62,6 +62,7 @@ pub mod features;
 pub mod mir_opt_tests;
 pub mod pal;
 pub mod primitive_docs;
+pub mod rustdoc_gui_tests;
 pub mod style;
 pub mod target_specific_tests;
 pub mod tests_placement;
@@ -69,3 +70,4 @@ pub mod ui_tests;
 pub mod unit_tests;
 pub mod unstable_book;
 pub mod walk;
+pub mod x_version;
diff --git a/src/tools/tidy/src/main.rs b/src/tools/tidy/src/main.rs
index ea2886a3c2f..505f9d724c8 100644
--- a/src/tools/tidy/src/main.rs
+++ b/src/tools/tidy/src/main.rs
@@ -60,7 +60,7 @@ fn main() {
 
                 let handle = s.spawn(|| {
                     let mut flag = false;
-                    $p::check($($args),* , &mut flag);
+                    $p::check($($args, )* &mut flag);
                     if (flag) {
                         bad.store(true, Ordering::Relaxed);
                     }
@@ -80,6 +80,7 @@ fn main() {
         check!(debug_artifacts, &tests_path);
         check!(ui_tests, &tests_path);
         check!(mir_opt_tests, &tests_path, bless);
+        check!(rustdoc_gui_tests, &tests_path);
 
         // Checks that only make sense for the compiler.
         check!(error_codes, &root_path, &[&compiler_path, &librustdoc_path], verbose);
@@ -113,6 +114,8 @@ fn main() {
         check!(alphabetical, &compiler_path);
         check!(alphabetical, &library_path);
 
+        check!(x_version, &root_path, &cargo);
+
         let collected = {
             drain_handles(&mut handles);
 
diff --git a/src/tools/tidy/src/rustdoc_gui_tests.rs b/src/tools/tidy/src/rustdoc_gui_tests.rs
new file mode 100644
index 00000000000..feb513df34b
--- /dev/null
+++ b/src/tools/tidy/src/rustdoc_gui_tests.rs
@@ -0,0 +1,33 @@
+//! Tidy check to ensure that rustdoc GUI tests start with a small description.
+
+use std::path::Path;
+
+pub fn check(path: &Path, bad: &mut bool) {
+    crate::walk::walk(
+        &path.join("rustdoc-gui"),
+        &mut |p| {
+            // If there is no extension, it's very likely a folder and we want to go into it.
+            p.extension().map(|e| e != "goml").unwrap_or(false)
+        },
+        &mut |entry, content| {
+            for line in content.lines() {
+                if !line.starts_with("// ") {
+                    tidy_error!(
+                        bad,
+                        "{}: rustdoc-gui tests must start with a small description",
+                        entry.path().display(),
+                    );
+                    return;
+                } else if line.starts_with("// ") {
+                    let parts = line[2..].trim();
+                    // We ignore tidy comments.
+                    if parts.starts_with("// tidy-") {
+                        continue;
+                    }
+                    // All good!
+                    return;
+                }
+            }
+        },
+    );
+}
diff --git a/src/tools/tidy/src/x_version.rs b/src/tools/tidy/src/x_version.rs
new file mode 100644
index 00000000000..c470d502a65
--- /dev/null
+++ b/src/tools/tidy/src/x_version.rs
@@ -0,0 +1,68 @@
+use semver::Version;
+use std::path::Path;
+use std::process::{Command, Stdio};
+
+pub fn check(root: &Path, cargo: &Path, bad: &mut bool) {
+    let cargo_list = Command::new(cargo).args(["install", "--list"]).stdout(Stdio::piped()).spawn();
+
+    let child = match cargo_list {
+        Ok(child) => child,
+        Err(e) => return tidy_error!(bad, "failed to run `cargo`: {}", e),
+    };
+
+    let cargo_list = child.wait_with_output().unwrap();
+
+    if cargo_list.status.success() {
+        let exe_list = String::from_utf8_lossy(&cargo_list.stdout);
+        let exe_list = exe_list.lines();
+
+        let mut installed: Option<Version> = None;
+
+        for line in exe_list {
+            let mut iter = line.split_whitespace();
+            if iter.next() == Some("x") {
+                if let Some(version) = iter.next() {
+                    // Check this is the rust-lang/rust x tool installation since it should be
+                    // installed at a path containing `src/tools/x`.
+                    if let Some(path) = iter.next() {
+                        if path.contains(&"src/tools/x") {
+                            let version = version.strip_prefix("v").unwrap();
+                            installed = Some(Version::parse(version).unwrap());
+                            break;
+                        }
+                    };
+                }
+            } else {
+                continue;
+            }
+        }
+        // Unwrap the some if x is installed, otherwise return because it's fine if x isn't installed.
+        let installed = if let Some(i) = installed { i } else { return };
+
+        if let Some(expected) = get_x_wrapper_version(root, cargo) {
+            if installed < expected {
+                return println!(
+                    "Current version of x is {installed}, but the latest version is {expected}\nConsider updating to the newer version of x by running `cargo install --path src/tools/x`"
+                );
+            }
+        } else {
+            return tidy_error!(
+                bad,
+                "Unable to parse the latest version of `x` at `src/tools/x/Cargo.toml`"
+            );
+        }
+    } else {
+        return tidy_error!(bad, "failed to check version of `x`: {}", cargo_list.status);
+    }
+}
+
+// Parse latest version out of `x` Cargo.toml
+fn get_x_wrapper_version(root: &Path, cargo: &Path) -> Option<Version> {
+    let mut cmd = cargo_metadata::MetadataCommand::new();
+    cmd.cargo_path(cargo)
+        .manifest_path(root.join("src/tools/x/Cargo.toml"))
+        .no_deps()
+        .features(cargo_metadata::CargoOpt::AllFeatures);
+    let mut metadata = t!(cmd.exec());
+    metadata.packages.pop().map(|x| x.version)
+}
diff --git a/src/version b/src/version
index ee2f4ca9130..49349856550 100644
--- a/src/version
+++ b/src/version
@@ -1 +1 @@
-1.68.0
+1.69.0
diff --git a/tests/assembly/is_aligned.rs b/tests/assembly/is_aligned.rs
index 04b5de83423..620a3da9463 100644
--- a/tests/assembly/is_aligned.rs
+++ b/tests/assembly/is_aligned.rs
@@ -1,5 +1,5 @@
 // assembly-output: emit-asm
-// min-llvm-version: 14.0
+// min-llvm-version: 15.0
 // only-x86_64
 // revisions: opt-speed opt-size
 // [opt-speed] compile-flags: -Copt-level=1
diff --git a/tests/codegen/abi-sysv64.rs b/tests/codegen/abi-sysv64.rs
index dfc31227908..3c2d4e719d4 100644
--- a/tests/codegen/abi-sysv64.rs
+++ b/tests/codegen/abi-sysv64.rs
@@ -3,7 +3,7 @@
 // of the sysv64 abi.
 //
 // needs-llvm-components: x86
-// compile-flags: -C no-prepopulate-passes --target=x86_64-unknown-linux-gnu
+// compile-flags: -C no-prepopulate-passes --target=x86_64-unknown-linux-gnu -Copt-level=0
 
 #![crate_type = "lib"]
 #![no_core]
diff --git a/tests/codegen/abi-x86-interrupt.rs b/tests/codegen/abi-x86-interrupt.rs
index d612f603e4f..928ad5a9bbd 100644
--- a/tests/codegen/abi-x86-interrupt.rs
+++ b/tests/codegen/abi-x86-interrupt.rs
@@ -3,7 +3,7 @@
 // of the x86-interrupt abi.
 
 // needs-llvm-components: x86
-// compile-flags: -C no-prepopulate-passes --target=x86_64-unknown-linux-gnu
+// compile-flags: -C no-prepopulate-passes --target=x86_64-unknown-linux-gnu -Copt-level=0
 
 #![crate_type = "lib"]
 #![no_core]
diff --git a/tests/codegen/adjustments.rs b/tests/codegen/adjustments.rs
index 39880c9341f..6d224751752 100644
--- a/tests/codegen/adjustments.rs
+++ b/tests/codegen/adjustments.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C no-prepopulate-passes
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
 
 #![crate_type = "lib"]
 
diff --git a/tests/codegen/box-maybe-uninit-llvm14.rs b/tests/codegen/box-maybe-uninit-llvm14.rs
index 7b5ae894311..b0c88f76c43 100644
--- a/tests/codegen/box-maybe-uninit-llvm14.rs
+++ b/tests/codegen/box-maybe-uninit-llvm14.rs
@@ -31,4 +31,4 @@ pub fn box_uninitialized2() -> Box<MaybeUninit<[usize; 1024 * 1024]>> {
 // Hide the LLVM 15+ `allocalign` attribute in the declaration of __rust_alloc
 // from the CHECK-NOT above. We don't check the attributes here because we can't rely
 // on all of them being set until LLVM 15.
-// CHECK: declare noalias{{.*}} @__rust_alloc(i{{[0-9]+}}, i{{[0-9]+.*}})
+// CHECK: declare noalias{{.*}} @__rust_alloc(i{{[0-9]+}} noundef, i{{[0-9]+.*}} noundef)
diff --git a/tests/codegen/box-maybe-uninit.rs b/tests/codegen/box-maybe-uninit.rs
index c82b56a71f5..2f88966996a 100644
--- a/tests/codegen/box-maybe-uninit.rs
+++ b/tests/codegen/box-maybe-uninit.rs
@@ -28,6 +28,6 @@ pub fn box_uninitialized2() -> Box<MaybeUninit<[usize; 1024 * 1024]>> {
 
 // Hide the `allocalign` attribute in the declaration of __rust_alloc
 // from the CHECK-NOT above, and also verify the attributes got set reasonably.
-// CHECK: declare noalias ptr @__rust_alloc(i{{[0-9]+}}, i{{[0-9]+}} allocalign) unnamed_addr [[RUST_ALLOC_ATTRS:#[0-9]+]]
+// CHECK: declare noalias noundef ptr @__rust_alloc(i{{[0-9]+}} noundef, i{{[0-9]+}} allocalign noundef) unnamed_addr [[RUST_ALLOC_ATTRS:#[0-9]+]]
 
 // CHECK-DAG: attributes [[RUST_ALLOC_ATTRS]] = { {{.*}} allockind("alloc,uninitialized,aligned") allocsize(0) uwtable "alloc-family"="__rust_alloc" {{.*}} }
diff --git a/tests/codegen/c-variadic.rs b/tests/codegen/c-variadic.rs
index a5be56c47be..cab32652210 100644
--- a/tests/codegen/c-variadic.rs
+++ b/tests/codegen/c-variadic.rs
@@ -1,5 +1,5 @@
 // ignore-wasm32-bare compiled with panic=abort by default
-// compile-flags: -C no-prepopulate-passes
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
 //
 
 #![crate_type = "lib"]
diff --git a/tests/codegen/call-llvm-intrinsics.rs b/tests/codegen/call-llvm-intrinsics.rs
index 998099c2390..cb8abae198e 100644
--- a/tests/codegen/call-llvm-intrinsics.rs
+++ b/tests/codegen/call-llvm-intrinsics.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C no-prepopulate-passes
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
 
 // ignore-riscv64
 
diff --git a/tests/codegen/comparison-operators-newtype.rs b/tests/codegen/comparison-operators-newtype.rs
index 5cf6c3ac0a2..683a2bd4fbb 100644
--- a/tests/codegen/comparison-operators-newtype.rs
+++ b/tests/codegen/comparison-operators-newtype.rs
@@ -13,7 +13,7 @@ use std::cmp::Ordering;
 pub struct Foo(u16);
 
 // CHECK-LABEL: @check_lt
-// CHECK-SAME: (i16 %[[A:.+]], i16 %[[B:.+]])
+// CHECK-SAME: (i16 noundef %[[A:.+]], i16 noundef %[[B:.+]])
 #[no_mangle]
 pub fn check_lt(a: Foo, b: Foo) -> bool {
     // CHECK: %[[R:.+]] = icmp ult i16 %[[A]], %[[B]]
@@ -22,7 +22,7 @@ pub fn check_lt(a: Foo, b: Foo) -> bool {
 }
 
 // CHECK-LABEL: @check_le
-// CHECK-SAME: (i16 %[[A:.+]], i16 %[[B:.+]])
+// CHECK-SAME: (i16 noundef %[[A:.+]], i16 noundef %[[B:.+]])
 #[no_mangle]
 pub fn check_le(a: Foo, b: Foo) -> bool {
     // CHECK: %[[R:.+]] = icmp ule i16 %[[A]], %[[B]]
@@ -31,7 +31,7 @@ pub fn check_le(a: Foo, b: Foo) -> bool {
 }
 
 // CHECK-LABEL: @check_gt
-// CHECK-SAME: (i16 %[[A:.+]], i16 %[[B:.+]])
+// CHECK-SAME: (i16 noundef %[[A:.+]], i16 noundef %[[B:.+]])
 #[no_mangle]
 pub fn check_gt(a: Foo, b: Foo) -> bool {
     // CHECK: %[[R:.+]] = icmp ugt i16 %[[A]], %[[B]]
@@ -40,7 +40,7 @@ pub fn check_gt(a: Foo, b: Foo) -> bool {
 }
 
 // CHECK-LABEL: @check_ge
-// CHECK-SAME: (i16 %[[A:.+]], i16 %[[B:.+]])
+// CHECK-SAME: (i16 noundef %[[A:.+]], i16 noundef %[[B:.+]])
 #[no_mangle]
 pub fn check_ge(a: Foo, b: Foo) -> bool {
     // CHECK: %[[R:.+]] = icmp uge i16 %[[A]], %[[B]]
diff --git a/tests/codegen/dllimports/main.rs b/tests/codegen/dllimports/main.rs
index ab599992ffd..383940e9590 100644
--- a/tests/codegen/dllimports/main.rs
+++ b/tests/codegen/dllimports/main.rs
@@ -1,4 +1,4 @@
-// This test is for *-windows-msvc only.
+ // This test is for *-windows-msvc only.
 // only-windows
 // ignore-gnu
 
@@ -15,10 +15,10 @@ extern crate wrapper;
 // CHECK: @static_global1 = external local_unnamed_addr global i32
 // CHECK: @static_global2 = external local_unnamed_addr global i32
 
-// CHECK: declare dllimport i32 @dylib_func1(i32)
-// CHECK: declare dllimport i32 @dylib_func2(i32)
-// CHECK: declare i32 @static_func1(i32)
-// CHECK: declare i32 @static_func2(i32)
+// CHECK: declare dllimport noundef i32 @dylib_func1(i32 noundef)
+// CHECK: declare dllimport noundef i32 @dylib_func2(i32 noundef)
+// CHECK: declare noundef i32 @static_func1(i32 noundef)
+// CHECK: declare noundef i32 @static_func2(i32 noundef)
 
 #[link(name = "dummy", kind="dylib")]
 extern "C" {
diff --git a/tests/codegen/enum-match.rs b/tests/codegen/enum-match.rs
index 827eb20154a..5f8063a27f7 100644
--- a/tests/codegen/enum-match.rs
+++ b/tests/codegen/enum-match.rs
@@ -11,7 +11,7 @@ pub enum Enum0 {
     B,
 }
 
-// CHECK: define i8 @match0{{.*}}
+// CHECK: define noundef i8 @match0{{.*}}
 // CHECK-NEXT: start:
 // CHECK-NEXT: %1 = icmp eq i8 %0, 2
 // CHECK-NEXT: %2 = and i8 %0, 1
@@ -32,7 +32,7 @@ pub enum Enum1 {
     C,
 }
 
-// CHECK: define i8 @match1{{.*}}
+// CHECK: define noundef i8 @match1{{.*}}
 // CHECK-NEXT: start:
 // CHECK-NEXT: [[DISCR:%.*]] = {{.*}}call i8 @llvm.usub.sat.i8(i8 %0, i8 1)
 // CHECK-NEXT: switch i8 [[DISCR]], label {{.*}} [
@@ -88,7 +88,7 @@ pub enum Enum2 {
     E,
 }
 
-// CHECK: define i8 @match2{{.*}}
+// CHECK: define noundef i8 @match2{{.*}}
 // CHECK-NEXT: start:
 // CHECK-NEXT: %1 = add i8 %0, 2
 // CHECK-NEXT: %2 = zext i8 %1 to i64
diff --git a/tests/codegen/fastcall-inreg.rs b/tests/codegen/fastcall-inreg.rs
index d426ade28dd..02f5d545910 100644
--- a/tests/codegen/fastcall-inreg.rs
+++ b/tests/codegen/fastcall-inreg.rs
@@ -15,27 +15,27 @@ trait Sized {}
 trait Copy {}
 
 pub mod tests {
-    // CHECK: @f1(i32 inreg %_1, i32 inreg %_2, i32 %_3)
+    // CHECK: @f1(i32 inreg noundef %_1, i32 inreg noundef %_2, i32 noundef %_3)
     #[no_mangle]
     pub extern "fastcall" fn f1(_: i32, _: i32, _: i32) {}
 
-    // CHECK: @f2({{i32\*|ptr}} inreg %_1, {{i32\*|ptr}} inreg %_2, {{i32\*|ptr}} %_3)
+    // CHECK: @f2({{i32\*|ptr}} inreg noundef %_1, {{i32\*|ptr}} inreg noundef %_2, {{i32\*|ptr}} noundef %_3)
     #[no_mangle]
     pub extern "fastcall" fn f2(_: *const i32, _: *const i32, _: *const i32) {}
 
-    // CHECK: @f3(float %_1, i32 inreg %_2, i32 inreg %_3, i32 %_4)
+    // CHECK: @f3(float noundef %_1, i32 inreg noundef %_2, i32 inreg noundef %_3, i32 noundef %_4)
     #[no_mangle]
     pub extern "fastcall" fn f3(_: f32, _: i32, _: i32, _: i32) {}
 
-    // CHECK: @f4(i32 inreg %_1, float %_2, i32 inreg %_3, i32 %_4)
+    // CHECK: @f4(i32 inreg noundef %_1, float noundef %_2, i32 inreg noundef %_3, i32 noundef %_4)
     #[no_mangle]
     pub extern "fastcall" fn f4(_: i32, _: f32, _: i32, _: i32) {}
 
-    // CHECK: @f5(i64 %_1, i32 %_2)
+    // CHECK: @f5(i64 noundef %_1, i32 noundef %_2)
     #[no_mangle]
     pub extern "fastcall" fn f5(_: i64, _: i32) {}
 
-    // CHECK: @f6(i1 inreg noundef zeroext %_1, i32 inreg %_2, i32 %_3)
+    // CHECK: @f6(i1 inreg noundef zeroext %_1, i32 inreg noundef %_2, i32 noundef %_3)
     #[no_mangle]
     pub extern "fastcall" fn f6(_: bool, _: i32, _: i32) {}
 }
diff --git a/tests/codegen/fewer-names.rs b/tests/codegen/fewer-names.rs
index 7307e0379df..ac8cba06b48 100644
--- a/tests/codegen/fewer-names.rs
+++ b/tests/codegen/fewer-names.rs
@@ -7,11 +7,11 @@
 
 #[no_mangle]
 pub fn sum(x: u32, y: u32) -> u32 {
-// YES-LABEL: define{{.*}}i32 @sum(i32 %0, i32 %1)
+// YES-LABEL: define{{.*}}i32 @sum(i32 noundef %0, i32 noundef %1)
 // YES-NEXT:    %3 = add i32 %1, %0
 // YES-NEXT:    ret i32 %3
 
-// NO-LABEL: define{{.*}}i32 @sum(i32 %x, i32 %y)
+// NO-LABEL: define{{.*}}i32 @sum(i32 noundef %x, i32 noundef %y)
 // NO-NEXT:  start:
 // NO-NEXT:    %z = add i32 %y, %x
 // NO-NEXT:    ret i32 %z
diff --git a/tests/codegen/frame-pointer.rs b/tests/codegen/frame-pointer.rs
index f7c02d47939..d8933262e52 100644
--- a/tests/codegen/frame-pointer.rs
+++ b/tests/codegen/frame-pointer.rs
@@ -1,4 +1,4 @@
-// compile-flags: --crate-type=rlib
+// compile-flags: --crate-type=rlib -Copt-level=0
 // revisions: aarch64-apple aarch64-linux force x64-apple x64-linux
 // [aarch64-apple] needs-llvm-components: aarch64
 // [aarch64-apple] compile-flags: --target=aarch64-apple-darwin
diff --git a/tests/codegen/function-arguments.rs b/tests/codegen/function-arguments.rs
index 0f9e90f6ba7..1f979d7b90a 100644
--- a/tests/codegen/function-arguments.rs
+++ b/tests/codegen/function-arguments.rs
@@ -1,11 +1,11 @@
 // compile-flags: -O -C no-prepopulate-passes
 
 #![crate_type = "lib"]
-#![feature(rustc_attrs)]
 
 use std::mem::MaybeUninit;
 use std::num::NonZeroU64;
 use std::marker::PhantomPinned;
+use std::ptr::NonNull;
 
 pub struct S {
   _field: [i32; 8],
@@ -61,7 +61,7 @@ pub fn maybeuninit_char(x: MaybeUninit<char>) -> MaybeUninit<char> {
   x
 }
 
-// CHECK: i64 @int(i64 %x)
+// CHECK: noundef i64 @int(i64 noundef %x)
 #[no_mangle]
 pub fn int(x: u64) -> u64 {
   x
@@ -73,7 +73,7 @@ pub fn nonzero_int(x: NonZeroU64) -> NonZeroU64 {
   x
 }
 
-// CHECK: i64 @option_nonzero_int(i64 %x)
+// CHECK: noundef i64 @option_nonzero_int(i64 noundef %x)
 #[no_mangle]
 pub fn option_nonzero_int(x: Option<NonZeroU64>) -> Option<NonZeroU64> {
   x
@@ -138,11 +138,27 @@ pub fn indirect_struct(_: S) {
 pub fn borrowed_struct(_: &S) {
 }
 
-// CHECK: @raw_struct({{%S\*|ptr}} %_1)
+// CHECK: @option_borrow({{i32\*|ptr}} noalias noundef readonly align 4 dereferenceable_or_null(4) %x)
+#[no_mangle]
+pub fn option_borrow(x: Option<&i32>) {
+}
+
+// CHECK: @option_borrow_mut({{i32\*|ptr}} noalias noundef align 4 dereferenceable_or_null(4) %x)
+#[no_mangle]
+pub fn option_borrow_mut(x: Option<&mut i32>) {
+}
+
+// CHECK: @raw_struct({{%S\*|ptr}} noundef %_1)
 #[no_mangle]
 pub fn raw_struct(_: *const S) {
 }
 
+// CHECK: @raw_option_nonnull_struct({{i32\*|ptr}} noundef %_1)
+#[no_mangle]
+pub fn raw_option_nonnull_struct(_: Option<NonNull<S>>) {
+}
+
+
 // `Box` can get deallocated during execution of the function, so it should
 // not get `dereferenceable`.
 // CHECK: noundef nonnull align 4 {{i32\*|ptr}} @_box({{i32\*|ptr}} noalias noundef nonnull align 4 %x)
@@ -160,35 +176,35 @@ pub fn struct_return() -> S {
 }
 
 // Hack to get the correct size for the length part in slices
-// CHECK: @helper([[USIZE:i[0-9]+]] %_1)
+// CHECK: @helper([[USIZE:i[0-9]+]] noundef %_1)
 #[no_mangle]
 pub fn helper(_: usize) {
 }
 
-// CHECK: @slice({{\[0 x i8\]\*|ptr}} noalias noundef nonnull readonly align 1 %_1.0, [[USIZE]] %_1.1)
+// CHECK: @slice({{\[0 x i8\]\*|ptr}} noalias noundef nonnull readonly align 1 %_1.0, [[USIZE]] noundef %_1.1)
 // FIXME #25759 This should also have `nocapture`
 #[no_mangle]
 pub fn slice(_: &[u8]) {
 }
 
-// CHECK: @mutable_slice({{\[0 x i8\]\*|ptr}} noalias noundef nonnull align 1 %_1.0, [[USIZE]] %_1.1)
+// CHECK: @mutable_slice({{\[0 x i8\]\*|ptr}} noalias noundef nonnull align 1 %_1.0, [[USIZE]] noundef %_1.1)
 // FIXME #25759 This should also have `nocapture`
 #[no_mangle]
 pub fn mutable_slice(_: &mut [u8]) {
 }
 
-// CHECK: @unsafe_slice({{\[0 x i16\]\*|ptr}} noundef nonnull align 2 %_1.0, [[USIZE]] %_1.1)
+// CHECK: @unsafe_slice({{\[0 x i16\]\*|ptr}} noundef nonnull align 2 %_1.0, [[USIZE]] noundef %_1.1)
 // unsafe interior means this isn't actually readonly and there may be aliases ...
 #[no_mangle]
 pub fn unsafe_slice(_: &[UnsafeInner]) {
 }
 
-// CHECK: @raw_slice({{\[0 x i8\]\*|ptr}} %_1.0, [[USIZE]] %_1.1)
+// CHECK: @raw_slice({{\[0 x i8\]\*|ptr}} noundef %_1.0, [[USIZE]] noundef %_1.1)
 #[no_mangle]
 pub fn raw_slice(_: *const [u8]) {
 }
 
-// CHECK: @str({{\[0 x i8\]\*|ptr}} noalias noundef nonnull readonly align 1 %_1.0, [[USIZE]] %_1.1)
+// CHECK: @str({{\[0 x i8\]\*|ptr}} noalias noundef nonnull readonly align 1 %_1.0, [[USIZE]] noundef %_1.1)
 // FIXME #25759 This should also have `nocapture`
 #[no_mangle]
 pub fn str(_: &[u8]) {
@@ -197,26 +213,36 @@ pub fn str(_: &[u8]) {
 // CHECK: @trait_borrow({{\{\}\*|ptr}} noundef nonnull align 1 %_1.0, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}) %_1.1)
 // FIXME #25759 This should also have `nocapture`
 #[no_mangle]
-pub fn trait_borrow(_: &Drop) {
+pub fn trait_borrow(_: &dyn Drop) {
+}
+
+// CHECK: @option_trait_borrow({{i8\*|ptr}} noundef align 1 %x.0, {{i8\*|ptr}} %x.1)
+#[no_mangle]
+pub fn option_trait_borrow(x: Option<&dyn Drop>) {
+}
+
+// CHECK: @option_trait_borrow_mut({{i8\*|ptr}} noundef align 1 %x.0, {{i8\*|ptr}} %x.1)
+#[no_mangle]
+pub fn option_trait_borrow_mut(x: Option<&mut dyn Drop>) {
 }
 
-// CHECK: @trait_raw({{\{\}\*|ptr}} %_1.0, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}) %_1.1)
+// CHECK: @trait_raw({{\{\}\*|ptr}} noundef %_1.0, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}) %_1.1)
 #[no_mangle]
-pub fn trait_raw(_: *const Drop) {
+pub fn trait_raw(_: *const dyn Drop) {
 }
 
 // CHECK: @trait_box({{\{\}\*|ptr}} noalias noundef nonnull align 1{{( %0)?}}, {{.+}} noalias noundef readonly align {{.*}} dereferenceable({{.*}}){{( %1)?}})
 #[no_mangle]
-pub fn trait_box(_: Box<Drop>) {
+pub fn trait_box(_: Box<dyn Drop>) {
 }
 
 // CHECK: { {{i8\*|ptr}}, {{i8\*|ptr}} } @trait_option({{i8\*|ptr}} noalias noundef align 1 %x.0, {{i8\*|ptr}} %x.1)
 #[no_mangle]
-pub fn trait_option(x: Option<Box<Drop>>) -> Option<Box<Drop>> {
+pub fn trait_option(x: Option<Box<dyn Drop>>) -> Option<Box<dyn Drop>> {
   x
 }
 
-// CHECK: { {{\[0 x i16\]\*|ptr}}, [[USIZE]] } @return_slice({{\[0 x i16\]\*|ptr}} noalias noundef nonnull readonly align 2 %x.0, [[USIZE]] %x.1)
+// CHECK: { {{\[0 x i16\]\*|ptr}}, [[USIZE]] } @return_slice({{\[0 x i16\]\*|ptr}} noalias noundef nonnull readonly align 2 %x.0, [[USIZE]] noundef %x.1)
 #[no_mangle]
 pub fn return_slice(x: &[u16]) -> &[u16] {
   x
diff --git a/tests/codegen/intrinsics/const_eval_select.rs b/tests/codegen/intrinsics/const_eval_select.rs
index db8a04763d3..f3877dc6b96 100644
--- a/tests/codegen/intrinsics/const_eval_select.rs
+++ b/tests/codegen/intrinsics/const_eval_select.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C no-prepopulate-passes
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
 
 #![crate_type = "lib"]
 #![feature(const_eval_select)]
diff --git a/tests/codegen/intrinsics/mask.rs b/tests/codegen/intrinsics/mask.rs
index 2e984db1be5..8f93da2e5da 100644
--- a/tests/codegen/intrinsics/mask.rs
+++ b/tests/codegen/intrinsics/mask.rs
@@ -1,3 +1,4 @@
+// compile-flags: -Copt-level=0
 #![crate_type = "lib"]
 #![feature(core_intrinsics)]
 
@@ -6,6 +7,6 @@
 #[no_mangle]
 pub fn mask_ptr(ptr: *const u16, mask: usize) -> *const u16 {
     // CHECK: call
-    // CHECK-SAME: @llvm.ptrmask.{{p0|p0i8}}.[[WORD]]({{ptr|i8\*}} {{%ptr|%0}}, [[WORD]] %mask)
+    // CHECK-SAME: @llvm.ptrmask.{{p0|p0i8}}.[[WORD]]({{ptr|i8\*}} {{%ptr|%1}}, [[WORD]] %mask)
     core::intrinsics::ptr_mask(ptr, mask)
 }
diff --git a/tests/codegen/issue-32031.rs b/tests/codegen/issue-32031.rs
index 82ba325572a..abef92c19b6 100644
--- a/tests/codegen/issue-32031.rs
+++ b/tests/codegen/issue-32031.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C no-prepopulate-passes
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
 
 #![crate_type = "lib"]
 
diff --git a/tests/codegen/issue-45964-bounds-check-slice-pos.rs b/tests/codegen/issue-45964-bounds-check-slice-pos.rs
index aa59c713b78..1daa213fc82 100644
--- a/tests/codegen/issue-45964-bounds-check-slice-pos.rs
+++ b/tests/codegen/issue-45964-bounds-check-slice-pos.rs
@@ -2,6 +2,7 @@
 // prevent optimizing away bounds checks
 
 // compile-flags: -O
+// ignore-debug: the debug assertions get in the way
 
 #![crate_type="rlib"]
 
diff --git a/tests/codegen/issue-58881.rs b/tests/codegen/issue-58881.rs
index 0900a33377b..00f8953d949 100644
--- a/tests/codegen/issue-58881.rs
+++ b/tests/codegen/issue-58881.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C no-prepopulate-passes
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
 //
 // only-x86_64
 // ignore-windows
diff --git a/tests/codegen/issue-96497-slice-size-nowrap.rs b/tests/codegen/issue-96497-slice-size-nowrap.rs
index a5dbef93460..0413ed6b26f 100644
--- a/tests/codegen/issue-96497-slice-size-nowrap.rs
+++ b/tests/codegen/issue-96497-slice-size-nowrap.rs
@@ -3,7 +3,7 @@
 // in some situations, see https://github.com/rust-lang/rust/issues/96497#issuecomment-1112865218
 
 // compile-flags: -O
-// min-llvm-version: 14.0
+// min-llvm-version: 15.0
 
 #![crate_type="lib"]
 
diff --git a/tests/codegen/iter-repeat-n-trivial-drop.rs b/tests/codegen/iter-repeat-n-trivial-drop.rs
index 20e1d9b4d59..24059f190ac 100644
--- a/tests/codegen/iter-repeat-n-trivial-drop.rs
+++ b/tests/codegen/iter-repeat-n-trivial-drop.rs
@@ -46,7 +46,7 @@ pub fn iter_repeat_n_next(it: &mut std::iter::RepeatN<NotCopy>) -> Option<NotCop
 #[no_mangle]
 // CHECK-LABEL: @vec_extend_via_iter_repeat_n
 pub fn vec_extend_via_iter_repeat_n() -> Vec<u8> {
-    // CHECK: %[[ADDR:.+]] = tail call dereferenceable_or_null(1234) ptr @__rust_alloc(i64 1234, i64 1)
+    // CHECK: %[[ADDR:.+]] = tail call noundef dereferenceable_or_null(1234) ptr @__rust_alloc(i64 noundef 1234, i64 noundef 1)
     // CHECK: tail call void @llvm.memset.p0.i64(ptr noundef nonnull align 1 dereferenceable(1234) %[[ADDR]], i8 42, i64 1234,
 
     let n = 1234_usize;
diff --git a/tests/codegen/loads.rs b/tests/codegen/loads.rs
index f448306ba1b..f29a26596bf 100644
--- a/tests/codegen/loads.rs
+++ b/tests/codegen/loads.rs
@@ -50,8 +50,8 @@ pub fn load_scalar_pair<'a>(x: &(&'a i32, &'a Align16)) -> (&'a i32, &'a Align16
 // CHECK-LABEL: @load_raw_pointer
 #[no_mangle]
 pub fn load_raw_pointer<'a>(x: &*const i32) -> *const i32 {
-    // loaded raw pointer should not have !nonnull, !align, or !noundef metadata
-    // CHECK: load {{i32\*|ptr}}, {{i32\*\*|ptr}} %x, align [[PTR_ALIGNMENT]]{{$}}
+    // loaded raw pointer should not have !nonnull or !align metadata
+    // CHECK: load {{i32\*|ptr}}, {{i32\*\*|ptr}} %x, align [[PTR_ALIGNMENT]], !noundef ![[NOUNDEF:[0-9]+]]{{$}}
     *x
 }
 
@@ -93,7 +93,7 @@ pub fn load_maybeuninit_enum_bool(x: &MaybeUninit<MyBool>) -> MaybeUninit<MyBool
 // CHECK-LABEL: @load_int
 #[no_mangle]
 pub fn load_int(x: &u16) -> u16 {
-    // CHECK: load i16, {{i16\*|ptr}} %x, align 2{{$}}
+    // CHECK: load i16, {{i16\*|ptr}} %x, align 2, !noundef ![[NOUNDEF]]{{$}}
     *x
 }
 
@@ -107,7 +107,7 @@ pub fn load_nonzero_int(x: &NonZeroU16) -> NonZeroU16 {
 // CHECK-LABEL: @load_option_nonzero_int
 #[no_mangle]
 pub fn load_option_nonzero_int(x: &Option<NonZeroU16>) -> Option<NonZeroU16> {
-    // CHECK: load i16, {{i16\*|ptr}} %x, align 2{{$}}
+    // CHECK: load i16, {{i16\*|ptr}} %x, align 2, !noundef ![[NOUNDEF]]{{$}}
     *x
 }
 
diff --git a/tests/codegen/naked-functions.rs b/tests/codegen/naked-functions.rs
index 51c7a0c615d..e05bbc26e83 100644
--- a/tests/codegen/naked-functions.rs
+++ b/tests/codegen/naked-functions.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C no-prepopulate-passes
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
 // needs-asm-support
 // only-x86_64
 
diff --git a/tests/codegen/pic-relocation-model.rs b/tests/codegen/pic-relocation-model.rs
index 602a08067ba..518e949ffe3 100644
--- a/tests/codegen/pic-relocation-model.rs
+++ b/tests/codegen/pic-relocation-model.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C relocation-model=pic
+// compile-flags: -C relocation-model=pic -Copt-level=0
 
 #![crate_type = "rlib"]
 
diff --git a/tests/codegen/pie-relocation-model.rs b/tests/codegen/pie-relocation-model.rs
index ec44edc0667..941cca922bd 100644
--- a/tests/codegen/pie-relocation-model.rs
+++ b/tests/codegen/pie-relocation-model.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C relocation-model=pie
+// compile-flags: -C relocation-model=pie -Copt-level=0
 // only-x86_64-unknown-linux-gnu
 
 #![crate_type = "rlib"]
diff --git a/tests/codegen/refs.rs b/tests/codegen/refs.rs
index 0b796754d1d..a5289766711 100644
--- a/tests/codegen/refs.rs
+++ b/tests/codegen/refs.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C no-prepopulate-passes -Zmir-opt-level=0
+// compile-flags: -C no-prepopulate-passes -Zmir-opt-level=0 -Copt-level=0
 
 #![crate_type = "lib"]
 
diff --git a/tests/codegen/repr-transparent.rs b/tests/codegen/repr-transparent.rs
index 4f2313ce47a..311cbfbaa09 100644
--- a/tests/codegen/repr-transparent.rs
+++ b/tests/codegen/repr-transparent.rs
@@ -18,21 +18,21 @@ pub struct Zst2(());
 #[repr(transparent)]
 pub struct F32(f32);
 
-// CHECK: define{{.*}}float @test_F32(float %_1)
+// CHECK: define{{.*}}float @test_F32(float noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_F32(_: F32) -> F32 { loop {} }
 
 #[repr(transparent)]
 pub struct Ptr(*mut u8);
 
-// CHECK: define{{.*}}{{i8\*|ptr}} @test_Ptr({{i8\*|ptr}} %_1)
+// CHECK: define{{.*}}{{i8\*|ptr}} @test_Ptr({{i8\*|ptr}} noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_Ptr(_: Ptr) -> Ptr { loop {} }
 
 #[repr(transparent)]
 pub struct WithZst(u64, Zst1);
 
-// CHECK: define{{.*}}i64 @test_WithZst(i64 %_1)
+// CHECK: define{{.*}}i64 @test_WithZst(i64 noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_WithZst(_: WithZst) -> WithZst { loop {} }
 
@@ -40,14 +40,14 @@ pub extern "C" fn test_WithZst(_: WithZst) -> WithZst { loop {} }
 pub struct WithZeroSizedArray(*const f32, [i8; 0]);
 
 // Apparently we use i32* when newtype-unwrapping f32 pointers. Whatever.
-// CHECK: define{{.*}}{{i32\*|ptr}} @test_WithZeroSizedArray({{i32\*|ptr}} %_1)
+// CHECK: define{{.*}}{{i32\*|ptr}} @test_WithZeroSizedArray({{i32\*|ptr}} noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_WithZeroSizedArray(_: WithZeroSizedArray) -> WithZeroSizedArray { loop {} }
 
 #[repr(transparent)]
 pub struct Generic<T>(T);
 
-// CHECK: define{{.*}}double @test_Generic(double %_1)
+// CHECK: define{{.*}}double @test_Generic(double noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_Generic(_: Generic<f64>) -> Generic<f64> { loop {} }
 
@@ -64,7 +64,7 @@ pub extern "C" fn test_Gpz(_: GenericPlusZst<Bool>) -> GenericPlusZst<Bool> { lo
 #[repr(transparent)]
 pub struct LifetimePhantom<'a, T: 'a>(*const T, PhantomData<&'a T>);
 
-// CHECK: define{{.*}}{{i16\*|ptr}} @test_LifetimePhantom({{i16\*|ptr}} %_1)
+// CHECK: define{{.*}}{{i16\*|ptr}} @test_LifetimePhantom({{i16\*|ptr}} noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_LifetimePhantom(_: LifetimePhantom<i16>) -> LifetimePhantom<i16> { loop {} }
 
@@ -74,28 +74,28 @@ pub struct UnitPhantom<T, U> { val: T, unit: PhantomData<U> }
 
 pub struct Px;
 
-// CHECK: define{{.*}}float @test_UnitPhantom(float %_1)
+// CHECK: define{{.*}}float @test_UnitPhantom(float noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_UnitPhantom(_: UnitPhantom<f32, Px>) -> UnitPhantom<f32, Px> { loop {} }
 
 #[repr(transparent)]
 pub struct TwoZsts(Zst1, i8, Zst2);
 
-// CHECK: define{{( dso_local)?}}{{( signext)?}} i8 @test_TwoZsts(i8{{( signext)?}} %_1)
+// CHECK: define{{( dso_local)?}} noundef{{( signext)?}} i8 @test_TwoZsts(i8 noundef{{( signext)?}} %_1)
 #[no_mangle]
 pub extern "C" fn test_TwoZsts(_: TwoZsts) -> TwoZsts { loop {} }
 
 #[repr(transparent)]
 pub struct Nested1(Zst2, Generic<f64>);
 
-// CHECK: define{{.*}}double @test_Nested1(double %_1)
+// CHECK: define{{.*}}double @test_Nested1(double noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_Nested1(_: Nested1) -> Nested1 { loop {} }
 
 #[repr(transparent)]
 pub struct Nested2(Nested1, Zst1);
 
-// CHECK: define{{.*}}double @test_Nested2(double %_1)
+// CHECK: define{{.*}}double @test_Nested2(double noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_Nested2(_: Nested2) -> Nested2 { loop {} }
 
@@ -115,7 +115,7 @@ impl<T: ?Sized> Mirror for T { type It = Self; }
 #[repr(transparent)]
 pub struct StructWithProjection(<f32 as Mirror>::It);
 
-// CHECK: define{{.*}}float @test_Projection(float %_1)
+// CHECK: define{{.*}}float @test_Projection(float noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_Projection(_: StructWithProjection) -> StructWithProjection { loop {} }
 
@@ -124,7 +124,7 @@ pub enum EnumF32 {
     Variant(F32)
 }
 
-// CHECK: define{{.*}}float @test_EnumF32(float %_1)
+// CHECK: define{{.*}}float @test_EnumF32(float noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_EnumF32(_: EnumF32) -> EnumF32 { loop {} }
 
@@ -133,7 +133,7 @@ pub enum EnumF32WithZsts {
     Variant(Zst1, F32, Zst2)
 }
 
-// CHECK: define{{.*}}float @test_EnumF32WithZsts(float %_1)
+// CHECK: define{{.*}}float @test_EnumF32WithZsts(float noundef %_1)
 #[no_mangle]
 pub extern "C" fn test_EnumF32WithZsts(_: EnumF32WithZsts) -> EnumF32WithZsts { loop {} }
 
@@ -142,7 +142,7 @@ pub union UnionF32 {
     field: F32,
 }
 
-// CHECK: define{{.*}}float @test_UnionF32(float %_1)
+// CHECK: define{{.*}} float @test_UnionF32(float %_1)
 #[no_mangle]
 pub extern "C" fn test_UnionF32(_: UnionF32) -> UnionF32 { loop {} }
 
diff --git a/tests/codegen/riscv-abi/riscv64-lp64-lp64f-lp64d-abi.rs b/tests/codegen/riscv-abi/riscv64-lp64-lp64f-lp64d-abi.rs
index 61c4b7b51af..045f01985a5 100644
--- a/tests/codegen/riscv-abi/riscv64-lp64-lp64f-lp64d-abi.rs
+++ b/tests/codegen/riscv-abi/riscv64-lp64-lp64f-lp64d-abi.rs
@@ -29,25 +29,25 @@ pub extern "C" fn f_scalar_0(a: bool) -> bool {
     a
 }
 
-// CHECK: define signext i8 @f_scalar_1(i8 signext %x)
+// CHECK: define noundef signext i8 @f_scalar_1(i8 noundef signext %x)
 #[no_mangle]
 pub extern "C" fn f_scalar_1(x: i8) -> i8 {
     x
 }
 
-// CHECK: define zeroext i8 @f_scalar_2(i8 zeroext %x)
+// CHECK: define noundef zeroext i8 @f_scalar_2(i8 noundef zeroext %x)
 #[no_mangle]
 pub extern "C" fn f_scalar_2(x: u8) -> u8 {
     x
 }
 
-// CHECK: define signext i32 @f_scalar_3(i32 signext %x)
+// CHECK: define noundef signext i32 @f_scalar_3(i32 noundef signext %x)
 #[no_mangle]
 pub extern "C" fn f_scalar_3(x: i32) -> u32 {
     x as u32
 }
 
-// CHECK: define i64 @f_scalar_4(i64 %x)
+// CHECK: define noundef i64 @f_scalar_4(i64 noundef %x)
 #[no_mangle]
 pub extern "C" fn f_scalar_4(x: i64) -> i64 {
     x
@@ -132,13 +132,13 @@ pub struct Large {
 pub extern "C" fn f_agg_large(mut x: Large) {
 }
 
-// CHECK: define void @f_agg_large_ret({{%Large\*|ptr}} {{.*}}sret{{.*}}, i32 signext %i, i8 signext %j)
+// CHECK: define void @f_agg_large_ret({{%Large\*|ptr}} {{.*}}sret{{.*}}, i32 noundef signext %i, i8 noundef signext %j)
 #[no_mangle]
 pub extern "C" fn f_agg_large_ret(i: i32, j: i8) -> Large {
     Large { a: 1, b: 2, c: 3, d: 4 }
 }
 
-// CHECK: define void @f_scalar_stack_1(i64 %0, [2 x i64] %1, i128 %2, {{%Large\*|ptr}} {{.*}}%d, i8 zeroext %e, i8 signext %f, i8 %g, i8 %h)
+// CHECK: define void @f_scalar_stack_1(i64 %0, [2 x i64] %1, i128 %2, {{%Large\*|ptr}} {{.*}}%d, i8 noundef zeroext %e, i8 noundef signext %f, i8 noundef %g, i8 noundef %h)
 #[no_mangle]
 pub extern "C" fn f_scalar_stack_1(
     a: Tiny,
@@ -152,7 +152,7 @@ pub extern "C" fn f_scalar_stack_1(
 ) {
 }
 
-// CHECK: define void @f_scalar_stack_2({{%Large\*|ptr}} {{.*}}sret{{.*}} %0, i64 %a, i128 %1, i128 %2, i64 %d, i8 zeroext %e, i8 %f, i8 %g)
+// CHECK: define void @f_scalar_stack_2({{%Large\*|ptr}} {{.*}}sret{{.*}} %0, i64 noundef %a, i128 %1, i128 %2, i64 noundef %d, i8 noundef zeroext %e, i8 noundef %f, i8 noundef %g)
 #[no_mangle]
 pub extern "C" fn f_scalar_stack_2(
     a: u64,
@@ -172,7 +172,7 @@ extern "C" {
 
 #[no_mangle]
 pub unsafe extern "C" fn f_va_caller() {
-    // CHECK: call signext i32 (i32, ...) @f_va_callee(i32 signext 1, i32 signext 2, i64 3, double {{.*}}, double {{.*}}, i64 {{.*}}, [2 x i64] {{.*}}, i128 {{.*}}, {{%Large\*|ptr}} {{.*}})
+    // CHECK: call noundef signext i32 (i32, ...) @f_va_callee(i32 noundef signext 1, i32 noundef signext 2, i64 noundef 3, double {{.*}}, double {{.*}}, i64 {{.*}}, [2 x i64] {{.*}}, i128 {{.*}}, {{%Large\*|ptr}} {{.*}})
     f_va_callee(
         1,
         2i32,
@@ -184,6 +184,6 @@ pub unsafe extern "C" fn f_va_caller() {
         SmallAligned { a: 11 },
         Large { a: 12, b: 13, c: 14, d: 15 },
     );
-    // CHECK: call signext i32 (i32, ...) @f_va_callee(i32 signext 1, i32 signext 2, i32 signext 3, i32 signext 4, i128 {{.*}}, i32 signext 6, i32 signext 7, i32 8, i32 9)
+    // CHECK: call noundef signext i32 (i32, ...) @f_va_callee(i32 noundef signext 1, i32 noundef signext 2, i32 noundef signext 3, i32 noundef signext 4, i128 {{.*}}, i32 noundef signext 6, i32 noundef signext 7, i32 noundef 8, i32 noundef 9)
     f_va_callee(1, 2i32, 3i32, 4i32, SmallAligned { a: 5 }, 6i32, 7i32, 8i32, 9i32);
 }
diff --git a/tests/codegen/sanitizer-cfi-emit-type-checks.rs b/tests/codegen/sanitizer-cfi-emit-type-checks.rs
index 8be5186de9e..597b867ebad 100644
--- a/tests/codegen/sanitizer-cfi-emit-type-checks.rs
+++ b/tests/codegen/sanitizer-cfi-emit-type-checks.rs
@@ -1,7 +1,7 @@
 // Verifies that pointer type membership tests for indirect calls are emitted.
 //
 // needs-sanitizer-cfi
-// compile-flags: -Clto -Cno-prepopulate-passes -Ctarget-feature=-crt-static -Zsanitizer=cfi
+// compile-flags: -Clto -Cno-prepopulate-passes -Ctarget-feature=-crt-static -Zsanitizer=cfi -Copt-level=0
 
 #![crate_type="lib"]
 
diff --git a/tests/codegen/sanitizer-kcfi-emit-kcfi-operand-bundle-itanium-cxx-abi.rs b/tests/codegen/sanitizer-kcfi-emit-kcfi-operand-bundle-itanium-cxx-abi.rs
index 8e0d02550ee..2537df80a90 100644
--- a/tests/codegen/sanitizer-kcfi-emit-kcfi-operand-bundle-itanium-cxx-abi.rs
+++ b/tests/codegen/sanitizer-kcfi-emit-kcfi-operand-bundle-itanium-cxx-abi.rs
@@ -5,7 +5,7 @@
 // [aarch64] needs-llvm-components: aarch64
 // [x86_64] compile-flags: --target x86_64-unknown-none
 // [x86_64] needs-llvm-components:
-// compile-flags: -Cno-prepopulate-passes -Zsanitizer=kcfi
+// compile-flags: -Cno-prepopulate-passes -Zsanitizer=kcfi -Copt-level=0
 
 #![crate_type="lib"]
 #![feature(no_core, lang_items)]
diff --git a/tests/codegen/sanitizer-recover.rs b/tests/codegen/sanitizer-recover.rs
index 7ce0fa0a20f..7b00fcf8e1b 100644
--- a/tests/codegen/sanitizer-recover.rs
+++ b/tests/codegen/sanitizer-recover.rs
@@ -6,8 +6,8 @@
 // revisions:ASAN ASAN-RECOVER MSAN MSAN-RECOVER MSAN-RECOVER-LTO
 // no-prefer-dynamic
 //
-//[ASAN]             compile-flags: -Zsanitizer=address
-//[ASAN-RECOVER]     compile-flags: -Zsanitizer=address -Zsanitizer-recover=address
+//[ASAN]             compile-flags: -Zsanitizer=address -Copt-level=0
+//[ASAN-RECOVER]     compile-flags: -Zsanitizer=address -Zsanitizer-recover=address -Copt-level=0
 //[MSAN]             compile-flags: -Zsanitizer=memory
 //[MSAN-RECOVER]     compile-flags: -Zsanitizer=memory  -Zsanitizer-recover=memory
 //[MSAN-RECOVER-LTO] compile-flags: -Zsanitizer=memory  -Zsanitizer-recover=memory -C lto=fat
@@ -26,17 +26,17 @@
 // ASAN-RECOVER-NOT:     unreachable
 // ASAN:               }
 //
-// MSAN-LABEL: define dso_local i32 @penguin(
+// MSAN-LABEL: define dso_local noundef i32 @penguin(
 // MSAN:         call void @__msan_warning{{(_with_origin_noreturn\(i32 0\)|_noreturn\(\))}}
 // MSAN:         unreachable
 // MSAN:       }
 //
-// MSAN-RECOVER-LABEL: define dso_local i32 @penguin(
+// MSAN-RECOVER-LABEL: define dso_local noundef i32 @penguin(
 // MSAN-RECOVER:         call void @__msan_warning{{(_with_origin\(i32 0\)|\(\))}}
 // MSAN-RECOVER-NOT:     unreachable
 // MSAN-RECOVER:       }
 //
-// MSAN-RECOVER-LTO-LABEL: define dso_local i32 @penguin(
+// MSAN-RECOVER-LTO-LABEL: define dso_local noundef i32 @penguin(
 // MSAN-RECOVER-LTO:          call void @__msan_warning{{(_with_origin\(i32 0\)|\(\))}}
 // MSAN-RECOVER-LTO-NOT:      unreachable
 // MSAN-RECOVER-LTO:       }
diff --git a/tests/codegen/scalar-pair-bool.rs b/tests/codegen/scalar-pair-bool.rs
index 264f28fdb5f..8e8365b6a67 100644
--- a/tests/codegen/scalar-pair-bool.rs
+++ b/tests/codegen/scalar-pair-bool.rs
@@ -8,13 +8,13 @@ pub fn pair_bool_bool(pair: (bool, bool)) -> (bool, bool) {
     pair
 }
 
-// CHECK: define{{.*}}{ i8, i32 } @pair_bool_i32(i1 noundef zeroext %pair.0, i32 %pair.1)
+// CHECK: define{{.*}}{ i8, i32 } @pair_bool_i32(i1 noundef zeroext %pair.0, i32 noundef %pair.1)
 #[no_mangle]
 pub fn pair_bool_i32(pair: (bool, i32)) -> (bool, i32) {
     pair
 }
 
-// CHECK: define{{.*}}{ i32, i8 } @pair_i32_bool(i32 %pair.0, i1 noundef zeroext %pair.1)
+// CHECK: define{{.*}}{ i32, i8 } @pair_i32_bool(i32 noundef %pair.0, i1 noundef zeroext %pair.1)
 #[no_mangle]
 pub fn pair_i32_bool(pair: (i32, bool)) -> (i32, bool) {
     pair
diff --git a/tests/codegen/some-abis-do-extend-params-to-32-bits.rs b/tests/codegen/some-abis-do-extend-params-to-32-bits.rs
index 7fc34af3da7..9f2d9d06524 100644
--- a/tests/codegen/some-abis-do-extend-params-to-32-bits.rs
+++ b/tests/codegen/some-abis-do-extend-params-to-32-bits.rs
@@ -1,4 +1,4 @@
-// compile-flags: -Cno-prepopulate-passes
+// compile-flags: -Cno-prepopulate-passes -Copt-level=0
 
 // revisions:x86_64 i686 aarch64-apple aarch64-windows aarch64-linux arm riscv
 
diff --git a/tests/codegen/static-relocation-model-msvc.rs b/tests/codegen/static-relocation-model-msvc.rs
index b2afc7deb67..735ef7081c9 100644
--- a/tests/codegen/static-relocation-model-msvc.rs
+++ b/tests/codegen/static-relocation-model-msvc.rs
@@ -15,8 +15,8 @@ extern crate extern_decl;
 // it to be marked `dso_local` as well, given the static relocation model.
 //
 // CHECK: @extern_static = external dso_local local_unnamed_addr global i8
-// CHECK: define dso_local i8 @access_extern() {{.*}}
-// CHECK: declare dso_local i8 @extern_fn() {{.*}}
+// CHECK: define dso_local noundef i8 @access_extern() {{.*}}
+// CHECK: declare dso_local noundef i8 @extern_fn() {{.*}}
 
 #[no_mangle]
 pub fn access_extern() -> u8 {
diff --git a/tests/codegen/transmute-scalar.rs b/tests/codegen/transmute-scalar.rs
index a7e5deeffd8..260dcbac0fc 100644
--- a/tests/codegen/transmute-scalar.rs
+++ b/tests/codegen/transmute-scalar.rs
@@ -5,7 +5,7 @@
 // FIXME(eddyb) all of these tests show memory stores and loads, even after a
 // scalar `bitcast`, more special-casing is required to remove `alloca` usage.
 
-// CHECK-LABEL: define{{.*}}i32 @f32_to_bits(float %x)
+// CHECK-LABEL: define{{.*}}i32 @f32_to_bits(float noundef %x)
 // CHECK: store i32 %{{.*}}, {{.*}} %0
 // CHECK-NEXT: %[[RES:.*]] = load i32, {{.*}} %0
 // CHECK: ret i32 %[[RES]]
@@ -24,7 +24,7 @@ pub fn bool_to_byte(b: bool) -> u8 {
     unsafe { std::mem::transmute(b) }
 }
 
-// CHECK-LABEL: define{{.*}}noundef zeroext i1 @byte_to_bool(i8 %byte)
+// CHECK-LABEL: define{{.*}}noundef zeroext i1 @byte_to_bool(i8 noundef %byte)
 // CHECK: %1 = trunc i8 %byte to i1
 // CHECK-NEXT: %2 = zext i1 %1 to i8
 // CHECK-NEXT: store i8 %2, {{.*}} %0
@@ -36,7 +36,7 @@ pub unsafe fn byte_to_bool(byte: u8) -> bool {
     std::mem::transmute(byte)
 }
 
-// CHECK-LABEL: define{{.*}}{{i8\*|ptr}} @ptr_to_ptr({{i16\*|ptr}} %p)
+// CHECK-LABEL: define{{.*}}{{i8\*|ptr}} @ptr_to_ptr({{i16\*|ptr}} noundef %p)
 // CHECK: store {{i8\*|ptr}} %{{.*}}, {{.*}} %0
 // CHECK-NEXT: %[[RES:.*]] = load {{i8\*|ptr}}, {{.*}} %0
 // CHECK: ret {{i8\*|ptr}} %[[RES]]
@@ -52,7 +52,7 @@ pub fn ptr_to_ptr(p: *mut u16) -> *mut u8 {
 // Tests below show the non-special-cased behavior (with the possible
 // future special-cased instructions in the "NOTE(eddyb)" comments).
 
-// CHECK: define{{.*}}[[USIZE:i[0-9]+]] @ptr_to_int({{i16\*|ptr}} %p)
+// CHECK: define{{.*}}[[USIZE:i[0-9]+]] @ptr_to_int({{i16\*|ptr}} noundef %p)
 
 // NOTE(eddyb) see above, the following two CHECK lines should ideally be this:
 //        %2 = ptrtoint i16* %p to [[USIZE]]
@@ -66,7 +66,7 @@ pub fn ptr_to_int(p: *mut u16) -> usize {
     unsafe { std::mem::transmute(p) }
 }
 
-// CHECK: define{{.*}}{{i16\*|ptr}} @int_to_ptr([[USIZE]] %i)
+// CHECK: define{{.*}}{{i16\*|ptr}} @int_to_ptr([[USIZE]] noundef %i)
 
 // NOTE(eddyb) see above, the following two CHECK lines should ideally be this:
 //        %2 = inttoptr [[USIZE]] %i to i16*
diff --git a/tests/codegen/tuple-layout-opt.rs b/tests/codegen/tuple-layout-opt.rs
index e86c75f3f48..35f76085145 100644
--- a/tests/codegen/tuple-layout-opt.rs
+++ b/tests/codegen/tuple-layout-opt.rs
@@ -1,5 +1,5 @@
 // ignore-emscripten
-// compile-flags: -C no-prepopulate-passes
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
 
 // Test that tuples get optimized layout, in particular with a ZST in the last field (#63244)
 
diff --git a/tests/codegen/var-names.rs b/tests/codegen/var-names.rs
index 8f1b038708e..d4715efad73 100644
--- a/tests/codegen/var-names.rs
+++ b/tests/codegen/var-names.rs
@@ -2,7 +2,7 @@
 
 #![crate_type = "lib"]
 
-// CHECK-LABEL: define{{.*}}i32 @test(i32 %a, i32 %b)
+// CHECK-LABEL: define{{.*}}i32 @test(i32 noundef %a, i32 noundef %b)
 #[no_mangle]
 pub fn test(a: u32, b: u32) -> u32 {
     let c = a + b;
diff --git a/tests/codegen/vec-calloc.rs b/tests/codegen/vec-calloc.rs
index ae6e448f172..4481a9d1e99 100644
--- a/tests/codegen/vec-calloc.rs
+++ b/tests/codegen/vec-calloc.rs
@@ -161,7 +161,24 @@ pub fn vec_option_bool(n: usize) -> Vec<Option<bool>> {
     vec![Some(false); n]
 }
 
+// CHECK-LABEL: @vec_option_i32
+#[no_mangle]
+pub fn vec_option_i32(n: usize) -> Vec<Option<i32>> {
+    // CHECK-NOT: call {{.*}}alloc::vec::from_elem
+    // CHECK-NOT: call {{.*}}reserve
+    // CHECK-NOT: call {{.*}}__rust_alloc(
+
+    // CHECK: call {{.*}}__rust_alloc_zeroed(
+
+    // CHECK-NOT: call {{.*}}alloc::vec::from_elem
+    // CHECK-NOT: call {{.*}}reserve
+    // CHECK-NOT: call {{.*}}__rust_alloc(
+
+    // CHECK: ret void
+    vec![None; n]
+}
+
 // Ensure that __rust_alloc_zeroed gets the right attributes for LLVM to optimize it away.
-// CHECK: declare noalias ptr @__rust_alloc_zeroed(i64, i64 allocalign) unnamed_addr [[RUST_ALLOC_ZEROED_ATTRS:#[0-9]+]]
+// CHECK: declare noalias noundef ptr @__rust_alloc_zeroed(i64 noundef, i64 allocalign noundef) unnamed_addr [[RUST_ALLOC_ZEROED_ATTRS:#[0-9]+]]
 
 // CHECK-DAG: attributes [[RUST_ALLOC_ZEROED_ATTRS]] = { {{.*}} allockind("alloc,zeroed,aligned") allocsize(0) uwtable "alloc-family"="__rust_alloc" {{.*}} }
diff --git a/tests/codegen/zst-offset.rs b/tests/codegen/zst-offset.rs
index 844d5870a84..cef4b9bdaaf 100644
--- a/tests/codegen/zst-offset.rs
+++ b/tests/codegen/zst-offset.rs
@@ -1,4 +1,4 @@
-// compile-flags: -C no-prepopulate-passes
+// compile-flags: -C no-prepopulate-passes -Copt-level=0
 
 #![crate_type = "lib"]
 #![feature(repr_simd)]
diff --git a/tests/mir-opt/building/async_await.a-{closure#0}.generator_resume.0.mir b/tests/mir-opt/building/async_await.a-{closure#0}.generator_resume.0.mir
new file mode 100644
index 00000000000..2a7f90fe947
--- /dev/null
+++ b/tests/mir-opt/building/async_await.a-{closure#0}.generator_resume.0.mir
@@ -0,0 +1,41 @@
+// MIR for `a::{closure#0}` 0 generator_resume
+/* generator_layout = GeneratorLayout {
+    field_tys: {},
+    variant_fields: {
+        Unresumed(0): [],
+        Returned (1): [],
+        Panicked (2): [],
+    },
+    storage_conflicts: BitMatrix(0x0) {},
+} */
+
+fn a::{closure#0}(_1: Pin<&mut [async fn body@$DIR/async_await.rs:11:14: 11:16]>, _2: &mut Context<'_>) -> Poll<()> {
+    debug _task_context => _4;           // in scope 0 at $DIR/async_await.rs:+0:14: +0:16
+    let mut _0: std::task::Poll<()>;     // return place in scope 0 at $DIR/async_await.rs:+0:14: +0:16
+    let mut _3: ();                      // in scope 0 at $DIR/async_await.rs:+0:14: +0:16
+    let mut _4: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+0:14: +0:16
+    let mut _5: u32;                     // in scope 0 at $DIR/async_await.rs:+0:14: +0:16
+
+    bb0: {
+        _5 = discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:11:14: 11:16]))); // scope 0 at $DIR/async_await.rs:+0:14: +0:16
+        switchInt(move _5) -> [0: bb1, 1: bb2, otherwise: bb3]; // scope 0 at $DIR/async_await.rs:+0:14: +0:16
+    }
+
+    bb1: {
+        _4 = move _2;                    // scope 0 at $DIR/async_await.rs:+0:14: +0:16
+        _3 = const ();                   // scope 0 at $DIR/async_await.rs:+0:14: +0:16
+        Deinit(_0);                      // scope 0 at $DIR/async_await.rs:+0:16: +0:16
+        ((_0 as Ready).0: ()) = move _3; // scope 0 at $DIR/async_await.rs:+0:16: +0:16
+        discriminant(_0) = 0;            // scope 0 at $DIR/async_await.rs:+0:16: +0:16
+        discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:11:14: 11:16]))) = 1; // scope 0 at $DIR/async_await.rs:+0:16: +0:16
+        return;                          // scope 0 at $DIR/async_await.rs:+0:16: +0:16
+    }
+
+    bb2: {
+        assert(const false, "`async fn` resumed after completion") -> bb2; // scope 0 at $DIR/async_await.rs:+0:14: +0:16
+    }
+
+    bb3: {
+        unreachable;                     // scope 0 at $DIR/async_await.rs:+0:14: +0:16
+    }
+}
diff --git a/tests/mir-opt/building/async_await.b-{closure#0}.generator_resume.0.mir b/tests/mir-opt/building/async_await.b-{closure#0}.generator_resume.0.mir
new file mode 100644
index 00000000000..05edc4797d4
--- /dev/null
+++ b/tests/mir-opt/building/async_await.b-{closure#0}.generator_resume.0.mir
@@ -0,0 +1,337 @@
+// MIR for `b::{closure#0}` 0 generator_resume
+/* generator_layout = GeneratorLayout {
+    field_tys: {
+        _0: impl std::future::Future<Output = ()>,
+        _1: impl std::future::Future<Output = ()>,
+    },
+    variant_fields: {
+        Unresumed(0): [],
+        Returned (1): [],
+        Panicked (2): [],
+        Suspend0 (3): [_0],
+        Suspend1 (4): [_1],
+    },
+    storage_conflicts: BitMatrix(2x2) {
+        (_0, _0),
+        (_1, _1),
+    },
+} */
+
+fn b::{closure#0}(_1: Pin<&mut [async fn body@$DIR/async_await.rs:14:18: 17:2]>, _2: &mut Context<'_>) -> Poll<()> {
+    debug _task_context => _38;          // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    let mut _0: std::task::Poll<()>;     // return place in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    let _3: ();                          // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
+    let mut _4: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _5: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:5: +1:8
+    let mut _6: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _7: ();                      // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    let _8: ();                          // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _9: std::task::Poll<()>;     // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _10: std::pin::Pin<&mut impl std::future::Future<Output = ()>>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _11: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _12: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _13: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
+    let mut _14: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
+    let mut _15: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _16: isize;                  // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _18: !;                      // in scope 0 at $DIR/async_await.rs:+1:5: +1:14
+    let mut _19: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _20: ();                     // in scope 0 at $DIR/async_await.rs:+1:8: +1:14
+    let mut _21: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let mut _22: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:5: +2:8
+    let mut _23: impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let _24: ();                         // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let mut _25: std::task::Poll<()>;    // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let mut _26: std::pin::Pin<&mut impl std::future::Future<Output = ()>>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let mut _27: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let mut _28: &mut impl std::future::Future<Output = ()>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let mut _29: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:5: +2:14
+    let mut _30: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:5: +2:14
+    let mut _31: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let mut _32: isize;                  // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let mut _34: !;                      // in scope 0 at $DIR/async_await.rs:+2:5: +2:14
+    let mut _35: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let mut _36: ();                     // in scope 0 at $DIR/async_await.rs:+2:8: +2:14
+    let mut _37: ();                     // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    let mut _38: &mut std::task::Context<'_>; // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    let mut _39: u32;                    // in scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    scope 1 {
+        debug __awaitee => (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#3).0: impl std::future::Future<Output = ()>); // in scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        let _17: ();                     // in scope 1 at $DIR/async_await.rs:+1:5: +1:14
+        scope 2 {
+        }
+        scope 3 {
+            debug result => _17;         // in scope 3 at $DIR/async_await.rs:+1:5: +1:14
+        }
+    }
+    scope 4 {
+        debug __awaitee => (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#4).0: impl std::future::Future<Output = ()>); // in scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        let _33: ();                     // in scope 4 at $DIR/async_await.rs:+2:5: +2:14
+        scope 5 {
+        }
+        scope 6 {
+            debug result => _33;         // in scope 6 at $DIR/async_await.rs:+2:5: +2:14
+        }
+    }
+
+    bb0: {
+        _39 = discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))); // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        switchInt(move _39) -> [0: bb1, 1: bb29, 3: bb27, 4: bb28, otherwise: bb30]; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    }
+
+    bb1: {
+        _38 = move _2;                   // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        StorageLive(_3);                 // scope 0 at $DIR/async_await.rs:+1:5: +1:14
+        StorageLive(_4);                 // scope 0 at $DIR/async_await.rs:+1:8: +1:14
+        StorageLive(_5);                 // scope 0 at $DIR/async_await.rs:+1:5: +1:8
+        _5 = a() -> bb2;                 // scope 0 at $DIR/async_await.rs:+1:5: +1:8
+                                         // mir::Constant
+                                         // + span: $DIR/async_await.rs:15:5: 15:6
+                                         // + literal: Const { ty: fn() -> impl Future<Output = ()> {a}, val: Value(<ZST>) }
+    }
+
+    bb2: {
+        _4 = <impl Future<Output = ()> as IntoFuture>::into_future(move _5) -> bb3; // scope 0 at $DIR/async_await.rs:+1:8: +1:14
+                                         // mir::Constant
+                                         // + span: $DIR/async_await.rs:15:8: 15:14
+                                         // + literal: Const { ty: fn(impl Future<Output = ()>) -> <impl Future<Output = ()> as IntoFuture>::IntoFuture {<impl Future<Output = ()> as IntoFuture>::into_future}, val: Value(<ZST>) }
+    }
+
+    bb3: {
+        StorageDead(_5);                 // scope 0 at $DIR/async_await.rs:+1:13: +1:14
+        nop;                             // scope 0 at $DIR/async_await.rs:+1:8: +1:14
+        (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#3).0: impl std::future::Future<Output = ()>) = move _4; // scope 0 at $DIR/async_await.rs:+1:8: +1:14
+        goto -> bb4;                     // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+    }
+
+    bb4: {
+        StorageLive(_8);                 // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        StorageLive(_9);                 // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        StorageLive(_10);                // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+        StorageLive(_11);                // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+        StorageLive(_12);                // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+        _12 = &mut (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#3).0: impl std::future::Future<Output = ()>); // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+        _11 = &mut (*_12);               // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+        _10 = Pin::<&mut impl Future<Output = ()>>::new_unchecked(move _11) -> bb5; // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+                                         // mir::Constant
+                                         // + span: $DIR/async_await.rs:15:8: 15:14
+                                         // + literal: Const { ty: unsafe fn(&mut impl Future<Output = ()>) -> Pin<&mut impl Future<Output = ()>> {Pin::<&mut impl Future<Output = ()>>::new_unchecked}, val: Value(<ZST>) }
+    }
+
+    bb5: {
+        StorageDead(_11);                // scope 2 at $DIR/async_await.rs:+1:13: +1:14
+        StorageLive(_13);                // scope 2 at $DIR/async_await.rs:+1:5: +1:14
+        StorageLive(_14);                // scope 2 at $DIR/async_await.rs:+1:5: +1:14
+        StorageLive(_15);                // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+        _15 = _38;                       // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+        _14 = move _15;                  // scope 2 at $DIR/async_await.rs:+1:5: +1:14
+        goto -> bb6;                     // scope 2 at $DIR/async_await.rs:+1:5: +1:14
+    }
+
+    bb6: {
+        _13 = &mut (*_14);               // scope 2 at $DIR/async_await.rs:+1:5: +1:14
+        StorageDead(_15);                // scope 2 at $DIR/async_await.rs:+1:13: +1:14
+        _9 = <impl Future<Output = ()> as Future>::poll(move _10, move _13) -> bb7; // scope 2 at $DIR/async_await.rs:+1:8: +1:14
+                                         // mir::Constant
+                                         // + span: $DIR/async_await.rs:15:8: 15:14
+                                         // + literal: Const { ty: for<'a, 'b, 'c> fn(Pin<&'a mut impl Future<Output = ()>>, &'b mut Context<'c>) -> Poll<<impl Future<Output = ()> as Future>::Output> {<impl Future<Output = ()> as Future>::poll}, val: Value(<ZST>) }
+    }
+
+    bb7: {
+        StorageDead(_13);                // scope 2 at $DIR/async_await.rs:+1:13: +1:14
+        StorageDead(_10);                // scope 2 at $DIR/async_await.rs:+1:13: +1:14
+        _16 = discriminant(_9);          // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        switchInt(move _16) -> [0: bb10, 1: bb8, otherwise: bb9]; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+    }
+
+    bb8: {
+        _8 = const ();                   // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        StorageDead(_14);                // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        StorageDead(_12);                // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        StorageDead(_9);                 // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        StorageDead(_8);                 // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        StorageLive(_19);                // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        StorageLive(_20);                // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        _20 = ();                        // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        Deinit(_0);                      // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        discriminant(_0) = 1;            // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))) = 3; // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        return;                          // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+    }
+
+    bb9: {
+        unreachable;                     // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+    }
+
+    bb10: {
+        StorageLive(_17);                // scope 1 at $DIR/async_await.rs:+1:5: +1:14
+        _17 = ((_9 as Ready).0: ());     // scope 1 at $DIR/async_await.rs:+1:5: +1:14
+        _3 = _17;                        // scope 3 at $DIR/async_await.rs:+1:5: +1:14
+        StorageDead(_17);                // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        StorageDead(_14);                // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        StorageDead(_12);                // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        StorageDead(_9);                 // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        StorageDead(_8);                 // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        goto -> bb12;                    // scope 0 at $DIR/async_await.rs:+1:13: +1:14
+    }
+
+    bb11: {
+        StorageDead(_20);                // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        _38 = move _19;                  // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        StorageDead(_19);                // scope 1 at $DIR/async_await.rs:+1:13: +1:14
+        _7 = const ();                   // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+        goto -> bb4;                     // scope 1 at $DIR/async_await.rs:+1:8: +1:14
+    }
+
+    bb12: {
+        nop;                             // scope 0 at $DIR/async_await.rs:+1:13: +1:14
+        goto -> bb13;                    // scope 0 at $DIR/async_await.rs:+1:14: +1:15
+    }
+
+    bb13: {
+        StorageDead(_4);                 // scope 0 at $DIR/async_await.rs:+1:14: +1:15
+        StorageDead(_3);                 // scope 0 at $DIR/async_await.rs:+1:14: +1:15
+        StorageLive(_21);                // scope 0 at $DIR/async_await.rs:+2:8: +2:14
+        StorageLive(_22);                // scope 0 at $DIR/async_await.rs:+2:5: +2:8
+        _22 = a() -> bb14;               // scope 0 at $DIR/async_await.rs:+2:5: +2:8
+                                         // mir::Constant
+                                         // + span: $DIR/async_await.rs:16:5: 16:6
+                                         // + literal: Const { ty: fn() -> impl Future<Output = ()> {a}, val: Value(<ZST>) }
+    }
+
+    bb14: {
+        _21 = <impl Future<Output = ()> as IntoFuture>::into_future(move _22) -> bb15; // scope 0 at $DIR/async_await.rs:+2:8: +2:14
+                                         // mir::Constant
+                                         // + span: $DIR/async_await.rs:16:8: 16:14
+                                         // + literal: Const { ty: fn(impl Future<Output = ()>) -> <impl Future<Output = ()> as IntoFuture>::IntoFuture {<impl Future<Output = ()> as IntoFuture>::into_future}, val: Value(<ZST>) }
+    }
+
+    bb15: {
+        StorageDead(_22);                // scope 0 at $DIR/async_await.rs:+2:13: +2:14
+        nop;                             // scope 0 at $DIR/async_await.rs:+2:8: +2:14
+        (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#4).0: impl std::future::Future<Output = ()>) = move _21; // scope 0 at $DIR/async_await.rs:+2:8: +2:14
+        goto -> bb16;                    // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+    }
+
+    bb16: {
+        StorageLive(_24);                // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        StorageLive(_25);                // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        StorageLive(_26);                // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+        StorageLive(_27);                // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+        StorageLive(_28);                // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+        _28 = &mut (((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2])) as variant#4).0: impl std::future::Future<Output = ()>); // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+        _27 = &mut (*_28);               // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+        _26 = Pin::<&mut impl Future<Output = ()>>::new_unchecked(move _27) -> bb17; // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+                                         // mir::Constant
+                                         // + span: $DIR/async_await.rs:16:8: 16:14
+                                         // + literal: Const { ty: unsafe fn(&mut impl Future<Output = ()>) -> Pin<&mut impl Future<Output = ()>> {Pin::<&mut impl Future<Output = ()>>::new_unchecked}, val: Value(<ZST>) }
+    }
+
+    bb17: {
+        StorageDead(_27);                // scope 5 at $DIR/async_await.rs:+2:13: +2:14
+        StorageLive(_29);                // scope 5 at $DIR/async_await.rs:+2:5: +2:14
+        StorageLive(_30);                // scope 5 at $DIR/async_await.rs:+2:5: +2:14
+        StorageLive(_31);                // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+        _31 = _38;                       // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+        _30 = move _31;                  // scope 5 at $DIR/async_await.rs:+2:5: +2:14
+        goto -> bb18;                    // scope 5 at $DIR/async_await.rs:+2:5: +2:14
+    }
+
+    bb18: {
+        _29 = &mut (*_30);               // scope 5 at $DIR/async_await.rs:+2:5: +2:14
+        StorageDead(_31);                // scope 5 at $DIR/async_await.rs:+2:13: +2:14
+        _25 = <impl Future<Output = ()> as Future>::poll(move _26, move _29) -> bb19; // scope 5 at $DIR/async_await.rs:+2:8: +2:14
+                                         // mir::Constant
+                                         // + span: $DIR/async_await.rs:16:8: 16:14
+                                         // + literal: Const { ty: for<'a, 'b, 'c> fn(Pin<&'a mut impl Future<Output = ()>>, &'b mut Context<'c>) -> Poll<<impl Future<Output = ()> as Future>::Output> {<impl Future<Output = ()> as Future>::poll}, val: Value(<ZST>) }
+    }
+
+    bb19: {
+        StorageDead(_29);                // scope 5 at $DIR/async_await.rs:+2:13: +2:14
+        StorageDead(_26);                // scope 5 at $DIR/async_await.rs:+2:13: +2:14
+        _32 = discriminant(_25);         // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        switchInt(move _32) -> [0: bb22, 1: bb20, otherwise: bb21]; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+    }
+
+    bb20: {
+        _24 = const ();                  // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        StorageDead(_30);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        StorageDead(_28);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        StorageDead(_25);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        StorageDead(_24);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        StorageLive(_35);                // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        StorageLive(_36);                // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        _36 = ();                        // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        Deinit(_0);                      // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        discriminant(_0) = 1;            // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))) = 4; // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        return;                          // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+    }
+
+    bb21: {
+        unreachable;                     // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+    }
+
+    bb22: {
+        StorageLive(_33);                // scope 4 at $DIR/async_await.rs:+2:5: +2:14
+        _33 = ((_25 as Ready).0: ());    // scope 4 at $DIR/async_await.rs:+2:5: +2:14
+        _37 = _33;                       // scope 6 at $DIR/async_await.rs:+2:5: +2:14
+        StorageDead(_33);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        StorageDead(_30);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        StorageDead(_28);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        StorageDead(_25);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        StorageDead(_24);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        goto -> bb24;                    // scope 0 at $DIR/async_await.rs:+2:13: +2:14
+    }
+
+    bb23: {
+        StorageDead(_36);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        _38 = move _35;                  // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        StorageDead(_35);                // scope 4 at $DIR/async_await.rs:+2:13: +2:14
+        _7 = const ();                   // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+        goto -> bb16;                    // scope 4 at $DIR/async_await.rs:+2:8: +2:14
+    }
+
+    bb24: {
+        nop;                             // scope 0 at $DIR/async_await.rs:+2:13: +2:14
+        goto -> bb25;                    // scope 0 at $DIR/async_await.rs:+3:1: +3:2
+    }
+
+    bb25: {
+        StorageDead(_21);                // scope 0 at $DIR/async_await.rs:+3:1: +3:2
+        goto -> bb26;                    // scope 0 at $DIR/async_await.rs:+3:1: +3:2
+    }
+
+    bb26: {
+        Deinit(_0);                      // scope 0 at $DIR/async_await.rs:+3:2: +3:2
+        ((_0 as Ready).0: ()) = move _37; // scope 0 at $DIR/async_await.rs:+3:2: +3:2
+        discriminant(_0) = 0;            // scope 0 at $DIR/async_await.rs:+3:2: +3:2
+        discriminant((*(_1.0: &mut [async fn body@$DIR/async_await.rs:14:18: 17:2]))) = 1; // scope 0 at $DIR/async_await.rs:+3:2: +3:2
+        return;                          // scope 0 at $DIR/async_await.rs:+3:2: +3:2
+    }
+
+    bb27: {
+        StorageLive(_3);                 // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        StorageLive(_4);                 // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        StorageLive(_19);                // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        StorageLive(_20);                // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        _19 = move _2;                   // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        goto -> bb11;                    // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    }
+
+    bb28: {
+        StorageLive(_21);                // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        StorageLive(_35);                // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        StorageLive(_36);                // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        _35 = move _2;                   // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+        goto -> bb23;                    // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    }
+
+    bb29: {
+        assert(const false, "`async fn` resumed after completion") -> bb29; // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    }
+
+    bb30: {
+        unreachable;                     // scope 0 at $DIR/async_await.rs:+0:18: +3:2
+    }
+}
diff --git a/tests/mir-opt/building/async_await.rs b/tests/mir-opt/building/async_await.rs
new file mode 100644
index 00000000000..0b991e3b8f8
--- /dev/null
+++ b/tests/mir-opt/building/async_await.rs
@@ -0,0 +1,17 @@
+// This test makes sure that the generator MIR pass eliminates all calls to
+// `get_context`, and that the MIR argument type for an async fn and all locals
+// related to `yield` are `&mut Context`, and its return type is `Poll`.
+
+// edition:2018
+// compile-flags: -C panic=abort
+
+#![crate_type = "lib"]
+
+// EMIT_MIR async_await.a-{closure#0}.generator_resume.0.mir
+async fn a() {}
+
+// EMIT_MIR async_await.b-{closure#0}.generator_resume.0.mir
+pub async fn b() {
+    a().await;
+    a().await
+}
diff --git a/tests/mir-opt/building/custom/simple_assign.rs b/tests/mir-opt/building/custom/simple_assign.rs
index ec6dbe1d052..db041aab239 100644
--- a/tests/mir-opt/building/custom/simple_assign.rs
+++ b/tests/mir-opt/building/custom/simple_assign.rs
@@ -11,12 +11,14 @@ pub fn simple(x: i32) -> i32 {
         let temp2: _;
 
         {
+            StorageLive(temp1);
             temp1 = x;
             Goto(exit)
         }
 
         exit = {
             temp2 = Move(temp1);
+            StorageDead(temp1);
             RET = temp2;
             Return()
         }
diff --git a/tests/mir-opt/building/custom/simple_assign.simple.built.after.mir b/tests/mir-opt/building/custom/simple_assign.simple.built.after.mir
index d7560fde69c..743016708c5 100644
--- a/tests/mir-opt/building/custom/simple_assign.simple.built.after.mir
+++ b/tests/mir-opt/building/custom/simple_assign.simple.built.after.mir
@@ -6,13 +6,15 @@ fn simple(_1: i32) -> i32 {
     let mut _3: i32;                     // in scope 0 at $SRC_DIR/core/src/intrinsics/mir.rs:LL:COL
 
     bb0: {
-        _2 = _1;                         // scope 0 at $DIR/simple_assign.rs:+6:13: +6:22
-        goto -> bb1;                     // scope 0 at $DIR/simple_assign.rs:+7:13: +7:23
+        StorageLive(_2);                 // scope 0 at $DIR/simple_assign.rs:+6:13: +6:31
+        _2 = _1;                         // scope 0 at $DIR/simple_assign.rs:+7:13: +7:22
+        goto -> bb1;                     // scope 0 at $DIR/simple_assign.rs:+8:13: +8:23
     }
 
     bb1: {
-        _3 = move _2;                    // scope 0 at $DIR/simple_assign.rs:+11:13: +11:32
-        _0 = _3;                         // scope 0 at $DIR/simple_assign.rs:+12:13: +12:24
-        return;                          // scope 0 at $DIR/simple_assign.rs:+13:13: +13:21
+        _3 = move _2;                    // scope 0 at $DIR/simple_assign.rs:+12:13: +12:32
+        StorageDead(_2);                 // scope 0 at $DIR/simple_assign.rs:+13:13: +13:31
+        _0 = _3;                         // scope 0 at $DIR/simple_assign.rs:+14:13: +14:24
+        return;                          // scope 0 at $DIR/simple_assign.rs:+15:13: +15:21
     }
 }
diff --git a/tests/mir-opt/inline/inline_into_box_place.main.Inline.diff b/tests/mir-opt/inline/inline_into_box_place.main.Inline.diff
index 2a4dc9e3e80..a28da146e37 100644
--- a/tests/mir-opt/inline/inline_into_box_place.main.Inline.diff
+++ b/tests/mir-opt/inline/inline_into_box_place.main.Inline.diff
@@ -11,13 +11,14 @@
       let mut _6: ();                      // in scope 0 at $DIR/inline_into_box_place.rs:+1:42: +1:43
       let mut _7: *const std::vec::Vec<u32>; // in scope 0 at $DIR/inline_into_box_place.rs:+1:29: +1:43
 +     let mut _8: &mut std::vec::Vec<u32>; // in scope 0 at $DIR/inline_into_box_place.rs:+1:33: +1:43
++     let mut _9: std::vec::Vec<u32>;      // in scope 0 at $DIR/inline_into_box_place.rs:+1:33: +1:43
       scope 1 {
           debug _x => _1;                  // in scope 1 at $DIR/inline_into_box_place.rs:+1:9: +1:11
       }
       scope 2 {
       }
 +     scope 3 (inlined Vec::<u32>::new) {  // at $DIR/inline_into_box_place.rs:8:33: 8:43
-+         let mut _9: alloc::raw_vec::RawVec<u32>; // in scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
++         let mut _10: alloc::raw_vec::RawVec<u32>; // in scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
 +     }
   
       bb0: {
@@ -37,8 +38,9 @@
 -         (*_7) = Vec::<u32>::new() -> [return: bb2, unwind: bb5]; // scope 0 at $DIR/inline_into_box_place.rs:+1:33: +1:43
 +         StorageLive(_8);                 // scope 0 at $DIR/inline_into_box_place.rs:+1:33: +1:43
 +         _8 = &mut (*_7);                 // scope 0 at $DIR/inline_into_box_place.rs:+1:33: +1:43
-+         StorageLive(_9);                 // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+         _9 = const _;                    // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
++         StorageLive(_9);                 // scope 0 at $DIR/inline_into_box_place.rs:+1:33: +1:43
++         StorageLive(_10);                // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
++         _10 = const _;                   // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
                                            // mir::Constant
 -                                          // + span: $DIR/inline_into_box_place.rs:8:33: 8:41
 -                                          // + user_ty: UserType(1)
@@ -49,10 +51,12 @@
 +                                          // + span: $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
 +                                          // + user_ty: UserType(0)
 +                                          // + literal: Const { ty: alloc::raw_vec::RawVec<u32>, val: Unevaluated(alloc::raw_vec::RawVec::<T>::NEW, [u32], None) }
-+         Deinit((*_8));                   // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+         ((*_8).0: alloc::raw_vec::RawVec<u32>) = move _9; // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+         ((*_8).1: usize) = const 0_usize; // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
-+         StorageDead(_9);                 // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
++         Deinit(_9);                      // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
++         (_9.0: alloc::raw_vec::RawVec<u32>) = move _10; // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
++         (_9.1: usize) = const 0_usize;   // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
++         StorageDead(_10);                // scope 3 at $SRC_DIR/alloc/src/vec/mod.rs:LL:COL
++         (*_8) = move _9;                 // scope 0 at $DIR/inline_into_box_place.rs:+1:33: +1:43
++         StorageDead(_9);                 // scope 0 at $DIR/inline_into_box_place.rs:+1:33: +1:43
 +         StorageDead(_8);                 // scope 0 at $DIR/inline_into_box_place.rs:+1:33: +1:43
           _1 = move _5;                    // scope 0 at $DIR/inline_into_box_place.rs:+1:29: +1:43
           StorageDead(_5);                 // scope 0 at $DIR/inline_into_box_place.rs:+1:42: +1:43
diff --git a/tests/mir-opt/inline/issue_106141.outer.Inline.diff b/tests/mir-opt/inline/issue_106141.outer.Inline.diff
new file mode 100644
index 00000000000..97361fa5f4c
--- /dev/null
+++ b/tests/mir-opt/inline/issue_106141.outer.Inline.diff
@@ -0,0 +1,55 @@
+- // MIR for `outer` before Inline
++ // MIR for `outer` after Inline
+  
+  fn outer() -> usize {
+      let mut _0: usize;                   // return place in scope 0 at $DIR/issue_106141.rs:+0:19: +0:24
++     scope 1 (inlined inner) {            // at $DIR/issue_106141.rs:2:5: 2:12
++         let mut _1: bool;                // in scope 1 at $DIR/issue_106141.rs:13:8: 13:21
++         let mut _2: bool;                // in scope 1 at $DIR/issue_106141.rs:13:8: 13:21
++         let mut _3: &[bool; 1];          // in scope 1 at $DIR/issue_106141.rs:11:18: 11:25
++         scope 2 {
++             debug buffer => _3;          // in scope 2 at $DIR/issue_106141.rs:11:9: 11:15
++             scope 3 {
++                 debug index => _0;       // in scope 3 at $DIR/issue_106141.rs:12:9: 12:14
++             }
++         }
++     }
+  
+      bb0: {
+-         _0 = inner() -> bb1;             // scope 0 at $DIR/issue_106141.rs:+1:5: +1:12
++         StorageLive(_3);                 // scope 0 at $DIR/issue_106141.rs:+1:5: +1:12
++         _3 = const _;                    // scope 1 at $DIR/issue_106141.rs:11:18: 11:25
+                                           // mir::Constant
+-                                          // + span: $DIR/issue_106141.rs:2:5: 2:10
+-                                          // + literal: Const { ty: fn() -> usize {inner}, val: Value(<ZST>) }
++                                          // + span: $DIR/issue_106141.rs:11:18: 11:25
++                                          // + literal: Const { ty: &[bool; 1], val: Unevaluated(inner, [], Some(promoted[0])) }
++         _0 = index() -> bb1;             // scope 2 at $DIR/issue_106141.rs:12:17: 12:24
++                                          // mir::Constant
++                                          // + span: $DIR/issue_106141.rs:12:17: 12:22
++                                          // + literal: Const { ty: fn() -> usize {index}, val: Value(<ZST>) }
+      }
+  
+      bb1: {
++         StorageLive(_1);                 // scope 3 at $DIR/issue_106141.rs:13:8: 13:21
++         _2 = Lt(_0, const 1_usize);      // scope 3 at $DIR/issue_106141.rs:13:8: 13:21
++         assert(move _2, "index out of bounds: the length is {} but the index is {}", const 1_usize, _0) -> bb2; // scope 3 at $DIR/issue_106141.rs:13:8: 13:21
++     }
++ 
++     bb2: {
++         _1 = (*_3)[_0];                  // scope 3 at $DIR/issue_106141.rs:13:8: 13:21
++         switchInt(move _1) -> [0: bb3, otherwise: bb4]; // scope 3 at $DIR/issue_106141.rs:13:8: 13:21
++     }
++ 
++     bb3: {
++         _0 = const 0_usize;              // scope 3 at $DIR/issue_106141.rs:16:9: 16:10
++         goto -> bb4;                     // scope 3 at $DIR/issue_106141.rs:13:5: 17:6
++     }
++ 
++     bb4: {
++         StorageDead(_1);                 // scope 3 at $DIR/issue_106141.rs:17:5: 17:6
++         StorageDead(_3);                 // scope 0 at $DIR/issue_106141.rs:+1:5: +1:12
+          return;                          // scope 0 at $DIR/issue_106141.rs:+2:2: +2:2
+      }
+  }
+  
diff --git a/tests/mir-opt/inline/issue_106141.rs b/tests/mir-opt/inline/issue_106141.rs
new file mode 100644
index 00000000000..c8288b7f341
--- /dev/null
+++ b/tests/mir-opt/inline/issue_106141.rs
@@ -0,0 +1,24 @@
+pub fn outer() -> usize {
+    inner()
+}
+
+fn index() -> usize {
+    loop {}
+}
+
+#[inline]
+fn inner() -> usize {
+    let buffer = &[true];
+    let index = index();
+    if buffer[index] {
+        index
+    } else {
+        0
+    }
+}
+
+fn main() {
+    outer();
+}
+
+// EMIT_MIR issue_106141.outer.Inline.diff
diff --git a/tests/mir-opt/nll/region_subtyping_basic.main.nll.0.32bit.mir b/tests/mir-opt/nll/region_subtyping_basic.main.nll.0.32bit.mir
index 8e6564a38b0..798e45df8ca 100644
--- a/tests/mir-opt/nll/region_subtyping_basic.main.nll.0.32bit.mir
+++ b/tests/mir-opt/nll/region_subtyping_basic.main.nll.0.32bit.mir
@@ -22,7 +22,7 @@
 |
 fn main() -> () {
     let mut _0: ();                      // return place in scope 0 at $DIR/region_subtyping_basic.rs:+0:11: +0:11
-    let mut _1: [usize; Const { ty: usize, kind: Value(Leaf(0x00000003)) }]; // in scope 0 at $DIR/region_subtyping_basic.rs:+1:9: +1:14
+    let mut _1: [usize; Const(Value(Leaf(0x00000003)): usize)]; // in scope 0 at $DIR/region_subtyping_basic.rs:+1:9: +1:14
     let _3: usize;                       // in scope 0 at $DIR/region_subtyping_basic.rs:+2:16: +2:17
     let mut _4: usize;                   // in scope 0 at $DIR/region_subtyping_basic.rs:+2:14: +2:18
     let mut _5: bool;                    // in scope 0 at $DIR/region_subtyping_basic.rs:+2:14: +2:18
diff --git a/tests/mir-opt/nll/region_subtyping_basic.main.nll.0.64bit.mir b/tests/mir-opt/nll/region_subtyping_basic.main.nll.0.64bit.mir
index 74d44c6741a..4767bfc76ed 100644
--- a/tests/mir-opt/nll/region_subtyping_basic.main.nll.0.64bit.mir
+++ b/tests/mir-opt/nll/region_subtyping_basic.main.nll.0.64bit.mir
@@ -22,7 +22,7 @@
 |
 fn main() -> () {
     let mut _0: ();                      // return place in scope 0 at $DIR/region_subtyping_basic.rs:+0:11: +0:11
-    let mut _1: [usize; Const { ty: usize, kind: Value(Leaf(0x0000000000000003)) }]; // in scope 0 at $DIR/region_subtyping_basic.rs:+1:9: +1:14
+    let mut _1: [usize; Const(Value(Leaf(0x0000000000000003)): usize)]; // in scope 0 at $DIR/region_subtyping_basic.rs:+1:9: +1:14
     let _3: usize;                       // in scope 0 at $DIR/region_subtyping_basic.rs:+2:16: +2:17
     let mut _4: usize;                   // in scope 0 at $DIR/region_subtyping_basic.rs:+2:14: +2:18
     let mut _5: bool;                    // in scope 0 at $DIR/region_subtyping_basic.rs:+2:14: +2:18
diff --git a/tests/run-make-fulldeps/issue-19371/foo.rs b/tests/run-make-fulldeps/issue-19371/foo.rs
index 7e1b6aeb315..5bb38fc02af 100644
--- a/tests/run-make-fulldeps/issue-19371/foo.rs
+++ b/tests/run-make-fulldeps/issue-19371/foo.rs
@@ -1,12 +1,12 @@
 #![feature(rustc_private)]
 
-extern crate rustc_interface;
 extern crate rustc_driver;
+extern crate rustc_interface;
 extern crate rustc_session;
 extern crate rustc_span;
 
-use rustc_session::config::{Input, Options, OutputType, OutputTypes};
 use rustc_interface::interface;
+use rustc_session::config::{Input, Options, OutputType, OutputTypes};
 use rustc_span::source_map::FileName;
 
 use std::path::PathBuf;
@@ -50,7 +50,6 @@ fn compile(code: String, output: PathBuf, sysroot: PathBuf) {
         crate_cfg: Default::default(),
         crate_check_cfg: Default::default(),
         input,
-        input_path: None,
         output_file: Some(output),
         output_dir: None,
         file_loader: None,
@@ -64,9 +63,7 @@ fn compile(code: String, output: PathBuf, sysroot: PathBuf) {
 
     interface::run_compiler(config, |compiler| {
         // This runs all the passes prior to linking, too.
-        let linker = compiler.enter(|queries| {
-            queries.linker()
-        });
+        let linker = compiler.enter(|queries| queries.linker());
         if let Ok(linker) = linker {
             linker.link();
         }
diff --git a/tests/rustdoc-gui/basic-code.goml b/tests/rustdoc-gui/basic-code.goml
index 108cf8abcb5..971c2f9480e 100644
--- a/tests/rustdoc-gui/basic-code.goml
+++ b/tests/rustdoc-gui/basic-code.goml
@@ -1,3 +1,5 @@
+// Small test to ensure the "src-line-numbers" element is only present once on
+// the page.
 goto: "file://" + |DOC_PATH| + "/test_docs/index.html"
 click: ".srclink"
 wait-for: ".src-line-numbers"
diff --git a/tests/rustdoc-gui/code-tags.goml b/tests/rustdoc-gui/code-tags.goml
index 94c1a6525aa..8561f537f3d 100644
--- a/tests/rustdoc-gui/code-tags.goml
+++ b/tests/rustdoc-gui/code-tags.goml
@@ -9,16 +9,16 @@ size: (1080, 600)
 // Check that their content is inside <pre><code>
 assert-count: (".example-wrap pre > code", 4)
 // Check that function signature is inside <pre><code>
-assert: "pre.rust.fn > code"
+assert: ".item-decl pre.rust > code"
 
 goto: "file://" + |DOC_PATH| + "/test_docs/struct.Foo.html"
-assert: "pre.rust.struct > code"
+assert: ".item-decl pre.rust > code"
 
 goto: "file://" + |DOC_PATH| + "/test_docs/enum.AnEnum.html"
-assert: "pre.rust.enum > code"
+assert: ".item-decl pre.rust > code"
 
 goto: "file://" + |DOC_PATH| + "/test_docs/trait.AnotherOne.html"
-assert: "pre.rust.trait > code"
+assert: ".item-decl pre.rust > code"
 
 goto: "file://" + |DOC_PATH| + "/test_docs/type.SomeType.html"
-assert: "pre.rust.typedef > code"
+assert: ".item-decl pre.rust > code"
diff --git a/tests/rustdoc-gui/font-weight.goml b/tests/rustdoc-gui/font-weight.goml
index 8ba005b0c35..fafb1563178 100644
--- a/tests/rustdoc-gui/font-weight.goml
+++ b/tests/rustdoc-gui/font-weight.goml
@@ -20,7 +20,7 @@ goto: "file://" + |DOC_PATH| + "/lib2/trait.Trait.html"
 // This is a complex selector, so here's how it works:
 //
 // * //*[@class='item-decl'] — selects element of any tag with classes docblock and item-decl
-// * /pre[@class='rust trait'] — selects immediate child with tag pre and classes rust and trait
+// * /pre[@class='rust'] — selects immediate child with tag pre and class rust
 // * /code — selects immediate child with tag code
 // * /a[@class='constant'] — selects immediate child with tag a and class constant
 // * //text() — selects child that is text node
@@ -29,11 +29,11 @@ goto: "file://" + |DOC_PATH| + "/lib2/trait.Trait.html"
 // This uses '/parent::*' as a proxy for the style of the text node.
 // We can't just select the '<a>' because intermediate tags could be added.
 assert-count: (
-    "//*[@class='item-decl']/pre[@class='rust trait']/code/a[@class='constant']//text()/parent::*",
+    "//*[@class='item-decl']/pre[@class='rust']/code/a[@class='constant']//text()/parent::*",
     1,
 )
 assert-css: (
-    "//*[@class='item-decl']/pre[@class='rust trait']/code/a[@class='constant']//text()/parent::*",
+    "//*[@class='item-decl']/pre[@class='rust']/code/a[@class='constant']//text()/parent::*",
     {"font-weight": "400"},
 )
 
diff --git a/tests/rustdoc-gui/list_code_block.goml b/tests/rustdoc-gui/list_code_block.goml
index 3423a449de4..c527cfbfcbc 100644
--- a/tests/rustdoc-gui/list_code_block.goml
+++ b/tests/rustdoc-gui/list_code_block.goml
@@ -1,4 +1,4 @@
 // This test checks that code blocks in list are supported.
 goto: "file://" + |DOC_PATH| + "/test_docs/index.html"
 goto: "./fn.check_list_code_block.html"
-assert: ("pre.rust.fn")
+assert: (".item-decl pre.rust")
diff --git a/tests/rustdoc-gui/scrape-examples-color.goml b/tests/rustdoc-gui/scrape-examples-color.goml
index 40f31b2771b..67c58826efc 100644
--- a/tests/rustdoc-gui/scrape-examples-color.goml
+++ b/tests/rustdoc-gui/scrape-examples-color.goml
@@ -58,3 +58,39 @@ call-function: ("check-colors", {
     "help_hover_border": "rgb(0, 0, 0)",
     "help_hover_color": "rgb(0, 0, 0)",
 })
+
+// Now testing the top and bottom background in case there is only one scraped examples.
+goto: "file://" + |DOC_PATH| + "/scrape_examples/fn.test.html"
+
+define-function: (
+    "check-background",
+    (theme, background_color_start, background_color_end),
+    block {
+        local-storage: { "rustdoc-theme": |theme|, "rustdoc-use-system-theme": "false", }
+        reload:
+        assert-css: (".scraped-example:not(.expanded) .code-wrapper::before", {
+            "background-image": "linear-gradient(" + |background_color_start| + ", " +
+                |background_color_end| + ")",
+        })
+        assert-css: (".scraped-example:not(.expanded) .code-wrapper::after", {
+            "background-image": "linear-gradient(to top, " + |background_color_start| + ", " +
+                |background_color_end| + ")",
+        })
+    },
+)
+
+call-function: ("check-background", {
+    "theme": "ayu",
+    "background_color_start": "rgb(15, 20, 25)",
+    "background_color_end": "rgba(15, 20, 25, 0)",
+})
+call-function: ("check-background", {
+    "theme": "dark",
+    "background_color_start": "rgb(53, 53, 53)",
+    "background_color_end": "rgba(53, 53, 53, 0)",
+})
+call-function: ("check-background", {
+    "theme": "light",
+    "background_color_start": "rgb(255, 255, 255)",
+    "background_color_end": "rgba(255, 255, 255, 0)",
+})
diff --git a/tests/rustdoc-gui/settings.goml b/tests/rustdoc-gui/settings.goml
index f236dc3e0fe..419cc5ebac3 100644
--- a/tests/rustdoc-gui/settings.goml
+++ b/tests/rustdoc-gui/settings.goml
@@ -8,6 +8,10 @@ assert-false: "#settings"
 click: "#settings-menu"
 wait-for: "#settings"
 assert-css: ("#settings", {"display": "block"})
+
+// Store the line margin to compare with the settings.html later.
+store-css: (setting_line_margin, ".setting-line", "margin")
+
 // Let's close it by clicking on the same button.
 click: "#settings-menu"
 wait-for-css: ("#settings", {"display": "none"})
@@ -105,6 +109,33 @@ assert-css: (
         "box-shadow": "rgb(33, 150, 243) 0px 0px 1px 1px",
     },
 )
+// Now we check the setting-name for radio buttons is on a different line than the label.
+compare-elements-position-near: (
+    "#theme .setting-name",
+    "#theme .choices",
+    {"x": 1}
+)
+compare-elements-position-near-false: (
+    "#theme .setting-name",
+    "#theme .choices",
+    {"y": 1}
+)
+// Now we check that the label positions are all on the same line.
+compare-elements-position-near: (
+    "#theme .choices #theme-light",
+    "#theme .choices #theme-dark",
+    {"y": 1}
+)
+compare-elements-position-near: (
+    "#theme .choices #theme-dark",
+    "#theme .choices #theme-ayu",
+    {"y": 1}
+)
+compare-elements-position-near: (
+    "#theme .choices #theme-ayu",
+    "#theme .choices #theme-system-preference",
+    {"y": 1}
+)
 
 // First we check the "default" display for toggles.
 assert-css: (
@@ -176,6 +207,25 @@ press-key: "?"
 wait-for-css: ("#help-button .popover", {"display": "block"})
 assert-css: ("#settings-menu .popover", {"display": "none"})
 
+// Now switch back to the settings popover, and make sure the keyboard
+// shortcut works when a check box is selected.
+click: "#settings-menu > a"
+wait-for-css: ("#settings-menu .popover", {"display": "block"})
+focus: "#auto-hide-large-items"
+press-key: "?"
+wait-for-css: ("#settings-menu .popover", {"display": "none"})
+wait-for-css: ("#help-button .popover", {"display": "block"})
+
+// Now switch back to the settings popover, and make sure the keyboard
+// shortcut works when a check box is selected.
+click: "#settings-menu > a"
+wait-for-css: ("#settings-menu .popover", {"display": "block"})
+wait-for-css: ("#help-button .popover", {"display": "none"})
+focus: "#theme-system-preference"
+press-key: "?"
+wait-for-css: ("#settings-menu .popover", {"display": "none"})
+wait-for-css: ("#help-button .popover", {"display": "block"})
+
 // Now we go to the settings page to check that the CSS is loaded as expected.
 goto: "file://" + |DOC_PATH| + "/settings.html"
 wait-for: "#settings"
@@ -184,6 +234,9 @@ assert-css: (".setting-line", {"position": "relative"})
 assert-attribute-false: ("#settings", {"class": "popover"}, CONTAINS)
 compare-elements-position: (".sub form", "#settings", ("x"))
 
+// Check that setting-line has the same margin in this mode as in the popover.
+assert-css: (".setting-line", {"margin": |setting_line_margin|})
+
 // We now check the display with JS disabled.
 assert-false: "noscript section"
 javascript: false
diff --git a/tests/rustdoc-js-std/macro-print.js b/tests/rustdoc-js-std/macro-print.js
index 858046e72e9..1b4c7b40570 100644
--- a/tests/rustdoc-js-std/macro-print.js
+++ b/tests/rustdoc-js-std/macro-print.js
@@ -3,8 +3,8 @@ const QUERY = 'macro:print';
 const EXPECTED = {
     'others': [
         { 'path': 'std', 'name': 'print' },
-        { 'path': 'std', 'name': 'eprint' },
         { 'path': 'std', 'name': 'println' },
+        { 'path': 'std', 'name': 'eprint' },
         { 'path': 'std', 'name': 'eprintln' },
     ],
 };
diff --git a/tests/rustdoc-js-std/typed-query.js b/tests/rustdoc-js-std/typed-query.js
index 25efbad2695..fd5c5489d79 100644
--- a/tests/rustdoc-js-std/typed-query.js
+++ b/tests/rustdoc-js-std/typed-query.js
@@ -6,8 +6,8 @@ const FILTER_CRATE = 'std';
 const EXPECTED = {
     'others': [
         { 'path': 'std', 'name': 'print' },
-        { 'path': 'std', 'name': 'eprint' },
         { 'path': 'std', 'name': 'println' },
+        { 'path': 'std', 'name': 'eprint' },
         { 'path': 'std', 'name': 'eprintln' },
         { 'path': 'std::pin', 'name': 'pin' },
         { 'path': 'std::future', 'name': 'join' },
diff --git a/tests/rustdoc-js-std/vec-new.js b/tests/rustdoc-js-std/vec-new.js
index cd0e8e7b4a9..fc44a566af2 100644
--- a/tests/rustdoc-js-std/vec-new.js
+++ b/tests/rustdoc-js-std/vec-new.js
@@ -3,7 +3,8 @@ const QUERY = 'Vec::new';
 const EXPECTED = {
     'others': [
         { 'path': 'std::vec::Vec', 'name': 'new' },
-        { 'path': 'std::vec::Vec', 'name': 'ne' },
-        { 'path': 'alloc::vec::Vec', 'name': 'ne' },
+        { 'path': 'alloc::vec::Vec', 'name': 'new' },
+        { 'path': 'std::vec::Vec', 'name': 'new_in' },
+        { 'path': 'alloc::vec::Vec', 'name': 'new_in' },
     ],
 };
diff --git a/tests/rustdoc-js/search-short-types.js b/tests/rustdoc-js/search-short-types.js
index d14672af71f..3b2f15a40bf 100644
--- a/tests/rustdoc-js/search-short-types.js
+++ b/tests/rustdoc-js/search-short-types.js
@@ -4,7 +4,6 @@ const EXPECTED = {
     'others': [
         { 'path': 'search_short_types', 'name': 'P' },
         { 'path': 'search_short_types::VeryLongTypeName', 'name': 'p' },
-        { 'path': 'search_short_types', 'name': 'Ap' },
-        { 'path': 'search_short_types::VeryLongTypeName', 'name': 'ap' },
+        { 'path': 'search_short_types', 'name': 'Pa' },
     ],
 };
diff --git a/tests/rustdoc-ui/infinite-recursive-type-impl-trait-return.rs b/tests/rustdoc-ui/infinite-recursive-type-impl-trait-return.rs
index 939da186fbc..4b1e04234c8 100644
--- a/tests/rustdoc-ui/infinite-recursive-type-impl-trait-return.rs
+++ b/tests/rustdoc-ui/infinite-recursive-type-impl-trait-return.rs
@@ -1,10 +1,12 @@
+// check-pass
 // normalize-stderr-test: "`.*`" -> "`DEF_ID`"
 // normalize-stdout-test: "`.*`" -> "`DEF_ID`"
 // edition:2018
 
 pub async fn f() -> impl std::fmt::Debug {
+    // rustdoc doesn't care that this is infinitely sized
     #[derive(Debug)]
-    enum E { //~ ERROR
+    enum E {
         This(E),
         Unit,
     }
diff --git a/tests/rustdoc-ui/infinite-recursive-type-impl-trait-return.stderr b/tests/rustdoc-ui/infinite-recursive-type-impl-trait-return.stderr
deleted file mode 100644
index aff7402bc91..00000000000
--- a/tests/rustdoc-ui/infinite-recursive-type-impl-trait-return.stderr
+++ /dev/null
@@ -1,16 +0,0 @@
-error[E0072]: recursive type `DEF_ID` has infinite size
-  --> $DIR/infinite-recursive-type-impl-trait-return.rs:7:5
-   |
-LL |     enum E {
-   |     ^^^^^^
-LL |         This(E),
-   |              - recursive without indirection
-   |
-help: insert some indirection (e.g., a `DEF_ID`) to break the cycle
-   |
-LL |         This(Box<E>),
-   |              ++++ +
-
-error: aborting due to previous error
-
-For more information about this error, try `DEF_ID`.
diff --git a/tests/rustdoc-ui/infinite-recursive-type-impl-trait.rs b/tests/rustdoc-ui/infinite-recursive-type-impl-trait.rs
index ac517257498..ac79582fb3f 100644
--- a/tests/rustdoc-ui/infinite-recursive-type-impl-trait.rs
+++ b/tests/rustdoc-ui/infinite-recursive-type-impl-trait.rs
@@ -1,5 +1,8 @@
+// check-pass
+
 fn f() -> impl Sized {
-    enum E { //~ ERROR
+    // rustdoc doesn't care that this is infinitely sized
+    enum E {
         V(E),
     }
     unimplemented!()
diff --git a/tests/rustdoc-ui/infinite-recursive-type-impl-trait.stderr b/tests/rustdoc-ui/infinite-recursive-type-impl-trait.stderr
deleted file mode 100644
index a61577bd14a..00000000000
--- a/tests/rustdoc-ui/infinite-recursive-type-impl-trait.stderr
+++ /dev/null
@@ -1,16 +0,0 @@
-error[E0072]: recursive type `f::E` has infinite size
-  --> $DIR/infinite-recursive-type-impl-trait.rs:2:5
-   |
-LL |     enum E {
-   |     ^^^^^^
-LL |         V(E),
-   |           - recursive without indirection
-   |
-help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to break the cycle
-   |
-LL |         V(Box<E>),
-   |           ++++ +
-
-error: aborting due to previous error
-
-For more information about this error, try `rustc --explain E0072`.
diff --git a/tests/rustdoc/array-links.rs b/tests/rustdoc/array-links.rs
index 07f92ac51b9..e7c0ee2de1a 100644
--- a/tests/rustdoc/array-links.rs
+++ b/tests/rustdoc/array-links.rs
@@ -4,25 +4,25 @@
 pub struct MyBox<T: ?Sized>(*const T);
 
 // @has 'foo/fn.alpha.html'
-// @snapshot link_slice_u32 - '//pre[@class="rust fn"]/code'
+// @snapshot link_slice_u32 - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn alpha() -> &'static [u32; 1] {
     loop {}
 }
 
 // @has 'foo/fn.beta.html'
-// @snapshot link_slice_generic - '//pre[@class="rust fn"]/code'
+// @snapshot link_slice_generic - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn beta<T>() -> &'static [T; 1] {
     loop {}
 }
 
 // @has 'foo/fn.gamma.html'
-// @snapshot link_box_u32 - '//pre[@class="rust fn"]/code'
+// @snapshot link_box_u32 - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn gamma() -> MyBox<[u32; 1]> {
     loop {}
 }
 
 // @has 'foo/fn.delta.html'
-// @snapshot link_box_generic - '//pre[@class="rust fn"]/code'
+// @snapshot link_box_generic - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn delta<T>() -> MyBox<[T; 1]> {
     loop {}
 }
diff --git a/tests/rustdoc/assoc-consts.rs b/tests/rustdoc/assoc-consts.rs
index 3da19a13e53..77b139b644f 100644
--- a/tests/rustdoc/assoc-consts.rs
+++ b/tests/rustdoc/assoc-consts.rs
@@ -1,5 +1,5 @@
 pub trait Foo {
-    // @has assoc_consts/trait.Foo.html '//*[@class="rust trait"]' \
+    // @has assoc_consts/trait.Foo.html '//div[@class="item-decl"]/pre[@class="rust"]' \
     //      'const FOO: usize = 13usize;'
     // @has - '//*[@id="associatedconstant.FOO"]' 'const FOO: usize'
     const FOO: usize = 12 + 1;
diff --git a/tests/rustdoc/assoc-item-cast.rs b/tests/rustdoc/assoc-item-cast.rs
index a409d64131a..ab9702a24f4 100644
--- a/tests/rustdoc/assoc-item-cast.rs
+++ b/tests/rustdoc/assoc-item-cast.rs
@@ -10,5 +10,5 @@ pub trait AsExpression<T> {
 }
 
 // @has foo/type.AsExprOf.html
-// @has - '//pre[@class="rust typedef"]' 'type AsExprOf<Item, Type> = <Item as AsExpression<Type>>::Expression;'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'type AsExprOf<Item, Type> = <Item as AsExpression<Type>>::Expression;'
 pub type AsExprOf<Item, Type> = <Item as AsExpression<Type>>::Expression;
diff --git a/tests/rustdoc/assoc-types.rs b/tests/rustdoc/assoc-types.rs
index a9e5b8d0019..de36c8ffeff 100644
--- a/tests/rustdoc/assoc-types.rs
+++ b/tests/rustdoc/assoc-types.rs
@@ -12,8 +12,8 @@ pub trait Index<I: ?Sized> {
 }
 
 // @has assoc_types/fn.use_output.html
-// @has - '//*[@class="rust fn"]' '-> &T::Output'
-// @has - '//*[@class="rust fn"]//a[@href="trait.Index.html#associatedtype.Output"]' 'Output'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' '-> &T::Output'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]//a[@href="trait.Index.html#associatedtype.Output"]' 'Output'
 pub fn use_output<T: Index<usize>>(obj: &T, index: usize) -> &T::Output {
     obj.index(index)
 }
@@ -23,13 +23,13 @@ pub trait Feed {
 }
 
 // @has assoc_types/fn.use_input.html
-// @has - '//*[@class="rust fn"]' 'T::Input'
-// @has - '//*[@class="rust fn"]//a[@href="trait.Feed.html#associatedtype.Input"]' 'Input'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'T::Input'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]//a[@href="trait.Feed.html#associatedtype.Input"]' 'Input'
 pub fn use_input<T: Feed>(_feed: &T, _element: T::Input) { }
 
 // @has assoc_types/fn.cmp_input.html
-// @has - '//*[@class="rust fn"]' 'where T::Input: PartialEq<U::Input>'
-// @has - '//*[@class="rust fn"]//a[@href="trait.Feed.html#associatedtype.Input"]' 'Input'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'where T::Input: PartialEq<U::Input>'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]//a[@href="trait.Feed.html#associatedtype.Input"]' 'Input'
 pub fn cmp_input<T: Feed, U: Feed>(a: &T::Input, b: &U::Input) -> bool
     where T::Input: PartialEq<U::Input>
 {
diff --git a/tests/rustdoc/async-fn.rs b/tests/rustdoc/async-fn.rs
index af765c51ace..fb7ebb5f822 100644
--- a/tests/rustdoc/async-fn.rs
+++ b/tests/rustdoc/async-fn.rs
@@ -1,35 +1,35 @@
 // edition:2018
-// @has async_fn/fn.foo.html '//pre[@class="rust fn"]' 'pub async fn foo() -> Option<Foo>'
+// @has async_fn/fn.foo.html '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async fn foo() -> Option<Foo>'
 pub async fn foo() -> Option<Foo> {
     None
 }
 
-// @has async_fn/fn.bar.html '//pre[@class="rust fn"]' 'pub async fn bar(a: i32, b: i32) -> i32'
+// @has async_fn/fn.bar.html '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async fn bar(a: i32, b: i32) -> i32'
 pub async fn bar(a: i32, b: i32) -> i32 {
     0
 }
 
-// @has async_fn/fn.baz.html '//pre[@class="rust fn"]' 'pub async fn baz<T>(a: T) -> T'
+// @has async_fn/fn.baz.html '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async fn baz<T>(a: T) -> T'
 pub async fn baz<T>(a: T) -> T {
     a
 }
 
-// @has async_fn/fn.qux.html '//pre[@class="rust fn"]' 'pub async unsafe fn qux() -> char'
+// @has async_fn/fn.qux.html '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async unsafe fn qux() -> char'
 pub async unsafe fn qux() -> char {
     '⚠'
 }
 
-// @has async_fn/fn.mut_args.html '//pre[@class="rust fn"]' 'pub async fn mut_args(a: usize)'
+// @has async_fn/fn.mut_args.html '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async fn mut_args(a: usize)'
 pub async fn mut_args(mut a: usize) {}
 
-// @has async_fn/fn.mut_ref.html '//pre[@class="rust fn"]' 'pub async fn mut_ref(x: i32)'
+// @has async_fn/fn.mut_ref.html '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async fn mut_ref(x: i32)'
 pub async fn mut_ref(ref mut x: i32) {}
 
 trait Bar {}
 
 impl Bar for () {}
 
-// @has async_fn/fn.quux.html '//pre[@class="rust fn"]' 'pub async fn quux() -> impl Bar'
+// @has async_fn/fn.quux.html '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async fn quux() -> impl Bar'
 pub async fn quux() -> impl Bar {
     ()
 }
@@ -50,27 +50,27 @@ pub trait Pattern<'a> {}
 
 pub trait Trait<const N: usize> {}
 // @has async_fn/fn.const_generics.html
-// @has - '//pre[@class="rust fn"]' 'pub async fn const_generics<const N: usize>(_: impl Trait<N>)'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async fn const_generics<const N: usize>(_: impl Trait<N>)'
 pub async fn const_generics<const N: usize>(_: impl Trait<N>) {}
 
 // test that elided lifetimes are properly elided and not displayed as `'_`
 // regression test for #63037
 // @has async_fn/fn.elided.html
-// @has - '//pre[@class="rust fn"]' 'pub async fn elided(foo: &str) -> &str'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async fn elided(foo: &str) -> &str'
 pub async fn elided(foo: &str) -> &str {}
 // This should really be shown as written, but for implementation reasons it's difficult.
 // See `impl Clean for TyKind::Ref`.
 // @has async_fn/fn.user_elided.html
-// @has - '//pre[@class="rust fn"]' 'pub async fn user_elided(foo: &str) -> &str'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async fn user_elided(foo: &str) -> &str'
 pub async fn user_elided(foo: &'_ str) -> &str {}
 // @has async_fn/fn.static_trait.html
-// @has - '//pre[@class="rust fn"]' 'pub async fn static_trait(foo: &str) -> Box<dyn Bar>'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub async fn static_trait(foo: &str) -> Box<dyn Bar>'
 pub async fn static_trait(foo: &str) -> Box<dyn Bar> {}
 // @has async_fn/fn.lifetime_for_trait.html
-// @has - '//pre[@class="rust fn"]' "pub async fn lifetime_for_trait(foo: &str) -> Box<dyn Bar + '_>"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "pub async fn lifetime_for_trait(foo: &str) -> Box<dyn Bar + '_>"
 pub async fn lifetime_for_trait(foo: &str) -> Box<dyn Bar + '_> {}
 // @has async_fn/fn.elided_in_input_trait.html
-// @has - '//pre[@class="rust fn"]' "pub async fn elided_in_input_trait(t: impl Pattern<'_>)"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "pub async fn elided_in_input_trait(t: impl Pattern<'_>)"
 pub async fn elided_in_input_trait(t: impl Pattern<'_>) {}
 
 struct AsyncFdReadyGuard<'a, T> { x: &'a T }
@@ -88,8 +88,8 @@ impl Foo {
 
 // test named lifetimes, just in case
 // @has async_fn/fn.named.html
-// @has - '//pre[@class="rust fn"]' "pub async fn named<'a, 'b>(foo: &'a str) -> &'b str"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "pub async fn named<'a, 'b>(foo: &'a str) -> &'b str"
 pub async fn named<'a, 'b>(foo: &'a str) -> &'b str {}
 // @has async_fn/fn.named_trait.html
-// @has - '//pre[@class="rust fn"]' "pub async fn named_trait<'a, 'b>(foo: impl Pattern<'a>) -> impl Pattern<'b>"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "pub async fn named_trait<'a, 'b>(foo: impl Pattern<'a>) -> impl Pattern<'b>"
 pub async fn named_trait<'a, 'b>(foo: impl Pattern<'a>) -> impl Pattern<'b> {}
diff --git a/tests/rustdoc/attributes.rs b/tests/rustdoc/attributes.rs
index a36dadced87..70e2e5c2950 100644
--- a/tests/rustdoc/attributes.rs
+++ b/tests/rustdoc/attributes.rs
@@ -1,13 +1,13 @@
 #![crate_name = "foo"]
 
-// @has foo/fn.f.html '//*[@class="rust fn"]' '#[no_mangle]'
+// @has foo/fn.f.html '//div[@class="item-decl"]/pre[@class="rust"]' '#[no_mangle]'
 #[no_mangle]
 pub extern "C" fn f() {}
 
-// @has foo/fn.g.html '//*[@class="rust fn"]' '#[export_name = "bar"]'
+// @has foo/fn.g.html '//div[@class="item-decl"]/pre[@class="rust"]' '#[export_name = "bar"]'
 #[export_name = "bar"]
 pub extern "C" fn g() {}
 
-// @has foo/struct.Repr.html '//*[@class="item-decl"]' '#[repr(C, align(8))]'
+// @has foo/struct.Repr.html '//div[@class="item-decl"]' '#[repr(C, align(8))]'
 #[repr(C, align(8))]
 pub struct Repr;
diff --git a/tests/rustdoc/auxiliary/issue-85454.rs b/tests/rustdoc/auxiliary/issue-85454.rs
index 45664dfc382..5143968bbd4 100644
--- a/tests/rustdoc/auxiliary/issue-85454.rs
+++ b/tests/rustdoc/auxiliary/issue-85454.rs
@@ -1,5 +1,5 @@
 // @has issue_85454/trait.FromResidual.html
-// @has - '//pre[@class="rust trait"]' 'pub trait FromResidual<R = <Self as Try>::Residual> { fn from_residual(residual: R) -> Self; }'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub trait FromResidual<R = <Self as Try>::Residual> { fn from_residual(residual: R) -> Self; }'
 pub trait FromResidual<R = <Self as Try>::Residual> {
     fn from_residual(residual: R) -> Self;
 }
diff --git a/tests/rustdoc/const-fn.rs b/tests/rustdoc/const-fn.rs
index 28eba849ace..4366ad4d0ad 100644
--- a/tests/rustdoc/const-fn.rs
+++ b/tests/rustdoc/const-fn.rs
@@ -1,7 +1,7 @@
 #![crate_name = "foo"]
 
 // @has foo/fn.bar.html
-// @has - '//*[@class="rust fn"]' 'pub const fn bar() -> '
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub const fn bar() -> '
 /// foo
 pub const fn bar() -> usize {
     2
diff --git a/tests/rustdoc/const-generics/add-impl.rs b/tests/rustdoc/const-generics/add-impl.rs
index 6cbae9abebb..b5226ad3f78 100644
--- a/tests/rustdoc/const-generics/add-impl.rs
+++ b/tests/rustdoc/const-generics/add-impl.rs
@@ -2,7 +2,7 @@
 
 use std::ops::Add;
 
-// @has foo/struct.Simd.html '//pre[@class="rust struct"]' 'pub struct Simd<T, const WIDTH: usize>'
+// @has foo/struct.Simd.html '//div[@class="item-decl"]/pre[@class="rust"]' 'pub struct Simd<T, const WIDTH: usize>'
 pub struct Simd<T, const WIDTH: usize> {
     inner: T,
 }
diff --git a/tests/rustdoc/const-generics/const-generic-defaults.rs b/tests/rustdoc/const-generics/const-generic-defaults.rs
index 2693d9b5969..acc3b853e56 100644
--- a/tests/rustdoc/const-generics/const-generic-defaults.rs
+++ b/tests/rustdoc/const-generics/const-generic-defaults.rs
@@ -1,5 +1,5 @@
 #![crate_name = "foo"]
 
-// @has foo/struct.Foo.html '//pre[@class="rust struct"]' \
+// @has foo/struct.Foo.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub struct Foo<const M: usize = 10, const N: usize = M, T = i32>(_);'
 pub struct Foo<const M: usize = 10, const N: usize = M, T = i32>(T);
diff --git a/tests/rustdoc/const-generics/const-generics-docs.rs b/tests/rustdoc/const-generics/const-generics-docs.rs
index 5bf76e3c469..543332d2c32 100644
--- a/tests/rustdoc/const-generics/const-generics-docs.rs
+++ b/tests/rustdoc/const-generics/const-generics-docs.rs
@@ -3,21 +3,21 @@
 #![crate_name = "foo"]
 
 extern crate extern_crate;
-// @has foo/fn.extern_fn.html '//pre[@class="rust fn"]' \
+// @has foo/fn.extern_fn.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub fn extern_fn<const N: usize>() -> impl Iterator<Item = [u8; N]>'
 pub use extern_crate::extern_fn;
-// @has foo/struct.ExternTy.html '//pre[@class="rust struct"]' \
+// @has foo/struct.ExternTy.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub struct ExternTy<const N: usize> {'
 pub use extern_crate::ExternTy;
-// @has foo/type.TyAlias.html '//pre[@class="rust typedef"]' \
+// @has foo/type.TyAlias.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'type TyAlias<const N: usize> = ExternTy<N>;'
 pub use extern_crate::TyAlias;
-// @has foo/trait.WTrait.html '//pre[@class="rust trait"]' \
+// @has foo/trait.WTrait.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub trait WTrait<const N: usize, const M: usize>'
-// @has - '//*[@class="rust trait"]' 'fn hey<const P: usize>() -> usize'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'fn hey<const P: usize>() -> usize'
 pub use extern_crate::WTrait;
 
-// @has foo/trait.Trait.html '//pre[@class="rust trait"]' \
+// @has foo/trait.Trait.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub trait Trait<const N: usize>'
 // @has - '//*[@id="impl-Trait%3C1%3E-for-u8"]//h3[@class="code-header"]' 'impl Trait<1> for u8'
 // @has - '//*[@id="impl-Trait%3C2%3E-for-u8"]//h3[@class="code-header"]' 'impl Trait<2> for u8'
@@ -30,10 +30,10 @@ impl Trait<2> for u8 {}
 impl Trait<{1 + 2}> for u8 {}
 impl<const N: usize> Trait<N> for [u8; N] {}
 
-// @has foo/struct.Foo.html '//pre[@class="rust struct"]' \
+// @has foo/struct.Foo.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub struct Foo<const N: usize>where u8: Trait<N>'
 pub struct Foo<const N: usize> where u8: Trait<N>;
-// @has foo/struct.Bar.html '//pre[@class="rust struct"]' 'pub struct Bar<T, const N: usize>(_)'
+// @has foo/struct.Bar.html '//div[@class="item-decl"]/pre[@class="rust"]' 'pub struct Bar<T, const N: usize>(_)'
 pub struct Bar<T, const N: usize>([T; N]);
 
 // @has foo/struct.Foo.html '//*[@id="impl-Foo%3CM%3E"]/h3[@class="code-header"]' 'impl<const M: usize> Foo<M>where u8: Trait<M>'
@@ -56,32 +56,32 @@ impl<const M: usize> Bar<u8, M> {
     }
 }
 
-// @has foo/fn.test.html '//pre[@class="rust fn"]' \
+// @has foo/fn.test.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub fn test<const N: usize>() -> impl Trait<N>where u8: Trait<N>'
 pub fn test<const N: usize>() -> impl Trait<N> where u8: Trait<N> {
     2u8
 }
 
-// @has foo/fn.a_sink.html '//pre[@class="rust fn"]' \
+// @has foo/fn.a_sink.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub async fn a_sink<const N: usize>(v: [u8; N]) -> impl Trait<N>'
 pub async fn a_sink<const N: usize>(v: [u8; N]) -> impl Trait<N> {
     v
 }
 
-// @has foo/fn.b_sink.html '//pre[@class="rust fn"]' \
+// @has foo/fn.b_sink.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub async fn b_sink<const N: usize>(_: impl Trait<N>)'
 pub async fn b_sink<const N: usize>(_: impl Trait<N>) {}
 
-// @has foo/fn.concrete.html '//pre[@class="rust fn"]' \
+// @has foo/fn.concrete.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub fn concrete() -> [u8; 22]'
 pub fn concrete() -> [u8; 3 + std::mem::size_of::<u64>() << 1] {
     Default::default()
 }
 
-// @has foo/type.Faz.html '//pre[@class="rust typedef"]' \
+// @has foo/type.Faz.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'type Faz<const N: usize> = [u8; N];'
 pub type Faz<const N: usize> = [u8; N];
-// @has foo/type.Fiz.html '//pre[@class="rust typedef"]' \
+// @has foo/type.Fiz.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'type Fiz<const N: usize> = [[u8; N]; 48];'
 pub type Fiz<const N: usize> = [[u8; N]; 3 << 4];
 
@@ -91,7 +91,7 @@ macro_rules! define_me {
     }
 }
 
-// @has foo/struct.Foz.html '//pre[@class="rust struct"]' \
+// @has foo/struct.Foz.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub struct Foz<const N: usize>(_);'
 define_me!(Foz<N>);
 
@@ -103,13 +103,13 @@ impl<const N: usize> Q for [u8; N] {
     const ASSOC: usize = N;
 }
 
-// @has foo/fn.q_user.html '//pre[@class="rust fn"]' \
+// @has foo/fn.q_user.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub fn q_user() -> [u8; 13]'
 pub fn q_user() -> [u8; <[u8; 13] as Q>::ASSOC] {
     [0; <[u8; 13] as Q>::ASSOC]
 }
 
-// @has foo/union.Union.html '//pre[@class="rust union"]' \
+// @has foo/union.Union.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub union Union<const N: usize>'
 pub union Union<const N: usize> {
     // @has - //pre "pub arr: [u8; N]"
@@ -118,7 +118,7 @@ pub union Union<const N: usize> {
     pub another_arr: [(); N],
 }
 
-// @has foo/enum.Enum.html '//pre[@class="rust enum"]' \
+// @has foo/enum.Enum.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub enum Enum<const N: usize>'
 pub enum Enum<const N: usize> {
     // @has - //pre "Variant([u8; N])"
diff --git a/tests/rustdoc/const-generics/const-impl.rs b/tests/rustdoc/const-generics/const-impl.rs
index 75ee84279be..726fb8f0c34 100644
--- a/tests/rustdoc/const-generics/const-impl.rs
+++ b/tests/rustdoc/const-generics/const-impl.rs
@@ -8,7 +8,7 @@ pub enum Order {
     Unsorted,
 }
 
-// @has foo/struct.VSet.html '//pre[@class="rust struct"]' 'pub struct VSet<T, const ORDER: Order>'
+// @has foo/struct.VSet.html '//div[@class="item-decl"]/pre[@class="rust"]' 'pub struct VSet<T, const ORDER: Order>'
 // @has foo/struct.VSet.html '//*[@id="impl-Send-for-VSet%3CT%2C%20ORDER%3E"]/h3[@class="code-header"]' 'impl<T, const ORDER: Order> Send for VSet<T, ORDER>'
 // @has foo/struct.VSet.html '//*[@id="impl-Sync-for-VSet%3CT%2C%20ORDER%3E"]/h3[@class="code-header"]' 'impl<T, const ORDER: Order> Sync for VSet<T, ORDER>'
 pub struct VSet<T, const ORDER: Order> {
diff --git a/tests/rustdoc/const-generics/generic_const_exprs.rs b/tests/rustdoc/const-generics/generic_const_exprs.rs
index 215ee228eb8..c53cf6dcd05 100644
--- a/tests/rustdoc/const-generics/generic_const_exprs.rs
+++ b/tests/rustdoc/const-generics/generic_const_exprs.rs
@@ -2,6 +2,6 @@
 #![feature(generic_const_exprs)]
 #![allow(incomplete_features)]
 // make sure that `ConstEvaluatable` predicates dont cause rustdoc to ICE #77647
-// @has foo/struct.Ice.html '//pre[@class="rust struct"]' \
+// @has foo/struct.Ice.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub struct Ice<const N: usize>;'
 pub struct Ice<const N: usize> where [(); N + 1]:;
diff --git a/tests/rustdoc/const-generics/type-alias.rs b/tests/rustdoc/const-generics/type-alias.rs
index ebda5b19404..72473a11244 100644
--- a/tests/rustdoc/const-generics/type-alias.rs
+++ b/tests/rustdoc/const-generics/type-alias.rs
@@ -1,4 +1,4 @@
 #![crate_name = "foo"]
 
-// @has foo/type.CellIndex.html '//pre[@class="rust typedef"]' 'type CellIndex<const D: usize> = [i64; D];'
+// @has foo/type.CellIndex.html '//div[@class="item-decl"]/pre[@class="rust"]' 'type CellIndex<const D: usize> = [i64; D];'
 pub type CellIndex<const D: usize> = [i64; D];
diff --git a/tests/rustdoc/const-intrinsic.rs b/tests/rustdoc/const-intrinsic.rs
index 2fc486d01da..42f6ac7923b 100644
--- a/tests/rustdoc/const-intrinsic.rs
+++ b/tests/rustdoc/const-intrinsic.rs
@@ -6,20 +6,20 @@
 
 extern "rust-intrinsic" {
     // @has 'foo/fn.transmute.html'
-    // @has - '//pre[@class="rust fn"]' 'pub const unsafe extern "rust-intrinsic" fn transmute<T, U>(_: T) -> U'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub const unsafe extern "rust-intrinsic" fn transmute<T, U>(_: T) -> U'
     #[stable(since="1.0.0", feature="rust1")]
     #[rustc_const_stable(feature = "const_transmute", since = "1.56.0")]
     pub fn transmute<T, U>(_: T) -> U;
 
     // @has 'foo/fn.unreachable.html'
-    // @has - '//pre[@class="rust fn"]' 'pub unsafe extern "rust-intrinsic" fn unreachable() -> !'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub unsafe extern "rust-intrinsic" fn unreachable() -> !'
     #[stable(since="1.0.0", feature="rust1")]
     pub fn unreachable() -> !;
 }
 
 extern "C" {
     // @has 'foo/fn.needs_drop.html'
-    // @has - '//pre[@class="rust fn"]' 'pub unsafe extern "C" fn needs_drop() -> !'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub unsafe extern "C" fn needs_drop() -> !'
     #[stable(since="1.0.0", feature="rust1")]
     pub fn needs_drop() -> !;
 }
diff --git a/tests/rustdoc/fn-pointer-arg-name.rs b/tests/rustdoc/fn-pointer-arg-name.rs
index 4293d849df5..96c64ac4e02 100644
--- a/tests/rustdoc/fn-pointer-arg-name.rs
+++ b/tests/rustdoc/fn-pointer-arg-name.rs
@@ -1,5 +1,5 @@
 #![crate_name = "foo"]
 
 // @has foo/fn.f.html
-// @has - '//*[@class="rust fn"]' 'pub fn f(callback: fn(len: usize, foo: u32))'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn f(callback: fn(len: usize, foo: u32))'
 pub fn f(callback: fn(len: usize, foo: u32)) {}
diff --git a/tests/rustdoc/hide-complex-unevaluated-const-arguments.rs b/tests/rustdoc/hide-complex-unevaluated-const-arguments.rs
index 644a6e1cf33..406157ce26c 100644
--- a/tests/rustdoc/hide-complex-unevaluated-const-arguments.rs
+++ b/tests/rustdoc/hide-complex-unevaluated-const-arguments.rs
@@ -63,7 +63,7 @@ impl<const S: Struct, St: Stage + ?Sized> Helper<S> for St {
 // this test as long as one can ensure that private fields are not leaked!
 //
 // @has hide_complex_unevaluated_const_arguments/trait.Sub.html \
-//      '//*[@class="rust trait"]' \
+//      '//div[@class="item-decl"]/pre[@class="rust"]' \
 //      'pub trait Sub: Sup<{ _ }, { _ }> { }'
 pub trait Sub: Sup<{ 90 * 20 * 4 }, { Struct { private: () } }> {}
 
diff --git a/tests/rustdoc/impl-in-const-block.rs b/tests/rustdoc/impl-in-const-block.rs
deleted file mode 100644
index b44e7135246..00000000000
--- a/tests/rustdoc/impl-in-const-block.rs
+++ /dev/null
@@ -1,43 +0,0 @@
-// Regression test for #83026.
-// The goal of this test is to ensure that impl blocks inside
-// const expressions are documented as well.
-
-#![crate_name = "foo"]
-
-// @has 'foo/struct.A.html'
-// @has - '//*[@id="method.new"]/*[@class="code-header"]' 'pub fn new() -> A'
-// @has - '//*[@id="method.bar"]/*[@class="code-header"]' 'pub fn bar(&self)'
-// @has - '//*[@id="method.woo"]/*[@class="code-header"]' 'pub fn woo(&self)'
-// @has - '//*[@id="method.yoo"]/*[@class="code-header"]' 'pub fn yoo()'
-// @has - '//*[@id="method.yuu"]/*[@class="code-header"]' 'pub fn yuu()'
-pub struct A;
-
-const _: () = {
-    impl A {
-        const FOO: () = {
-            impl A {
-                pub fn woo(&self) {}
-            }
-        };
-
-        pub fn new() -> A {
-            A
-        }
-    }
-};
-pub const X: () = {
-    impl A {
-        pub fn bar(&self) {}
-    }
-};
-
-fn foo() {
-    impl A {
-        pub fn yoo() {}
-    }
-    const _: () = {
-        impl A {
-            pub fn yuu() {}
-        }
-    };
-}
diff --git a/tests/rustdoc/inline-default-methods.rs b/tests/rustdoc/inline-default-methods.rs
index c97644e7f87..a4ca928f333 100644
--- a/tests/rustdoc/inline-default-methods.rs
+++ b/tests/rustdoc/inline-default-methods.rs
@@ -4,6 +4,6 @@
 extern crate inline_default_methods;
 
 // @has inline_default_methods/trait.Foo.html
-// @has - '//*[@class="rust trait"]' 'fn bar(&self);'
-// @has - '//*[@class="rust trait"]' 'fn foo(&mut self) { ... }'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'fn bar(&self);'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'fn foo(&mut self) { ... }'
 pub use inline_default_methods::Foo;
diff --git a/tests/rustdoc/inline_cross/auxiliary/cross-glob.rs b/tests/rustdoc/inline_cross/auxiliary/cross-glob.rs
index cde7f68ff01..48672590a12 100644
--- a/tests/rustdoc/inline_cross/auxiliary/cross-glob.rs
+++ b/tests/rustdoc/inline_cross/auxiliary/cross-glob.rs
@@ -3,3 +3,5 @@
 pub struct SomeStruct;
 
 pub fn some_fn() {}
+
+pub enum Shadowed {}
diff --git a/tests/rustdoc/inline_cross/cross-glob.rs b/tests/rustdoc/inline_cross/cross-glob.rs
index f97da11a901..7a519d2d255 100644
--- a/tests/rustdoc/inline_cross/cross-glob.rs
+++ b/tests/rustdoc/inline_cross/cross-glob.rs
@@ -6,6 +6,11 @@ extern crate inner;
 
 // @has cross_glob/struct.SomeStruct.html
 // @has cross_glob/fn.some_fn.html
+// @!has cross_glob/enum.Shadowed.html
 // @!has cross_glob/index.html '//code' 'pub use inner::*;'
 #[doc(inline)]
 pub use inner::*;
+
+// This type shadows the glob-imported enum `Shadowed`.
+// @has cross_glob/type.Shadowed.html
+pub type Shadowed = u8;
diff --git a/tests/rustdoc/inline_cross/dyn_trait.rs b/tests/rustdoc/inline_cross/dyn_trait.rs
index fa760540e43..0da8bfc3a9a 100644
--- a/tests/rustdoc/inline_cross/dyn_trait.rs
+++ b/tests/rustdoc/inline_cross/dyn_trait.rs
@@ -22,10 +22,10 @@ pub use dyn_trait::Ty2;
 pub use dyn_trait::Ty3;
 
 // @has user/fn.func0.html
-// @has - '//pre[@class="rust fn"]' "func0(_: &dyn Fn())"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "func0(_: &dyn Fn())"
 // FIXME(fmease): Show placeholder-lifetime bound, render "func0(_: &(dyn Fn() + '_))"
 pub use dyn_trait::func0;
 
 // @has user/fn.func1.html
-// @has - '//pre[@class="rust fn"]' "func1<'func>(_: &(dyn Fn() + 'func))"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "func1<'func>(_: &(dyn Fn() + 'func))"
 pub use dyn_trait::func1;
diff --git a/tests/rustdoc/inline_cross/impl_trait.rs b/tests/rustdoc/inline_cross/impl_trait.rs
index 9c4f6465920..e8587209b61 100644
--- a/tests/rustdoc/inline_cross/impl_trait.rs
+++ b/tests/rustdoc/inline_cross/impl_trait.rs
@@ -4,37 +4,37 @@
 extern crate impl_trait_aux;
 
 // @has impl_trait/fn.func.html
-// @has - '//pre[@class="rust fn"]' "pub fn func<'a>(_x: impl Clone + Into<Vec<u8, Global>> + 'a)"
-// @!has - '//pre[@class="rust fn"]' 'where'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "pub fn func<'a>(_x: impl Clone + Into<Vec<u8, Global>> + 'a)"
+// @!has - '//div[@class="item-decl"]/pre[@class="rust"]' 'where'
 pub use impl_trait_aux::func;
 
 // @has impl_trait/fn.func2.html
-// @has - '//pre[@class="rust fn"]' "func2<T>("
-// @has - '//pre[@class="rust fn"]' "_x: impl Deref<Target = Option<T>> + Iterator<Item = T>,"
-// @has - '//pre[@class="rust fn"]' "_y: impl Iterator<Item = u8>)"
-// @!has - '//pre[@class="rust fn"]' 'where'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "func2<T>("
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "_x: impl Deref<Target = Option<T>> + Iterator<Item = T>,"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "_y: impl Iterator<Item = u8>)"
+// @!has - '//div[@class="item-decl"]/pre[@class="rust"]' 'where'
 pub use impl_trait_aux::func2;
 
 // @has impl_trait/fn.func3.html
-// @has - '//pre[@class="rust fn"]' "func3("
-// @has - '//pre[@class="rust fn"]' "_x: impl Iterator<Item = impl Iterator<Item = u8>> + Clone)"
-// @!has - '//pre[@class="rust fn"]' 'where'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "func3("
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "_x: impl Iterator<Item = impl Iterator<Item = u8>> + Clone)"
+// @!has - '//div[@class="item-decl"]/pre[@class="rust"]' 'where'
 pub use impl_trait_aux::func3;
 
 // @has impl_trait/fn.func4.html
-// @has - '//pre[@class="rust fn"]' "func4<T>("
-// @has - '//pre[@class="rust fn"]' "T: Iterator<Item = impl Clone>,"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "func4<T>("
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "T: Iterator<Item = impl Clone>,"
 pub use impl_trait_aux::func4;
 
 // @has impl_trait/fn.func5.html
-// @has - '//pre[@class="rust fn"]' "func5("
-// @has - '//pre[@class="rust fn"]' "_f: impl for<'any> Fn(&'any str, &'any str) -> bool + for<'r> Other<T<'r> = ()>,"
-// @has - '//pre[@class="rust fn"]' "_a: impl for<'alpha, 'beta> Auxiliary<'alpha, Item<'beta> = fn(_: &'beta ())>"
-// @!has - '//pre[@class="rust fn"]' 'where'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "func5("
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "_f: impl for<'any> Fn(&'any str, &'any str) -> bool + for<'r> Other<T<'r> = ()>,"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "_a: impl for<'alpha, 'beta> Auxiliary<'alpha, Item<'beta> = fn(_: &'beta ())>"
+// @!has - '//div[@class="item-decl"]/pre[@class="rust"]' 'where'
 pub use impl_trait_aux::func5;
 
 // @has impl_trait/fn.async_fn.html
-// @has - '//pre[@class="rust fn"]' "pub async fn async_fn()"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "pub async fn async_fn()"
 pub use impl_trait_aux::async_fn;
 
 // @has impl_trait/struct.Foo.html
diff --git a/tests/rustdoc/issue-20646.rs b/tests/rustdoc/issue-20646.rs
index 2589e27f215..a774b0ca7cd 100644
--- a/tests/rustdoc/issue-20646.rs
+++ b/tests/rustdoc/issue-20646.rs
@@ -13,7 +13,7 @@ pub trait Trait {
 }
 
 // @has issue_20646/fn.fun.html \
-//      '//*[@class="rust fn"]' 'where T: Trait<Output = i32>'
+//      '//div[@class="item-decl"]/pre[@class="rust"]' 'where T: Trait<Output = i32>'
 pub fn fun<T>(_: T) where T: Trait<Output=i32> {}
 
 pub mod reexport {
@@ -21,6 +21,6 @@ pub mod reexport {
     //      '//*[@id="associatedtype.Output"]' \
     //      'type Output'
     // @has issue_20646/reexport/fn.fun.html \
-    //      '//*[@class="rust fn"]' 'where T: Trait<Output = i32>'
+    //      '//div[@class="item-decl"]/pre[@class="rust"]' 'where T: Trait<Output = i32>'
     pub use issue_20646::{Trait, fun};
 }
diff --git a/tests/rustdoc/issue-20727-2.rs b/tests/rustdoc/issue-20727-2.rs
index 022ff290e1a..026b4f5acc9 100644
--- a/tests/rustdoc/issue-20727-2.rs
+++ b/tests/rustdoc/issue-20727-2.rs
@@ -5,18 +5,18 @@ extern crate issue_20727;
 
 // @has issue_20727_2/trait.Add.html
 pub trait Add<RHS = Self> {
-    // @has - '//*[@class="rust trait"]' 'trait Add<RHS = Self> {'
-    // @has - '//*[@class="rust trait"]' 'type Output;'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'trait Add<RHS = Self> {'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'type Output;'
     type Output;
 
-    // @has - '//*[@class="rust trait"]' 'fn add(self, rhs: RHS) -> Self::Output;'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'fn add(self, rhs: RHS) -> Self::Output;'
     fn add(self, rhs: RHS) -> Self::Output;
 }
 
 // @has issue_20727_2/reexport/trait.Add.html
 pub mod reexport {
-    // @has - '//*[@class="rust trait"]' 'trait Add<RHS = Self> {'
-    // @has - '//*[@class="rust trait"]' 'type Output;'
-    // @has - '//*[@class="rust trait"]' 'fn add(self, rhs: RHS) -> Self::Output;'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'trait Add<RHS = Self> {'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'type Output;'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'fn add(self, rhs: RHS) -> Self::Output;'
     pub use issue_20727::Add;
 }
diff --git a/tests/rustdoc/issue-20727-3.rs b/tests/rustdoc/issue-20727-3.rs
index 52032b75aea..741ce8023d7 100644
--- a/tests/rustdoc/issue-20727-3.rs
+++ b/tests/rustdoc/issue-20727-3.rs
@@ -7,18 +7,18 @@ pub trait Bar {}
 
 // @has issue_20727_3/trait.Deref2.html
 pub trait Deref2 {
-    // @has - '//*[@class="rust trait"]' 'trait Deref2 {'
-    // @has - '//*[@class="rust trait"]' 'type Target: Bar;'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'trait Deref2 {'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'type Target: Bar;'
     type Target: Bar;
 
-    // @has - '//*[@class="rust trait"]' 'fn deref(&self) -> Self::Target;'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'fn deref(&self) -> Self::Target;'
     fn deref(&self) -> Self::Target;
 }
 
 // @has issue_20727_3/reexport/trait.Deref2.html
 pub mod reexport {
-    // @has - '//*[@class="rust trait"]' 'trait Deref2 {'
-    // @has - '//*[@class="rust trait"]' 'type Target: Bar;'
-    // @has - '//*[@class="rust trait"]' 'fn deref(&self) -> Self::Target;'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'trait Deref2 {'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'type Target: Bar;'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'fn deref(&self) -> Self::Target;'
     pub use issue_20727::Deref2;
 }
diff --git a/tests/rustdoc/issue-20727-4.rs b/tests/rustdoc/issue-20727-4.rs
index 643f9387590..b8fac4da6ea 100644
--- a/tests/rustdoc/issue-20727-4.rs
+++ b/tests/rustdoc/issue-20727-4.rs
@@ -5,36 +5,36 @@ extern crate issue_20727;
 
 // @has issue_20727_4/trait.Index.html
 pub trait Index<Idx: ?Sized> {
-    // @has - '//*[@class="rust trait"]' 'trait Index<Idx: ?Sized> {'
-    // @has - '//*[@class="rust trait"]' 'type Output: ?Sized'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'trait Index<Idx: ?Sized> {'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'type Output: ?Sized'
     type Output: ?Sized;
 
-    // @has - '//*[@class="rust trait"]' \
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' \
     //        'fn index(&self, index: Idx) -> &Self::Output'
     fn index(&self, index: Idx) -> &Self::Output;
 }
 
 // @has issue_20727_4/trait.IndexMut.html
 pub trait IndexMut<Idx: ?Sized>: Index<Idx> {
-    // @has - '//*[@class="rust trait"]' \
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' \
     //        'trait IndexMut<Idx: ?Sized>: Index<Idx> {'
-    // @has - '//*[@class="rust trait"]' \
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' \
     //        'fn index_mut(&mut self, index: Idx) -> &mut Self::Output;'
     fn index_mut(&mut self, index: Idx) -> &mut Self::Output;
 }
 
 pub mod reexport {
     // @has issue_20727_4/reexport/trait.Index.html
-    // @has - '//*[@class="rust trait"]' 'trait Index<Idx>where Idx: ?Sized,{'
-    // @has - '//*[@class="rust trait"]' 'type Output: ?Sized'
-    // @has - '//*[@class="rust trait"]' \
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'trait Index<Idx>where Idx: ?Sized,{'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'type Output: ?Sized'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' \
     //        'fn index(&self, index: Idx) -> &Self::Output'
     pub use issue_20727::Index;
 
     // @has issue_20727_4/reexport/trait.IndexMut.html
-    // @has - '//*[@class="rust trait"]' \
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' \
     //        'trait IndexMut<Idx>: Index<Idx>where Idx: ?Sized,{'
-    // @has - '//*[@class="rust trait"]' \
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' \
     //        'fn index_mut(&mut self, index: Idx) -> &mut Self::Output;'
     pub use issue_20727::IndexMut;
 }
diff --git a/tests/rustdoc/issue-20727.rs b/tests/rustdoc/issue-20727.rs
index c1a98cd57da..df334821ccc 100644
--- a/tests/rustdoc/issue-20727.rs
+++ b/tests/rustdoc/issue-20727.rs
@@ -5,20 +5,20 @@ extern crate issue_20727;
 
 // @has issue_20727/trait.Deref.html
 pub trait Deref {
-    // @has - '//*[@class="rust trait"]' 'trait Deref {'
-    // @has - '//*[@class="rust trait"]' 'type Target: ?Sized;'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'trait Deref {'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'type Target: ?Sized;'
     type Target: ?Sized;
 
-    // @has - '//*[@class="rust trait"]' \
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' \
     //        "fn deref<'a>(&'a self) -> &'a Self::Target;"
     fn deref<'a>(&'a self) -> &'a Self::Target;
 }
 
 // @has issue_20727/reexport/trait.Deref.html
 pub mod reexport {
-    // @has - '//*[@class="rust trait"]' 'trait Deref {'
-    // @has - '//*[@class="rust trait"]' 'type Target: ?Sized;'
-    // @has - '//*[@class="rust trait"]' \
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'trait Deref {'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'type Target: ?Sized;'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' \
     //      "fn deref<'a>(&'a self) -> &'a Self::Target;"
     pub use issue_20727::Deref;
 }
diff --git a/tests/rustdoc/issue-22038.rs b/tests/rustdoc/issue-22038.rs
index ff5813dac80..19e626ba132 100644
--- a/tests/rustdoc/issue-22038.rs
+++ b/tests/rustdoc/issue-22038.rs
@@ -1,19 +1,19 @@
 extern "C" {
     // @has issue_22038/fn.foo1.html \
-    //      '//*[@class="rust fn"]' 'pub unsafe extern "C" fn foo1()'
+    //      '//div[@class="item-decl"]/pre[@class="rust"]' 'pub unsafe extern "C" fn foo1()'
     pub fn foo1();
 }
 
 extern "system" {
     // @has issue_22038/fn.foo2.html \
-    //      '//*[@class="rust fn"]' 'pub unsafe extern "system" fn foo2()'
+    //      '//div[@class="item-decl"]/pre[@class="rust"]' 'pub unsafe extern "system" fn foo2()'
     pub fn foo2();
 }
 
 // @has issue_22038/fn.bar.html \
-//      '//*[@class="rust fn"]' 'pub extern "C" fn bar()'
+//      '//div[@class="item-decl"]/pre[@class="rust"]' 'pub extern "C" fn bar()'
 pub extern "C" fn bar() {}
 
 // @has issue_22038/fn.baz.html \
-//      '//*[@class="rust fn"]' 'pub extern "system" fn baz()'
+//      '//div[@class="item-decl"]/pre[@class="rust"]' 'pub extern "system" fn baz()'
 pub extern "system" fn baz() {}
diff --git a/tests/rustdoc/issue-33302.rs b/tests/rustdoc/issue-33302.rs
index 1e4791e0125..b4c52e2f17a 100644
--- a/tests/rustdoc/issue-33302.rs
+++ b/tests/rustdoc/issue-33302.rs
@@ -6,17 +6,17 @@ macro_rules! make {
         pub struct S;
 
         // @has issue_33302/constant.CST.html \
-        //        '//pre[@class="rust const"]' 'pub const CST: i32'
+        //        '//div[@class="item-decl"]/pre[@class="rust"]' 'pub const CST: i32'
         pub const CST: i32 = ($n * $n);
         // @has issue_33302/static.ST.html \
-        //        '//pre[@class="rust static"]' 'pub static ST: i32'
+        //        '//div[@class="item-decl"]/pre[@class="rust"]' 'pub static ST: i32'
         pub static ST: i32 = ($n * $n);
 
         pub trait T<X> {
             fn ignore(_: &X) {}
             const C: X;
             // @has issue_33302/trait.T.html \
-            //        '//*[@class="rust trait"]' 'const D: i32'
+            //        '//div[@class="item-decl"]/pre[@class="rust"]' 'const D: i32'
             // @has - '//*[@id="associatedconstant.D"]' 'const D: i32'
             const D: i32 = ($n * $n);
         }
diff --git a/tests/rustdoc/issue-85454.rs b/tests/rustdoc/issue-85454.rs
index 3351b5c8350..74fc22b31dc 100644
--- a/tests/rustdoc/issue-85454.rs
+++ b/tests/rustdoc/issue-85454.rs
@@ -5,7 +5,7 @@
 extern crate issue_85454;
 
 // @has foo/trait.FromResidual.html
-// @has - '//pre[@class="rust trait"]' 'pub trait FromResidual<R = <Self as Try>::Residual> { fn from_residual(residual: R) -> Self; }'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub trait FromResidual<R = <Self as Try>::Residual> { fn from_residual(residual: R) -> Self; }'
 pub trait FromResidual<R = <Self as Try>::Residual> {
     fn from_residual(residual: R) -> Self;
 }
@@ -24,6 +24,6 @@ pub enum ControlFlow<B, C = ()> {
 
 pub mod reexport {
     // @has foo/reexport/trait.FromResidual.html
-    // @has - '//pre[@class="rust trait"]' 'pub trait FromResidual<R = <Self as Try>::Residual> { fn from_residual(residual: R) -> Self; }'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub trait FromResidual<R = <Self as Try>::Residual> { fn from_residual(residual: R) -> Self; }'
     pub use issue_85454::*;
 }
diff --git a/tests/rustdoc/issue-98697.rs b/tests/rustdoc/issue-98697.rs
index d50268509b2..884b63ac97f 100644
--- a/tests/rustdoc/issue-98697.rs
+++ b/tests/rustdoc/issue-98697.rs
@@ -8,8 +8,8 @@
 
 extern crate issue_98697_reexport_with_anonymous_lifetime;
 
-// @has issue_98697/fn.repro.html '//pre[@class="rust fn"]/code' 'fn repro<F>()where F: Fn(&str)'
-// @!has issue_98697/fn.repro.html '//pre[@class="rust fn"]/code' 'for<'
+// @has issue_98697/fn.repro.html '//div[@class="item-decl"]/pre[@class="rust"]/code' 'fn repro<F>()where F: Fn(&str)'
+// @!has issue_98697/fn.repro.html '//div[@class="item-decl"]/pre[@class="rust"]/code' 'for<'
 pub use issue_98697_reexport_with_anonymous_lifetime::repro;
 
 // @has issue_98697/struct.Extra.html '//div[@id="trait-implementations-list"]//h3[@class="code-header"]' 'impl MyTrait<&Extra> for Extra'
diff --git a/tests/rustdoc/legacy-const-generic.rs b/tests/rustdoc/legacy-const-generic.rs
index 46a50e2fc30..14533624e44 100644
--- a/tests/rustdoc/legacy-const-generic.rs
+++ b/tests/rustdoc/legacy-const-generic.rs
@@ -2,14 +2,14 @@
 #![feature(rustc_attrs)]
 
 // @has 'foo/fn.foo.html'
-// @has - '//*[@class="rust fn"]' 'fn foo(x: usize, const Y: usize, z: usize) -> [usize; 3]'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'fn foo(x: usize, const Y: usize, z: usize) -> [usize; 3]'
 #[rustc_legacy_const_generics(1)]
 pub fn foo<const Y: usize>(x: usize, z: usize) -> [usize; 3] {
     [x, Y, z]
 }
 
 // @has 'foo/fn.bar.html'
-// @has - '//*[@class="rust fn"]' 'fn bar(x: usize, const Y: usize, const Z: usize) -> [usize; 3]'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'fn bar(x: usize, const Y: usize, const Z: usize) -> [usize; 3]'
 #[rustc_legacy_const_generics(1, 2)]
 pub fn bar<const Y: usize, const Z: usize>(x: usize) -> [usize; 3] {
     [x, Y, z]
diff --git a/tests/rustdoc/lifetime-name.rs b/tests/rustdoc/lifetime-name.rs
index 5d30a745a61..0fb66059109 100644
--- a/tests/rustdoc/lifetime-name.rs
+++ b/tests/rustdoc/lifetime-name.rs
@@ -1,5 +1,5 @@
 #![crate_name = "foo"]
 
 // @has 'foo/type.Resolutions.html'
-// @has - '//*[@class="rust typedef"]' "pub type Resolutions<'tcx> = &'tcx u8;"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "pub type Resolutions<'tcx> = &'tcx u8;"
 pub type Resolutions<'tcx> = &'tcx u8;
diff --git a/tests/rustdoc/mut-params.rs b/tests/rustdoc/mut-params.rs
index f3ea6995839..3b862e651c9 100644
--- a/tests/rustdoc/mut-params.rs
+++ b/tests/rustdoc/mut-params.rs
@@ -13,6 +13,6 @@ impl Foo {
     pub fn bar(mut bar: ()) {}
 }
 
-// @count foo/fn.baz.html '//*[@class="rust fn"]' 1
-// @!has - '//*[@class="rust fn"]' 'mut'
+// @count foo/fn.baz.html '//div[@class="item-decl"]/pre[@class="rust"]' 1
+// @!has - '//div[@class="item-decl"]/pre[@class="rust"]' 'mut'
 pub fn baz(mut foo: Foo) {}
diff --git a/tests/rustdoc/normalize-assoc-item.rs b/tests/rustdoc/normalize-assoc-item.rs
index db56f68526b..659480479fd 100644
--- a/tests/rustdoc/normalize-assoc-item.rs
+++ b/tests/rustdoc/normalize-assoc-item.rs
@@ -19,12 +19,12 @@ impl Trait for isize {
     type X = <() as Trait>::X;
 }
 
-// @has 'normalize_assoc_item/fn.f.html' '//pre[@class="rust fn"]' 'pub fn f() -> isize'
+// @has 'normalize_assoc_item/fn.f.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn f() -> isize'
 pub fn f() -> <usize as Trait>::X {
     0
 }
 
-// @has 'normalize_assoc_item/fn.f2.html' '//pre[@class="rust fn"]' 'pub fn f2() -> fn() -> i32'
+// @has 'normalize_assoc_item/fn.f2.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn f2() -> fn() -> i32'
 pub fn f2() -> <isize as Trait>::X {
     todo!()
 }
@@ -49,10 +49,10 @@ impl<Inner: Trait> Trait for Generic<Inner> {
 // These can't be normalized because they depend on a generic parameter.
 // However the user can choose whether the text should be displayed as `Inner::X` or `<Inner as Trait>::X`.
 
-// @has 'normalize_assoc_item/struct.Unknown.html' '//pre[@class="rust struct"]' 'pub struct Unknown<Inner: Trait>(pub <Inner as Trait>::X);'
+// @has 'normalize_assoc_item/struct.Unknown.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub struct Unknown<Inner: Trait>(pub <Inner as Trait>::X);'
 pub struct Unknown<Inner: Trait>(pub <Inner as Trait>::X);
 
-// @has 'normalize_assoc_item/struct.Unknown2.html' '//pre[@class="rust struct"]' 'pub struct Unknown2<Inner: Trait>(pub Inner::X);'
+// @has 'normalize_assoc_item/struct.Unknown2.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub struct Unknown2<Inner: Trait>(pub Inner::X);'
 pub struct Unknown2<Inner: Trait>(pub Inner::X);
 
 trait Lifetimes<'a> {
@@ -63,20 +63,20 @@ impl<'a> Lifetimes<'a> for usize {
     type Y = &'a isize;
 }
 
-// @has 'normalize_assoc_item/fn.g.html' '//pre[@class="rust fn"]' "pub fn g() -> &isize"
+// @has 'normalize_assoc_item/fn.g.html' '//div[@class="item-decl"]/pre[@class="rust"]' "pub fn g() -> &isize"
 pub fn g() -> <usize as Lifetimes<'static>>::Y {
     &0
 }
 
-// @has 'normalize_assoc_item/constant.A.html' '//pre[@class="rust const"]' "pub const A: &isize"
+// @has 'normalize_assoc_item/constant.A.html' '//div[@class="item-decl"]/pre[@class="rust"]' "pub const A: &isize"
 pub const A: <usize as Lifetimes<'static>>::Y = &0;
 
 // test cross-crate re-exports
 extern crate inner;
-// @has 'normalize_assoc_item/fn.foo.html' '//pre[@class="rust fn"]' "pub fn foo() -> i32"
+// @has 'normalize_assoc_item/fn.foo.html' '//div[@class="item-decl"]/pre[@class="rust"]' "pub fn foo() -> i32"
 pub use inner::foo;
 
-// @has 'normalize_assoc_item/fn.h.html' '//pre[@class="rust fn"]' "pub fn h<T>() -> IntoIter<T, Global>"
+// @has 'normalize_assoc_item/fn.h.html' '//div[@class="item-decl"]/pre[@class="rust"]' "pub fn h<T>() -> IntoIter<T, Global>"
 pub fn h<T>() -> <Vec<T> as IntoIterator>::IntoIter {
     vec![].into_iter()
 }
diff --git a/tests/rustdoc/pub-method.rs b/tests/rustdoc/pub-method.rs
index fa7de0aff6a..0dca3f672cd 100644
--- a/tests/rustdoc/pub-method.rs
+++ b/tests/rustdoc/pub-method.rs
@@ -3,7 +3,7 @@
 #![crate_name = "foo"]
 
 // @has foo/fn.bar.html
-// @has - '//*[@class="rust fn"]' 'pub fn bar() -> '
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn bar() -> '
 /// foo
 pub fn bar() -> usize {
     2
diff --git a/tests/rustdoc/range-arg-pattern.rs b/tests/rustdoc/range-arg-pattern.rs
index 756939ae377..bdbcc47c9f2 100644
--- a/tests/rustdoc/range-arg-pattern.rs
+++ b/tests/rustdoc/range-arg-pattern.rs
@@ -1,5 +1,5 @@
 #![crate_name = "foo"]
 
 // @has foo/fn.f.html
-// @has - '//*[@class="rust fn"]' 'pub fn f(_: u8)'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn f(_: u8)'
 pub fn f(0u8..=255: u8) {}
diff --git a/tests/rustdoc/reexports-priv.rs b/tests/rustdoc/reexports-priv.rs
index 11364e7f707..35c90ba5d7b 100644
--- a/tests/rustdoc/reexports-priv.rs
+++ b/tests/rustdoc/reexports-priv.rs
@@ -32,7 +32,7 @@ pub(self) use reexports::BarSelf;
 // @!has 'foo/enum.BarLocal.html'
 use reexports::BarLocal;
 
-// @has 'foo/fn.foo.html' '//*[@class="rust fn"]' 'pub fn foo()'
+// @has 'foo/fn.foo.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn foo()'
 pub use reexports::foo;
 // @!has 'foo/fn.foo_crate.html'
 pub(crate) use reexports::foo_crate;
@@ -41,7 +41,7 @@ pub(self) use reexports::foo_self;
 // @!has 'foo/fn.foo_local.html'
 use reexports::foo_local;
 
-// @has 'foo/type.Type.html' '//*[@class="rust typedef"]' 'pub type Type ='
+// @has 'foo/type.Type.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub type Type ='
 pub use reexports::Type;
 // @!has 'foo/type.TypeCrate.html'
 pub(crate) use reexports::TypeCrate;
@@ -94,22 +94,22 @@ pub mod outer {
         // @!has 'foo/outer/inner/enum.BarLocal.html'
         use reexports::BarLocal;
 
-        // @has 'foo/outer/inner/fn.foo.html' '//*[@class="rust fn"]' 'pub fn foo()'
+        // @has 'foo/outer/inner/fn.foo.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn foo()'
         pub use reexports::foo;
-        // @has 'foo/outer/inner/fn.foo_crate.html' '//*[@class="rust fn"]' 'pub(crate) fn foo_crate()'
+        // @has 'foo/outer/inner/fn.foo_crate.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub(crate) fn foo_crate()'
         pub(crate) use reexports::foo_crate;
-        // @has 'foo/outer/inner/fn.foo_super.html' '//*[@class="rust fn"]' 'pub(in outer) fn foo_super()'
+        // @has 'foo/outer/inner/fn.foo_super.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub(in outer) fn foo_super()'
         pub(super) use::reexports::foo_super;
         // @!has 'foo/outer/inner/fn.foo_self.html'
         pub(self) use reexports::foo_self;
         // @!has 'foo/outer/inner/fn.foo_local.html'
         use reexports::foo_local;
 
-        // @has 'foo/outer/inner/type.Type.html' '//*[@class="rust typedef"]' 'pub type Type ='
+        // @has 'foo/outer/inner/type.Type.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub type Type ='
         pub use reexports::Type;
-        // @has 'foo/outer/inner/type.TypeCrate.html' '//*[@class="rust typedef"]' 'pub(crate) type TypeCrate ='
+        // @has 'foo/outer/inner/type.TypeCrate.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub(crate) type TypeCrate ='
         pub(crate) use reexports::TypeCrate;
-        // @has 'foo/outer/inner/type.TypeSuper.html' '//*[@class="rust typedef"]' 'pub(in outer) type TypeSuper ='
+        // @has 'foo/outer/inner/type.TypeSuper.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub(in outer) type TypeSuper ='
         pub(super) use reexports::TypeSuper;
         // @!has 'foo/outer/inner/type.TypeSelf.html'
         pub(self) use reexports::TypeSelf;
diff --git a/tests/rustdoc/reexports.rs b/tests/rustdoc/reexports.rs
index 9aa6d7224ba..65d305c6d2c 100644
--- a/tests/rustdoc/reexports.rs
+++ b/tests/rustdoc/reexports.rs
@@ -31,7 +31,7 @@ pub(self) use reexports::BarSelf;
 // @!has 'foo/enum.BarLocal.html'
 use reexports::BarLocal;
 
-// @has 'foo/fn.foo.html' '//*[@class="rust fn"]' 'pub fn foo()'
+// @has 'foo/fn.foo.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn foo()'
 pub use reexports::foo;
 // @!has 'foo/fn.foo_crate.html'
 pub(crate) use reexports::foo_crate;
@@ -40,7 +40,7 @@ pub(self) use reexports::foo_self;
 // @!has 'foo/fn.foo_local.html'
 use reexports::foo_local;
 
-// @has 'foo/type.Type.html' '//*[@class="rust typedef"]' 'pub type Type ='
+// @has 'foo/type.Type.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub type Type ='
 pub use reexports::Type;
 // @!has 'foo/type.TypeCrate.html'
 pub(crate) use reexports::TypeCrate;
@@ -93,7 +93,7 @@ pub mod outer {
         // @!has 'foo/outer/inner/enum.BarLocal.html'
         use reexports::BarLocal;
 
-        // @has 'foo/outer/inner/fn.foo.html' '//*[@class="rust fn"]' 'pub fn foo()'
+        // @has 'foo/outer/inner/fn.foo.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn foo()'
         pub use reexports::foo;
         // @!has 'foo/outer/inner/fn.foo_crate.html'
         pub(crate) use reexports::foo_crate;
@@ -104,7 +104,7 @@ pub mod outer {
         // @!has 'foo/outer/inner/fn.foo_local.html'
         use reexports::foo_local;
 
-        // @has 'foo/outer/inner/type.Type.html' '//*[@class="rust typedef"]' 'pub type Type ='
+        // @has 'foo/outer/inner/type.Type.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub type Type ='
         pub use reexports::Type;
         // @!has 'foo/outer/inner/type.TypeCrate.html'
         pub(crate) use reexports::TypeCrate;
diff --git a/tests/rustdoc/rfc-2632-const-trait-impl.rs b/tests/rustdoc/rfc-2632-const-trait-impl.rs
index 7ed9d6729b6..a229a4e29fe 100644
--- a/tests/rustdoc/rfc-2632-const-trait-impl.rs
+++ b/tests/rustdoc/rfc-2632-const-trait-impl.rs
@@ -12,10 +12,10 @@ use std::marker::Destruct;
 
 pub struct S<T>(T);
 
-// @!has foo/trait.Tr.html '//pre[@class="rust trait"]/code/a[@class="trait"]' '~const'
-// @has - '//pre[@class="rust trait"]/code/a[@class="trait"]' 'Clone'
-// @!has - '//pre[@class="rust trait"]/code/span[@class="where"]' '~const'
-// @has - '//pre[@class="rust trait"]/code/span[@class="where"]' ': Clone'
+// @!has foo/trait.Tr.html '//div[@class="item-decl"]/pre[@class="rust"]/code/a[@class="trait"]' '~const'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]/code/a[@class="trait"]' 'Clone'
+// @!has - '//div[@class="item-decl"]/pre[@class="rust"]/code/span[@class="where"]' '~const'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]/code/span[@class="where"]' ': Clone'
 #[const_trait]
 pub trait Tr<T> {
     // @!has - '//section[@id="method.a"]/h4[@class="code-header"]' '~const'
@@ -45,10 +45,10 @@ where
     }
 }
 
-// @!has foo/fn.foo.html '//pre[@class="rust fn"]/code/a[@class="trait"]' '~const'
-// @has - '//pre[@class="rust fn"]/code/a[@class="trait"]' 'Clone'
-// @!has - '//pre[@class="rust fn"]/code/span[@class="where fmt-newline"]' '~const'
-// @has - '//pre[@class="rust fn"]/code/span[@class="where fmt-newline"]' ': Clone'
+// @!has foo/fn.foo.html '//div[@class="item-decl"]/pre[@class="rust"]/code/a[@class="trait"]' '~const'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]/code/a[@class="trait"]' 'Clone'
+// @!has - '//div[@class="item-decl"]/pre[@class="rust"]/code/span[@class="where fmt-newline"]' '~const'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]/code/span[@class="where fmt-newline"]' ': Clone'
 pub const fn foo<F: ~const Clone + ~const Destruct>()
 where
     Option<F>: ~const Clone + ~const Destruct,
diff --git a/tests/rustdoc/safe-intrinsic.rs b/tests/rustdoc/safe-intrinsic.rs
index d08abdaeb14..0b65bf1dfed 100644
--- a/tests/rustdoc/safe-intrinsic.rs
+++ b/tests/rustdoc/safe-intrinsic.rs
@@ -7,16 +7,16 @@
 
 extern "rust-intrinsic" {
     // @has 'foo/fn.abort.html'
-    // @has - '//pre[@class="rust fn"]' 'pub extern "rust-intrinsic" fn abort() -> !'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub extern "rust-intrinsic" fn abort() -> !'
     #[rustc_safe_intrinsic]
     pub fn abort() -> !;
     // @has 'foo/fn.unreachable.html'
-    // @has - '//pre[@class="rust fn"]' 'pub unsafe extern "rust-intrinsic" fn unreachable() -> !'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub unsafe extern "rust-intrinsic" fn unreachable() -> !'
     pub fn unreachable() -> !;
 }
 
 extern "C" {
     // @has 'foo/fn.needs_drop.html'
-    // @has - '//pre[@class="rust fn"]' 'pub unsafe extern "C" fn needs_drop() -> !'
+    // @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub unsafe extern "C" fn needs_drop() -> !'
     pub fn needs_drop() -> !;
 }
diff --git a/tests/rustdoc/slice-links.rs b/tests/rustdoc/slice-links.rs
index 9a78e963e30..67137fdcab2 100644
--- a/tests/rustdoc/slice-links.rs
+++ b/tests/rustdoc/slice-links.rs
@@ -4,25 +4,25 @@
 pub struct MyBox<T: ?Sized>(*const T);
 
 // @has 'foo/fn.alpha.html'
-// @snapshot link_slice_u32 - '//pre[@class="rust fn"]/code'
+// @snapshot link_slice_u32 - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn alpha() -> &'static [u32] {
     loop {}
 }
 
 // @has 'foo/fn.beta.html'
-// @snapshot link_slice_generic - '//pre[@class="rust fn"]/code'
+// @snapshot link_slice_generic - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn beta<T>() -> &'static [T] {
     loop {}
 }
 
 // @has 'foo/fn.gamma.html'
-// @snapshot link_box_u32 - '//pre[@class="rust fn"]/code'
+// @snapshot link_box_u32 - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn gamma() -> MyBox<[u32]> {
     loop {}
 }
 
 // @has 'foo/fn.delta.html'
-// @snapshot link_box_generic - '//pre[@class="rust fn"]/code'
+// @snapshot link_box_generic - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn delta<T>() -> MyBox<[T]> {
     loop {}
 }
diff --git a/tests/rustdoc/struct-arg-pattern.rs b/tests/rustdoc/struct-arg-pattern.rs
index 3c0369e3d34..3bfb43a0bef 100644
--- a/tests/rustdoc/struct-arg-pattern.rs
+++ b/tests/rustdoc/struct-arg-pattern.rs
@@ -4,7 +4,7 @@ struct BodyId {
     hir_id: usize,
 }
 
-// @has 'foo/fn.body_owner.html' '//*[@class="rust fn"]' 'pub fn body_owner(_: BodyId)'
+// @has 'foo/fn.body_owner.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn body_owner(_: BodyId)'
 pub fn body_owner(BodyId { hir_id }: BodyId) {
     // ...
 }
diff --git a/tests/rustdoc/test-parens.rs b/tests/rustdoc/test-parens.rs
index d9b9c7957d9..f5fdb1f52bf 100644
--- a/tests/rustdoc/test-parens.rs
+++ b/tests/rustdoc/test-parens.rs
@@ -1,5 +1,5 @@
 #![crate_name = "foo"]
 
 // @has foo/fn.foo.html
-// @has - '//*[@class="rust fn"]' "_: &(dyn ToString + 'static)"
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' "_: &(dyn ToString + 'static)"
 pub fn foo(_: &(ToString + 'static)) {}
diff --git a/tests/rustdoc/toggle-item-contents.rs b/tests/rustdoc/toggle-item-contents.rs
index 87240f233ff..5d34ec09b66 100644
--- a/tests/rustdoc/toggle-item-contents.rs
+++ b/tests/rustdoc/toggle-item-contents.rs
@@ -81,8 +81,8 @@ pub enum EnumStructVariant {
 }
 
 // @has 'toggle_item_contents/enum.LargeEnum.html'
-// @count - '//*[@class="rust enum"]//details[@class="toggle type-contents-toggle"]' 1
-// @has - '//*[@class="rust enum"]//details[@class="toggle type-contents-toggle"]' 'Show 13 variants'
+// @count - '//div[@class="item-decl"]/pre//details[@class="toggle type-contents-toggle"]' 1
+// @has - '//div[@class="item-decl"]/pre//details[@class="toggle type-contents-toggle"]' 'Show 13 variants'
 pub enum LargeEnum {
     A, B, C, D, E, F(u8), G, H, I, J, K, L, M
 }
diff --git a/tests/rustdoc/tuple-struct-fields-doc.rs b/tests/rustdoc/tuple-struct-fields-doc.rs
index 8ab1143d1f7..d72c10f2b25 100644
--- a/tests/rustdoc/tuple-struct-fields-doc.rs
+++ b/tests/rustdoc/tuple-struct-fields-doc.rs
@@ -19,7 +19,7 @@ pub struct Foo(
 );
 
 // @has foo/enum.Bar.html
-// @has - '//pre[@class="rust enum"]' 'BarVariant(String),'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'BarVariant(String),'
 // @matches - '//*[@id="variant.BarVariant.fields"]/h4' '^Tuple Fields$'
 // @has - '//*[@id="variant.BarVariant.field.0"]' '0: String'
 // @has - '//*[@id="variant.BarVariant.fields"]//*[@class="docblock"]' 'Hello docs'
diff --git a/tests/rustdoc/tuples.rs b/tests/rustdoc/tuples.rs
index 62e2f9e7ef2..e716de8b55c 100644
--- a/tests/rustdoc/tuples.rs
+++ b/tests/rustdoc/tuples.rs
@@ -1,20 +1,20 @@
 #![crate_name = "foo"]
 
 // @has foo/fn.tuple0.html //pre 'pub fn tuple0(x: ())'
-// @snapshot link_unit - '//pre[@class="rust fn"]/code'
+// @snapshot link_unit - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn tuple0(x: ()) -> () { x }
 // @has foo/fn.tuple1.html //pre 'pub fn tuple1(x: (i32,)) -> (i32,)'
-// @snapshot link1_i32 - '//pre[@class="rust fn"]/code'
+// @snapshot link1_i32 - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn tuple1(x: (i32,)) -> (i32,) { x }
 // @has foo/fn.tuple2.html //pre 'pub fn tuple2(x: (i32, i32)) -> (i32, i32)'
-// @snapshot link2_i32 - '//pre[@class="rust fn"]/code'
+// @snapshot link2_i32 - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn tuple2(x: (i32, i32)) -> (i32, i32) { x }
 // @has foo/fn.tuple1_t.html //pre 'pub fn tuple1_t<T>(x: (T,)) -> (T,)'
-// @snapshot link1_t - '//pre[@class="rust fn"]/code'
+// @snapshot link1_t - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn tuple1_t<T>(x: (T,)) -> (T,) { x }
 // @has foo/fn.tuple2_t.html //pre 'pub fn tuple2_t<T>(x: (T, T)) -> (T, T)'
-// @snapshot link2_t - '//pre[@class="rust fn"]/code'
+// @snapshot link2_t - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn tuple2_t<T>(x: (T, T)) -> (T, T) { x }
 // @has foo/fn.tuple2_tu.html //pre 'pub fn tuple2_tu<T, U>(x: (T, U)) -> (T, U)'
-// @snapshot link2_tu - '//pre[@class="rust fn"]/code'
+// @snapshot link2_tu - '//div[@class="item-decl"]/pre[@class="rust"]/code'
 pub fn tuple2_tu<T, U>(x: (T, U)) -> (T, U) { x }
diff --git a/tests/rustdoc/unit-return.rs b/tests/rustdoc/unit-return.rs
index ae3a6031519..353cd1c4772 100644
--- a/tests/rustdoc/unit-return.rs
+++ b/tests/rustdoc/unit-return.rs
@@ -4,14 +4,14 @@
 
 extern crate unit_return;
 
-// @has 'foo/fn.f0.html' '//*[@class="rust fn"]' 'F: FnMut(u8) + Clone'
+// @has 'foo/fn.f0.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'F: FnMut(u8) + Clone'
 pub fn f0<F: FnMut(u8) + Clone>(f: F) {}
 
-// @has 'foo/fn.f1.html' '//*[@class="rust fn"]' 'F: FnMut(u16) + Clone'
+// @has 'foo/fn.f1.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'F: FnMut(u16) + Clone'
 pub fn f1<F: FnMut(u16) -> () + Clone>(f: F) {}
 
-// @has 'foo/fn.f2.html' '//*[@class="rust fn"]' 'F: FnMut(u32) + Clone'
+// @has 'foo/fn.f2.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'F: FnMut(u32) + Clone'
 pub use unit_return::f2;
 
-// @has 'foo/fn.f3.html' '//*[@class="rust fn"]' 'F: FnMut(u64) + Clone'
+// @has 'foo/fn.f3.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'F: FnMut(u64) + Clone'
 pub use unit_return::f3;
diff --git a/tests/rustdoc/where-sized.rs b/tests/rustdoc/where-sized.rs
index fe7cad8c3ef..c0c085e6ac7 100644
--- a/tests/rustdoc/where-sized.rs
+++ b/tests/rustdoc/where-sized.rs
@@ -1,6 +1,6 @@
 #![crate_name = "foo"]
 
 // @has foo/fn.foo.html
-// @has - '//*[@class="rust fn"]' 'pub fn foo<X, Y: ?Sized>(_: &X)'
-// @has - '//*[@class="rust fn"]' 'where X: ?Sized,'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn foo<X, Y: ?Sized>(_: &X)'
+// @has - '//div[@class="item-decl"]/pre[@class="rust"]' 'where X: ?Sized,'
 pub fn foo<X, Y: ?Sized>(_: &X) where X: ?Sized {}
diff --git a/tests/rustdoc/where.SWhere_Simd_item-decl.html b/tests/rustdoc/where.SWhere_Simd_item-decl.html
index 6c1b5d31513..f84cb3753cb 100644
--- a/tests/rustdoc/where.SWhere_Simd_item-decl.html
+++ b/tests/rustdoc/where.SWhere_Simd_item-decl.html
@@ -1 +1 @@
-<div class="item-decl"><pre class="rust struct"><code>pub struct Simd&lt;T&gt;(_)<br /><span class="where">where<br />&#160;&#160;&#160;&#160;T: <a class="trait" href="trait.MyTrait.html" title="trait foo::MyTrait">MyTrait</a></span>;</code></pre></div>
\ No newline at end of file
+<div class="item-decl"><pre class="rust"><code>pub struct Simd&lt;T&gt;(_)<br /><span class="where">where<br />&#160;&#160;&#160;&#160;T: <a class="trait" href="trait.MyTrait.html" title="trait foo::MyTrait">MyTrait</a></span>;</code></pre></div>
\ No newline at end of file
diff --git a/tests/rustdoc/where.SWhere_TraitWhere_item-decl.html b/tests/rustdoc/where.SWhere_TraitWhere_item-decl.html
index d5d6c556d80..85b62667427 100644
--- a/tests/rustdoc/where.SWhere_TraitWhere_item-decl.html
+++ b/tests/rustdoc/where.SWhere_TraitWhere_item-decl.html
@@ -1,4 +1,4 @@
-<div class="item-decl"><pre class="rust trait"><code>pub trait TraitWhere {
+<div class="item-decl"><pre class="rust"><code>pub trait TraitWhere {
     type <a href="#associatedtype.Item" class="associatedtype">Item</a>&lt;'a&gt;<br />&#160;&#160;&#160;&#160;<span class="where">where<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Self: 'a</span>;
 
     fn <a href="#method.func" class="fn">func</a>(self)<br />&#160;&#160;&#160;&#160;<span class="where">where<br />&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;Self: <a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a></span>,
diff --git a/tests/rustdoc/where.rs b/tests/rustdoc/where.rs
index 8b5bce28f5a..3ac0c6872a8 100644
--- a/tests/rustdoc/where.rs
+++ b/tests/rustdoc/where.rs
@@ -57,6 +57,6 @@ pub enum Foxtrot<F> { Foxtrot1(F) }
 //          "impl<F> MyTrait for Foxtrot<F>where F: MyTrait"
 impl<F> MyTrait for Foxtrot<F>where F: MyTrait {}
 
-// @has foo/type.Golf.html '//pre[@class="rust typedef"]' \
+// @has foo/type.Golf.html '//div[@class="item-decl"]/pre[@class="rust"]' \
 //          "type Golf<T>where T: Clone, = (T, T)"
 pub type Golf<T> where T: Clone = (T, T);
diff --git a/tests/rustdoc/whitespace-after-where-clause.enum.html b/tests/rustdoc/whitespace-after-where-clause.enum.html
index f7663e4616a..20bde549a03 100644
--- a/tests/rustdoc/whitespace-after-where-clause.enum.html
+++ b/tests/rustdoc/whitespace-after-where-clause.enum.html
@@ -1,4 +1,4 @@
-<div class="item-decl"><pre class="rust enum"><code>pub enum Cow&lt;'a, B&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + ?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a,</span>{
+<div class="item-decl"><pre class="rust"><code>pub enum Cow&lt;'a, B&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + ?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a,</span>{
     Borrowed(<a class="primitive" href="{{channel}}/std/primitive.reference.html">&amp;'a </a>B),
     Whatever(<a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a>),
 }</code></pre></div>
\ No newline at end of file
diff --git a/tests/rustdoc/whitespace-after-where-clause.enum2.html b/tests/rustdoc/whitespace-after-where-clause.enum2.html
index ac7d7759821..d9fc0c22309 100644
--- a/tests/rustdoc/whitespace-after-where-clause.enum2.html
+++ b/tests/rustdoc/whitespace-after-where-clause.enum2.html
@@ -1,4 +1,4 @@
-<div class="item-decl"><pre class="rust enum"><code>pub enum Cow2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
+<div class="item-decl"><pre class="rust"><code>pub enum Cow2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
     Borrowed(<a class="primitive" href="{{channel}}/std/primitive.reference.html">&amp;'a </a>B),
     Whatever(<a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a>),
 }</code></pre></div>
\ No newline at end of file
diff --git a/tests/rustdoc/whitespace-after-where-clause.struct.html b/tests/rustdoc/whitespace-after-where-clause.struct.html
index fa3f224e7ad..f375265d7c1 100644
--- a/tests/rustdoc/whitespace-after-where-clause.struct.html
+++ b/tests/rustdoc/whitespace-after-where-clause.struct.html
@@ -1,4 +1,4 @@
-<div class="item-decl"><pre class="rust struct"><code>pub struct Struct&lt;'a, B&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + ?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a,</span>{
+<div class="item-decl"><pre class="rust"><code>pub struct Struct&lt;'a, B&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + ?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a,</span>{
     pub a: <a class="primitive" href="{{channel}}/std/primitive.reference.html">&amp;'a </a>B,
     pub b: <a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a>,
 }</code></pre></div>
\ No newline at end of file
diff --git a/tests/rustdoc/whitespace-after-where-clause.struct2.html b/tests/rustdoc/whitespace-after-where-clause.struct2.html
index fb06b0f77c5..1c59962eb1c 100644
--- a/tests/rustdoc/whitespace-after-where-clause.struct2.html
+++ b/tests/rustdoc/whitespace-after-where-clause.struct2.html
@@ -1,4 +1,4 @@
-<div class="item-decl"><pre class="rust struct"><code>pub struct Struct2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
+<div class="item-decl"><pre class="rust"><code>pub struct Struct2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
     pub a: <a class="primitive" href="{{channel}}/std/primitive.reference.html">&amp;'a </a>B,
     pub b: <a class="primitive" href="{{channel}}/std/primitive.u32.html">u32</a>,
 }</code></pre></div>
\ No newline at end of file
diff --git a/tests/rustdoc/whitespace-after-where-clause.trait.html b/tests/rustdoc/whitespace-after-where-clause.trait.html
index 50cfe362328..a2df06e7736 100644
--- a/tests/rustdoc/whitespace-after-where-clause.trait.html
+++ b/tests/rustdoc/whitespace-after-where-clause.trait.html
@@ -1,4 +1,4 @@
-<div class="item-decl"><pre class="rust trait"><code>pub trait ToOwned&lt;T&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;T: <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>,</span>{
+<div class="item-decl"><pre class="rust"><code>pub trait ToOwned&lt;T&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;T: <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>,</span>{
     type <a href="#associatedtype.Owned" class="associatedtype">Owned</a>;
 
     fn <a href="#tymethod.to_owned" class="fn">to_owned</a>(&amp;self) -&gt; Self::<a class="associatedtype" href="trait.ToOwned.html#associatedtype.Owned" title="type foo::ToOwned::Owned">Owned</a>;
diff --git a/tests/rustdoc/whitespace-after-where-clause.trait2.html b/tests/rustdoc/whitespace-after-where-clause.trait2.html
index 21eb89b7501..2bfd6f7685a 100644
--- a/tests/rustdoc/whitespace-after-where-clause.trait2.html
+++ b/tests/rustdoc/whitespace-after-where-clause.trait2.html
@@ -1,4 +1,4 @@
-<div class="item-decl"><pre class="rust trait"><code>pub trait ToOwned2&lt;T:&#160;<a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; {
+<div class="item-decl"><pre class="rust"><code>pub trait ToOwned2&lt;T:&#160;<a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; {
     type <a href="#associatedtype.Owned" class="associatedtype">Owned</a>;
 
     fn <a href="#tymethod.to_owned" class="fn">to_owned</a>(&amp;self) -&gt; Self::<a class="associatedtype" href="trait.ToOwned2.html#associatedtype.Owned" title="type foo::ToOwned2::Owned">Owned</a>;
diff --git a/tests/rustdoc/whitespace-after-where-clause.union.html b/tests/rustdoc/whitespace-after-where-clause.union.html
index 7bb177debc3..066f8f87b16 100644
--- a/tests/rustdoc/whitespace-after-where-clause.union.html
+++ b/tests/rustdoc/whitespace-after-where-clause.union.html
@@ -1,3 +1,3 @@
-<div class="item-decl"><pre class="rust union"><code>pub union Union&lt;'a, B&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + ?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a,</span>{
+<div class="item-decl"><pre class="rust"><code>pub union Union&lt;'a, B&gt;<span class="where fmt-newline">where<br />&#160;&#160;&#160;&#160;B: <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + ?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + 'a,</span>{
     /* private fields */
 }</code></pre></div>
\ No newline at end of file
diff --git a/tests/rustdoc/whitespace-after-where-clause.union2.html b/tests/rustdoc/whitespace-after-where-clause.union2.html
index 0d237df53c7..6b48c5dbd3e 100644
--- a/tests/rustdoc/whitespace-after-where-clause.union2.html
+++ b/tests/rustdoc/whitespace-after-where-clause.union2.html
@@ -1,3 +1,3 @@
-<div class="item-decl"><pre class="rust union"><code>pub union Union2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
+<div class="item-decl"><pre class="rust"><code>pub union Union2&lt;'a, B:&#160;?<a class="trait" href="{{channel}}/core/marker/trait.Sized.html" title="trait core::marker::Sized">Sized</a> + <a class="trait" href="trait.ToOwned.html" title="trait foo::ToOwned">ToOwned</a>&lt;dyn <a class="trait" href="{{channel}}/core/clone/trait.Clone.html" title="trait core::clone::Clone">Clone</a>&gt; + 'a&gt; {
     /* private fields */
 }</code></pre></div>
\ No newline at end of file
diff --git a/tests/rustdoc/wrapping.rs b/tests/rustdoc/wrapping.rs
index 8d8221bcdf2..178b8adc3f0 100644
--- a/tests/rustdoc/wrapping.rs
+++ b/tests/rustdoc/wrapping.rs
@@ -1,5 +1,5 @@
 use std::fmt::Debug;
 
-// @has 'wrapping/fn.foo.html' '//pre[@class="rust fn"]' 'pub fn foo() -> impl Debug'
-// @count - '//pre[@class="rust fn"]/br' 0
+// @has 'wrapping/fn.foo.html' '//div[@class="item-decl"]/pre[@class="rust"]' 'pub fn foo() -> impl Debug'
+// @count - '//div[@class="item-decl"]/pre[@class="rust"]/br' 0
 pub fn foo() -> impl Debug {}
diff --git a/tests/ui-fulldeps/mod_dir_path_canonicalized.rs b/tests/ui-fulldeps/mod_dir_path_canonicalized.rs
index ff1be080415..bdfd9628c48 100644
--- a/tests/ui-fulldeps/mod_dir_path_canonicalized.rs
+++ b/tests/ui-fulldeps/mod_dir_path_canonicalized.rs
@@ -2,6 +2,7 @@
 // Testing that a librustc_ast can parse modules with canonicalized base path
 // ignore-cross-compile
 // ignore-remote
+// no-remap-src-base: Reading `file!()` (expectedly) fails when enabled.
 
 #![feature(rustc_private)]
 
diff --git a/tests/ui/anonymous-higher-ranked-lifetime.stderr b/tests/ui/anonymous-higher-ranked-lifetime.stderr
index afb7f8fea92..c023d1b1590 100644
--- a/tests/ui/anonymous-higher-ranked-lifetime.stderr
+++ b/tests/ui/anonymous-higher-ranked-lifetime.stderr
@@ -16,7 +16,7 @@ LL | fn f1<F>(_: F) where F: Fn(&(), &()) {}
 help: consider borrowing the argument
    |
 LL |     f1(|_: &(), _: &()| {});
-   |            ~~~     ~~~
+   |            +       +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:3:5
@@ -35,8 +35,8 @@ LL | fn f2<F>(_: F) where F: for<'a> Fn(&'a (), &()) {}
    |                         ^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `f2`
 help: consider borrowing the argument
    |
-LL |     f2(|_: &'a (), _: &()| {});
-   |            ~~~~~~     ~~~
+LL |     f2(|_: &(), _: &()| {});
+   |            +       +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:4:5
@@ -56,7 +56,7 @@ LL | fn f3<'a, F>(_: F) where F: Fn(&'a (), &()) {}
 help: consider borrowing the argument
    |
 LL |     f3(|_: &(), _: &()| {});
-   |            ~~~     ~~~
+   |            +       +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:5:5
@@ -75,8 +75,8 @@ LL | fn f4<F>(_: F) where F: for<'r> Fn(&(), &'r ()) {}
    |                         ^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `f4`
 help: consider borrowing the argument
    |
-LL |     f4(|_: &(), _: &'r ()| {});
-   |            ~~~     ~~~~~~
+LL |     f4(|_: &(), _: &()| {});
+   |            +       +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:6:5
@@ -95,17 +95,15 @@ LL | fn f5<F>(_: F) where F: for<'r> Fn(&'r (), &'r ()) {}
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `f5`
 help: consider borrowing the argument
    |
-LL |     f5(|_: &'r (), _: &'r ()| {});
-   |            ~~~~~~     ~~~~~~
+LL |     f5(|_: &(), _: &()| {});
+   |            +       +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:7:5
    |
 LL |     g1(|_: (), _: ()| {});
-   |     ^^ --------------
-   |     |  |   |
-   |     |  |   help: consider borrowing the argument: `&()`
-   |     |  found signature defined here
+   |     ^^ -------------- found signature defined here
+   |     |
    |     expected due to this
    |
    = note: expected closure signature `for<'a> fn(&'a (), Box<(dyn for<'a> Fn(&'a ()) + 'static)>) -> _`
@@ -115,15 +113,17 @@ note: required by a bound in `g1`
    |
 LL | fn g1<F>(_: F) where F: Fn(&(), Box<dyn Fn(&())>) {}
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `g1`
+help: consider borrowing the argument
+   |
+LL |     g1(|_: &(), _: ()| {});
+   |            +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:8:5
    |
 LL |     g2(|_: (), _: ()| {});
-   |     ^^ --------------
-   |     |  |   |
-   |     |  |   help: consider borrowing the argument: `&()`
-   |     |  found signature defined here
+   |     ^^ -------------- found signature defined here
+   |     |
    |     expected due to this
    |
    = note: expected closure signature `for<'a> fn(&'a (), for<'a> fn(&'a ())) -> _`
@@ -133,15 +133,17 @@ note: required by a bound in `g2`
    |
 LL | fn g2<F>(_: F) where F: Fn(&(), fn(&())) {}
    |                         ^^^^^^^^^^^^^^^^ required by this bound in `g2`
+help: consider borrowing the argument
+   |
+LL |     g2(|_: &(), _: ()| {});
+   |            +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:9:5
    |
 LL |     g3(|_: (), _: ()| {});
-   |     ^^ --------------
-   |     |  |   |
-   |     |  |   help: consider borrowing the argument: `&'s ()`
-   |     |  found signature defined here
+   |     ^^ -------------- found signature defined here
+   |     |
    |     expected due to this
    |
    = note: expected closure signature `for<'s> fn(&'s (), Box<(dyn for<'a> Fn(&'a ()) + 'static)>) -> _`
@@ -151,15 +153,17 @@ note: required by a bound in `g3`
    |
 LL | fn g3<F>(_: F) where F: for<'s> Fn(&'s (), Box<dyn Fn(&())>) {}
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `g3`
+help: consider borrowing the argument
+   |
+LL |     g3(|_: &(), _: ()| {});
+   |            +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:10:5
    |
 LL |     g4(|_: (), _: ()| {});
-   |     ^^ --------------
-   |     |  |   |
-   |     |  |   help: consider borrowing the argument: `&()`
-   |     |  found signature defined here
+   |     ^^ -------------- found signature defined here
+   |     |
    |     expected due to this
    |
    = note: expected closure signature `for<'a> fn(&'a (), for<'r> fn(&'r ())) -> _`
@@ -169,6 +173,10 @@ note: required by a bound in `g4`
    |
 LL | fn g4<F>(_: F) where F: Fn(&(), for<'r> fn(&'r ())) {}
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `g4`
+help: consider borrowing the argument
+   |
+LL |     g4(|_: &(), _: ()| {});
+   |            +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:11:5
@@ -188,7 +196,7 @@ LL | fn h1<F>(_: F) where F: Fn(&(), Box<dyn Fn(&())>, &(), fn(&(), &())) {}
 help: consider borrowing the argument
    |
 LL |     h1(|_: &(), _: (), _: &(), _: ()| {});
-   |            ~~~            ~~~
+   |            +              +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/anonymous-higher-ranked-lifetime.rs:12:5
@@ -207,8 +215,8 @@ LL | fn h2<F>(_: F) where F: for<'t0> Fn(&(), Box<dyn Fn(&())>, &'t0 (), fn(&(),
    |                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ required by this bound in `h2`
 help: consider borrowing the argument
    |
-LL |     h2(|_: &(), _: (), _: &'t0 (), _: ()| {});
-   |            ~~~            ~~~~~~~
+LL |     h2(|_: &(), _: (), _: &(), _: ()| {});
+   |            +              +
 
 error: aborting due to 11 previous errors
 
diff --git a/tests/ui/async-await/auxiliary/issue-107036.rs b/tests/ui/async-await/auxiliary/issue-107036.rs
new file mode 100644
index 00000000000..c3f6141b284
--- /dev/null
+++ b/tests/ui/async-await/auxiliary/issue-107036.rs
@@ -0,0 +1,12 @@
+// edition:2021
+
+pub trait T {}
+impl T for () {}
+
+pub struct S {}
+
+impl S {
+    pub async fn f<'a>(&self) -> impl T + 'a {
+        ()
+    }
+}
diff --git a/tests/ui/async-await/await-sequence.rs b/tests/ui/async-await/await-sequence.rs
new file mode 100644
index 00000000000..726c4284ec1
--- /dev/null
+++ b/tests/ui/async-await/await-sequence.rs
@@ -0,0 +1,21 @@
+// edition:2021
+// compile-flags: -Z drop-tracking
+// build-pass
+
+use std::collections::HashMap;
+
+fn main() {
+    let _ = real_main();
+}
+
+async fn nop() {}
+
+async fn real_main() {
+    nop().await;
+    nop().await;
+    nop().await;
+    nop().await;
+
+    let mut map: HashMap<(), ()> = HashMap::new();
+    map.insert((), nop().await);
+}
diff --git a/tests/ui/async-await/in-trait/missing-send-bound.rs b/tests/ui/async-await/in-trait/missing-send-bound.rs
new file mode 100644
index 00000000000..78922b59b27
--- /dev/null
+++ b/tests/ui/async-await/in-trait/missing-send-bound.rs
@@ -0,0 +1,21 @@
+// edition:2021
+
+#![feature(async_fn_in_trait)]
+//~^ WARN the feature `async_fn_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+
+trait Foo {
+    async fn bar();
+}
+
+async fn test<T: Foo>() {
+    T::bar().await;
+}
+
+fn test2<T: Foo>() {
+    assert_is_send(test::<T>());
+    //~^ ERROR future cannot be sent between threads safely
+}
+
+fn assert_is_send(_: impl Send) {}
+
+fn main() {}
diff --git a/tests/ui/async-await/in-trait/missing-send-bound.stderr b/tests/ui/async-await/in-trait/missing-send-bound.stderr
new file mode 100644
index 00000000000..5cedf3ddb0f
--- /dev/null
+++ b/tests/ui/async-await/in-trait/missing-send-bound.stderr
@@ -0,0 +1,29 @@
+warning: the feature `async_fn_in_trait` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/missing-send-bound.rs:3:12
+   |
+LL | #![feature(async_fn_in_trait)]
+   |            ^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #91611 <https://github.com/rust-lang/rust/issues/91611> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error: future cannot be sent between threads safely
+  --> $DIR/missing-send-bound.rs:15:20
+   |
+LL |     assert_is_send(test::<T>());
+   |                    ^^^^^^^^^^^ future returned by `test` is not `Send`
+   |
+   = help: within `impl Future<Output = ()>`, the trait `Send` is not implemented for `impl Future<Output = ()>`
+note: future is not `Send` as it awaits another future which is not `Send`
+  --> $DIR/missing-send-bound.rs:11:5
+   |
+LL |     T::bar().await;
+   |     ^^^^^^^^ await occurs here on type `impl Future<Output = ()>`, which is not `Send`
+note: required by a bound in `assert_is_send`
+  --> $DIR/missing-send-bound.rs:19:27
+   |
+LL | fn assert_is_send(_: impl Send) {}
+   |                           ^^^^ required by this bound in `assert_is_send`
+
+error: aborting due to previous error; 1 warning emitted
+
diff --git a/tests/ui/async-await/issue-107036.rs b/tests/ui/async-await/issue-107036.rs
new file mode 100644
index 00000000000..6a22de2c943
--- /dev/null
+++ b/tests/ui/async-await/issue-107036.rs
@@ -0,0 +1,14 @@
+// aux-build:issue-107036.rs
+// edition:2021
+// check-pass
+
+extern crate issue_107036;
+use issue_107036::S;
+
+async fn f() {
+    S{}.f().await;
+}
+
+fn main() {
+    let _ = f();
+}
diff --git a/tests/ui/cast/cast-as-bool.rs b/tests/ui/cast/cast-as-bool.rs
index 1aed218aeb4..fbebc80d91c 100644
--- a/tests/ui/cast/cast-as-bool.rs
+++ b/tests/ui/cast/cast-as-bool.rs
@@ -2,8 +2,12 @@ fn main() {
     let u = 5 as bool; //~ ERROR cannot cast as `bool`
                        //~| HELP compare with zero instead
                        //~| SUGGESTION 5 != 0
+
     let t = (1 + 2) as bool; //~ ERROR cannot cast as `bool`
                              //~| HELP compare with zero instead
                              //~| SUGGESTION (1 + 2) != 0
-    let v = "hello" as bool; //~ ERROR casting `&'static str` as `bool` is invalid
+
+    let v = "hello" as bool;
+    //~^ ERROR casting `&'static str` as `bool` is invalid
+    //~| HELP consider using the `is_empty` method on `&'static str` to determine if it contains anything
 }
diff --git a/tests/ui/cast/cast-as-bool.stderr b/tests/ui/cast/cast-as-bool.stderr
index 15d94ab69d8..19ac8f10fec 100644
--- a/tests/ui/cast/cast-as-bool.stderr
+++ b/tests/ui/cast/cast-as-bool.stderr
@@ -5,16 +5,21 @@ LL |     let u = 5 as bool;
    |             ^^^^^^^^^ help: compare with zero instead: `5 != 0`
 
 error[E0054]: cannot cast as `bool`
-  --> $DIR/cast-as-bool.rs:5:13
+  --> $DIR/cast-as-bool.rs:6:13
    |
 LL |     let t = (1 + 2) as bool;
    |             ^^^^^^^^^^^^^^^ help: compare with zero instead: `(1 + 2) != 0`
 
 error[E0606]: casting `&'static str` as `bool` is invalid
-  --> $DIR/cast-as-bool.rs:8:13
+  --> $DIR/cast-as-bool.rs:10:13
    |
 LL |     let v = "hello" as bool;
    |             ^^^^^^^^^^^^^^^
+   |
+help: consider using the `is_empty` method on `&'static str` to determine if it contains anything
+   |
+LL |     let v = !"hello".is_empty();
+   |             +       ~~~~~~~~~~~
 
 error: aborting due to 3 previous errors
 
diff --git a/tests/ui/cast/issue-106883-is-empty.rs b/tests/ui/cast/issue-106883-is-empty.rs
new file mode 100644
index 00000000000..27e0816dd1c
--- /dev/null
+++ b/tests/ui/cast/issue-106883-is-empty.rs
@@ -0,0 +1,27 @@
+use std::ops::Deref;
+
+struct Foo;
+
+impl Deref for Foo {
+    type Target = [u8];
+
+    fn deref(&self) -> &Self::Target {
+        &[]
+    }
+}
+
+fn main() {
+    let _ = "foo" as bool;
+    //~^ ERROR casting `&'static str` as `bool` is invalid [E0606]
+
+    let _ = String::from("foo") as bool;
+    //~^ ERROR non-primitive cast: `String` as `bool` [E0605]
+
+    let _ = Foo as bool;
+    //~^ ERROR non-primitive cast: `Foo` as `bool` [E0605]
+}
+
+fn _slice(bar: &[i32]) -> bool {
+    bar as bool
+    //~^ ERROR casting `&[i32]` as `bool` is invalid [E0606]
+}
diff --git a/tests/ui/cast/issue-106883-is-empty.stderr b/tests/ui/cast/issue-106883-is-empty.stderr
new file mode 100644
index 00000000000..7115c7704ca
--- /dev/null
+++ b/tests/ui/cast/issue-106883-is-empty.stderr
@@ -0,0 +1,58 @@
+error[E0606]: casting `&'static str` as `bool` is invalid
+  --> $DIR/issue-106883-is-empty.rs:14:13
+   |
+LL |     let _ = "foo" as bool;
+   |             ^^^^^^^^^^^^^
+   |
+help: consider using the `is_empty` method on `&'static str` to determine if it contains anything
+   |
+LL |     let _ = !"foo".is_empty();
+   |             +     ~~~~~~~~~~~
+
+error[E0605]: non-primitive cast: `String` as `bool`
+  --> $DIR/issue-106883-is-empty.rs:17:13
+   |
+LL |     let _ = String::from("foo") as bool;
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
+   |
+note: this expression `Deref`s to `str` which implements `is_empty`
+  --> $DIR/issue-106883-is-empty.rs:17:13
+   |
+LL |     let _ = String::from("foo") as bool;
+   |             ^^^^^^^^^^^^^^^^^^^
+help: consider using the `is_empty` method on `String` to determine if it contains anything
+   |
+LL |     let _ = !String::from("foo").is_empty();
+   |             +                   ~~~~~~~~~~~
+
+error[E0605]: non-primitive cast: `Foo` as `bool`
+  --> $DIR/issue-106883-is-empty.rs:20:13
+   |
+LL |     let _ = Foo as bool;
+   |             ^^^^^^^^^^^ an `as` expression can only be used to convert between primitive types or to coerce to a specific trait object
+   |
+note: this expression `Deref`s to `[u8]` which implements `is_empty`
+  --> $DIR/issue-106883-is-empty.rs:20:13
+   |
+LL |     let _ = Foo as bool;
+   |             ^^^
+help: consider using the `is_empty` method on `Foo` to determine if it contains anything
+   |
+LL |     let _ = !Foo.is_empty();
+   |             +   ~~~~~~~~~~~
+
+error[E0606]: casting `&[i32]` as `bool` is invalid
+  --> $DIR/issue-106883-is-empty.rs:25:5
+   |
+LL |     bar as bool
+   |     ^^^^^^^^^^^
+   |
+help: consider using the `is_empty` method on `&[i32]` to determine if it contains anything
+   |
+LL |     !bar.is_empty()
+   |     +   ~~~~~~~~~~~
+
+error: aborting due to 4 previous errors
+
+Some errors have detailed explanations: E0605, E0606.
+For more information about an error, try `rustc --explain E0605`.
diff --git a/tests/ui/chalkify/bugs/async.rs b/tests/ui/chalkify/bugs/async.rs
index 1c69b07e3d4..3169e4781ee 100644
--- a/tests/ui/chalkify/bugs/async.rs
+++ b/tests/ui/chalkify/bugs/async.rs
@@ -1,7 +1,7 @@
-// check-fail
-// known-bug
+// edition:2021
+// known-bug: unknown
 // unset-rustc-env:RUST_BACKTRACE
-// compile-flags:-Z trait-solver=chalk --edition=2021
+// compile-flags:-Z trait-solver=chalk
 // error-pattern:internal compiler error
 // failure-status:101
 // normalize-stderr-test "DefId([^)]*)" -> "..."
diff --git a/tests/ui/chalkify/bugs/async.stderr b/tests/ui/chalkify/bugs/async.stderr
index d1508cb1700..8043f1e5a05 100644
--- a/tests/ui/chalkify/bugs/async.stderr
+++ b/tests/ui/chalkify/bugs/async.stderr
@@ -37,7 +37,7 @@ LL | async fn foo(x: u32) -> u32 {
    = help: the trait `Future` is not implemented for `[async fn body@$DIR/async.rs:23:29: 25:2]`
    = note: [async fn body@$DIR/async.rs:23:29: 25:2] must be a future or must implement `IntoFuture` to be awaited
 
-error: internal compiler error: projection clauses should be implied from elsewhere. obligation: `Obligation(predicate=Binder(ProjectionPredicate(AliasTy { substs: [[async fn body@$DIR/async.rs:23:29: 25:2]], def_id: ...), _use_mk_alias_ty_instead: () }, Term::Ty(u32)), []), depth=0)`
+error: internal compiler error: projection clauses should be implied from elsewhere. obligation: `Obligation(predicate=Binder(ProjectionPredicate(AliasTy { substs: [[async fn body@$DIR/async.rs:23:29: 25:2]], def_id: ...) }, Term::Ty(u32)), []), depth=0)`
   --> $DIR/async.rs:23:25
    |
 LL | async fn foo(x: u32) -> u32 {
diff --git a/tests/ui/closures/multiple-fn-bounds.stderr b/tests/ui/closures/multiple-fn-bounds.stderr
index da26302c9d8..32a1edb0024 100644
--- a/tests/ui/closures/multiple-fn-bounds.stderr
+++ b/tests/ui/closures/multiple-fn-bounds.stderr
@@ -2,10 +2,8 @@ error[E0631]: type mismatch in closure arguments
   --> $DIR/multiple-fn-bounds.rs:10:5
    |
 LL |     foo(move |x| v);
-   |     ^^^ --------
-   |     |   |     |
-   |     |   |     help: do not borrow the argument: `char`
-   |     |   found signature defined here
+   |     ^^^ -------- found signature defined here
+   |     |
    |     expected due to this
    |
    = note: expected closure signature `fn(char) -> _`
@@ -20,6 +18,10 @@ note: required by a bound in `foo`
    |
 LL | fn foo<F: Fn(&char) -> bool + Fn(char) -> bool>(f: F) {
    |                               ^^^^^^^^^^^^^^^^ required by this bound in `foo`
+help: do not borrow the argument
+   |
+LL |     foo(move |char| v);
+   |               ~~~~
 
 error: aborting due to previous error
 
diff --git a/tests/ui/coherence/coherence-with-generator.rs b/tests/ui/coherence/coherence-with-generator.rs
index 70665ba06f9..5eb8dc2a468 100644
--- a/tests/ui/coherence/coherence-with-generator.rs
+++ b/tests/ui/coherence/coherence-with-generator.rs
@@ -1,5 +1,11 @@
 // Test that encountering closures during coherence does not cause issues.
 #![feature(type_alias_impl_trait, generators)]
+#![cfg_attr(specialized, feature(specialization))]
+#![allow(incomplete_features)]
+
+// revisions: stock specialized
+// [specialized]check-pass
+
 type OpaqueGenerator = impl Sized;
 fn defining_use() -> OpaqueGenerator {
     || {
@@ -13,6 +19,6 @@ struct Wrapper<T>(T);
 trait Trait {}
 impl Trait for Wrapper<OpaqueGenerator> {}
 impl<T: Sync> Trait for Wrapper<T> {}
-//~^ ERROR conflicting implementations of trait `Trait` for type `Wrapper<OpaqueGenerator>`
+//[stock]~^ ERROR conflicting implementations of trait `Trait` for type `Wrapper<OpaqueGenerator>`
 
 fn main() {}
diff --git a/tests/ui/coherence/coherence-with-generator.stderr b/tests/ui/coherence/coherence-with-generator.stock.stderr
index 6d3be2e16c6..478ac491264 100644
--- a/tests/ui/coherence/coherence-with-generator.stderr
+++ b/tests/ui/coherence/coherence-with-generator.stock.stderr
@@ -1,5 +1,5 @@
 error[E0119]: conflicting implementations of trait `Trait` for type `Wrapper<OpaqueGenerator>`
-  --> $DIR/coherence-with-generator.rs:15:1
+  --> $DIR/coherence-with-generator.rs:21:1
    |
 LL | impl Trait for Wrapper<OpaqueGenerator> {}
    | --------------------------------------- first implementation here
diff --git a/tests/ui/const-generics/const-param-type-depends-on-const-param.min.stderr b/tests/ui/const-generics/const-param-type-depends-on-const-param.min.stderr
index a7b78b80ca5..24aa405211f 100644
--- a/tests/ui/const-generics/const-param-type-depends-on-const-param.min.stderr
+++ b/tests/ui/const-generics/const-param-type-depends-on-const-param.min.stderr
@@ -10,7 +10,7 @@ error[E0770]: the type of const parameters must not depend on other generic para
 LL | pub struct SelfDependent<const N: [u8; N]>;
    |                                        ^ the type must not depend on the parameter `N`
 
-error: `[u8; _]` is forbidden as the type of a const generic parameter
+error: `[u8; N]` is forbidden as the type of a const generic parameter
   --> $DIR/const-param-type-depends-on-const-param.rs:11:47
    |
 LL | pub struct Dependent<const N: usize, const X: [u8; N]>([(); N]);
@@ -19,7 +19,7 @@ LL | pub struct Dependent<const N: usize, const X: [u8; N]>([(); N]);
    = note: the only supported types are integers, `bool` and `char`
    = help: more complex types are supported with `#![feature(adt_const_params)]`
 
-error: `[u8; _]` is forbidden as the type of a const generic parameter
+error: `[u8; N]` is forbidden as the type of a const generic parameter
   --> $DIR/const-param-type-depends-on-const-param.rs:15:35
    |
 LL | pub struct SelfDependent<const N: [u8; N]>;
diff --git a/tests/ui/const-generics/const-param-type-depends-on-const-param.rs b/tests/ui/const-generics/const-param-type-depends-on-const-param.rs
index 9d50f9a47ff..64b2acb0362 100644
--- a/tests/ui/const-generics/const-param-type-depends-on-const-param.rs
+++ b/tests/ui/const-generics/const-param-type-depends-on-const-param.rs
@@ -10,10 +10,10 @@
 
 pub struct Dependent<const N: usize, const X: [u8; N]>([(); N]);
 //~^ ERROR: the type of const parameters must not depend on other generic parameters
-//[min]~^^ ERROR `[u8; _]` is forbidden
+//[min]~^^ ERROR `[u8; N]` is forbidden
 
 pub struct SelfDependent<const N: [u8; N]>;
 //~^ ERROR: the type of const parameters must not depend on other generic parameters
-//[min]~^^ ERROR `[u8; _]` is forbidden
+//[min]~^^ ERROR `[u8; N]` is forbidden
 
 fn main() {}
diff --git a/tests/ui/const-generics/dont-evaluate-array-len-on-err-1.stderr b/tests/ui/const-generics/dont-evaluate-array-len-on-err-1.stderr
index 68ce61bd4a3..d8eebeb0d21 100644
--- a/tests/ui/const-generics/dont-evaluate-array-len-on-err-1.stderr
+++ b/tests/ui/const-generics/dont-evaluate-array-len-on-err-1.stderr
@@ -1,8 +1,8 @@
-error[E0277]: the trait bound `[Adt; _]: Foo` is not satisfied
+error[E0277]: the trait bound `[Adt; std::mem::size_of::<Self::Assoc>()]: Foo` is not satisfied
   --> $DIR/dont-evaluate-array-len-on-err-1.rs:15:9
    |
 LL |         <[Adt; std::mem::size_of::<Self::Assoc>()] as Foo>::bar()
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `[Adt; _]`
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Foo` is not implemented for `[Adt; std::mem::size_of::<Self::Assoc>()]`
 
 error: aborting due to previous error
 
diff --git a/tests/ui/const-generics/generic_const_exprs/array-size-in-generic-struct-param.full.stderr b/tests/ui/const-generics/generic_const_exprs/array-size-in-generic-struct-param.full.stderr
index 041232e8690..1d10dfdf10c 100644
--- a/tests/ui/const-generics/generic_const_exprs/array-size-in-generic-struct-param.full.stderr
+++ b/tests/ui/const-generics/generic_const_exprs/array-size-in-generic-struct-param.full.stderr
@@ -10,7 +10,7 @@ error: overly complex generic constant
   --> $DIR/array-size-in-generic-struct-param.rs:19:15
    |
 LL |     arr: [u8; CFG.arr_size],
-   |               ^^^^^^^^^^^^ field access is not supported in generic constant
+   |               ^^^^^^^^^^^^ field access is not supported in generic constants
    |
    = help: consider moving this anonymous constant into a `const` function
    = note: this operation may be supported in the future
diff --git a/tests/ui/const-generics/generic_const_exprs/auxiliary/anon_const_non_local.rs b/tests/ui/const-generics/generic_const_exprs/auxiliary/anon_const_non_local.rs
new file mode 100644
index 00000000000..97be074933d
--- /dev/null
+++ b/tests/ui/const-generics/generic_const_exprs/auxiliary/anon_const_non_local.rs
@@ -0,0 +1,8 @@
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+
+pub struct Foo<const N: usize>;
+
+pub fn foo<const N: usize>() -> Foo<{ N + 1 }> {
+    Foo
+}
diff --git a/tests/ui/const-generics/generic_const_exprs/const-block-is-poly.rs b/tests/ui/const-generics/generic_const_exprs/const-block-is-poly.rs
new file mode 100644
index 00000000000..7332a8f03c0
--- /dev/null
+++ b/tests/ui/const-generics/generic_const_exprs/const-block-is-poly.rs
@@ -0,0 +1,11 @@
+#![feature(inline_const, generic_const_exprs)]
+//~^ WARN the feature `generic_const_exprs` is incomplete
+
+fn foo<T>() {
+    let _ = [0u8; const { std::mem::size_of::<T>() }];
+    //~^ ERROR: overly complex generic constant
+}
+
+fn main() {
+    foo::<i32>();
+}
diff --git a/tests/ui/const-generics/generic_const_exprs/const-block-is-poly.stderr b/tests/ui/const-generics/generic_const_exprs/const-block-is-poly.stderr
new file mode 100644
index 00000000000..f2625990840
--- /dev/null
+++ b/tests/ui/const-generics/generic_const_exprs/const-block-is-poly.stderr
@@ -0,0 +1,20 @@
+warning: the feature `generic_const_exprs` is incomplete and may not be safe to use and/or cause compiler crashes
+  --> $DIR/const-block-is-poly.rs:1:26
+   |
+LL | #![feature(inline_const, generic_const_exprs)]
+   |                          ^^^^^^^^^^^^^^^^^^^
+   |
+   = note: see issue #76560 <https://github.com/rust-lang/rust/issues/76560> for more information
+   = note: `#[warn(incomplete_features)]` on by default
+
+error: overly complex generic constant
+  --> $DIR/const-block-is-poly.rs:5:19
+   |
+LL |     let _ = [0u8; const { std::mem::size_of::<T>() }];
+   |                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ const blocks are not supported in generic constants
+   |
+   = help: consider moving this anonymous constant into a `const` function
+   = note: this operation may be supported in the future
+
+error: aborting due to previous error; 1 warning emitted
+
diff --git a/tests/ui/const-generics/generic_const_exprs/issue-62504.min.stderr b/tests/ui/const-generics/generic_const_exprs/issue-62504.min.stderr
index 9bea4105d58..65822856e1d 100644
--- a/tests/ui/const-generics/generic_const_exprs/issue-62504.min.stderr
+++ b/tests/ui/const-generics/generic_const_exprs/issue-62504.min.stderr
@@ -15,7 +15,7 @@ LL |         ArrayHolder([0; Self::SIZE])
    |         arguments to this struct are incorrect
    |
    = note: expected array `[u32; X]`
-              found array `[u32; _]`
+              found array `[u32; Self::SIZE]`
 note: tuple struct defined here
   --> $DIR/issue-62504.rs:14:8
    |
diff --git a/tests/ui/const-generics/generic_const_exprs/issue-79518-default_trait_method_normalization.stderr b/tests/ui/const-generics/generic_const_exprs/issue-79518-default_trait_method_normalization.stderr
index 029528c3a81..9baf9790e19 100644
--- a/tests/ui/const-generics/generic_const_exprs/issue-79518-default_trait_method_normalization.stderr
+++ b/tests/ui/const-generics/generic_const_exprs/issue-79518-default_trait_method_normalization.stderr
@@ -2,13 +2,13 @@ error[E0308]: mismatched types
   --> $DIR/issue-79518-default_trait_method_normalization.rs:16:32
    |
 LL |         Self::AssocInstance == [(); std::mem::size_of::<Self::Assoc>()];
-   |         -------------------    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected associated type, found array `[(); _]`
+   |         -------------------    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected associated type, found array `[(); std::mem::size_of::<Self::Assoc>()]`
    |         |
    |         expected because this is `<Self as Foo>::Assoc`
    |
    = note: expected associated type `<Self as Foo>::Assoc`
-                        found array `[(); _]`
-   = help: consider constraining the associated type `<Self as Foo>::Assoc` to `[(); _]` or calling a method that returns `<Self as Foo>::Assoc`
+                        found array `[(); std::mem::size_of::<Self::Assoc>()]`
+   = help: consider constraining the associated type `<Self as Foo>::Assoc` to `[(); std::mem::size_of::<Self::Assoc>()]` or calling a method that returns `<Self as Foo>::Assoc`
    = note: for more information, visit https://doc.rust-lang.org/book/ch19-03-advanced-traits.html
 
 error: aborting due to previous error
diff --git a/tests/ui/const-generics/generic_const_exprs/let-bindings.stderr b/tests/ui/const-generics/generic_const_exprs/let-bindings.stderr
index 5ebb4c3999c..823a4f8a185 100644
--- a/tests/ui/const-generics/generic_const_exprs/let-bindings.stderr
+++ b/tests/ui/const-generics/generic_const_exprs/let-bindings.stderr
@@ -2,7 +2,7 @@ error: overly complex generic constant
   --> $DIR/let-bindings.rs:6:68
    |
 LL | fn test<const N: usize>() -> [u8; { let x = N; N + 1 }] where [u8; { let x = N; N + 1 }]: Default {
-   |                                                                    ^^^^^^^^^^^^^^^^^^^^ blocks are not supported in generic constant
+   |                                                                    ^^^^^^^^^^^^^^^^^^^^ blocks are not supported in generic constants
    |
    = help: consider moving this anonymous constant into a `const` function
    = note: this operation may be supported in the future
@@ -11,7 +11,7 @@ error: overly complex generic constant
   --> $DIR/let-bindings.rs:6:35
    |
 LL | fn test<const N: usize>() -> [u8; { let x = N; N + 1 }] where [u8; { let x = N; N + 1 }]: Default {
-   |                                   ^^^^^^^^^^^^^^^^^^^^ blocks are not supported in generic constant
+   |                                   ^^^^^^^^^^^^^^^^^^^^ blocks are not supported in generic constants
    |
    = help: consider moving this anonymous constant into a `const` function
    = note: this operation may be supported in the future
diff --git a/tests/ui/const-generics/generic_const_exprs/non_local_anon_const_diagnostics.rs b/tests/ui/const-generics/generic_const_exprs/non_local_anon_const_diagnostics.rs
new file mode 100644
index 00000000000..1254b4435f7
--- /dev/null
+++ b/tests/ui/const-generics/generic_const_exprs/non_local_anon_const_diagnostics.rs
@@ -0,0 +1,16 @@
+// aux-build:anon_const_non_local.rs
+
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+
+extern crate anon_const_non_local;
+
+fn bar<const M: usize>()
+where
+    [(); M + 1]:,
+{
+    let _: anon_const_non_local::Foo<2> = anon_const_non_local::foo::<M>();
+    //~^ ERROR: mismatched types
+}
+
+fn main() {}
diff --git a/tests/ui/const-generics/generic_const_exprs/non_local_anon_const_diagnostics.stderr b/tests/ui/const-generics/generic_const_exprs/non_local_anon_const_diagnostics.stderr
new file mode 100644
index 00000000000..3926c830adb
--- /dev/null
+++ b/tests/ui/const-generics/generic_const_exprs/non_local_anon_const_diagnostics.stderr
@@ -0,0 +1,12 @@
+error[E0308]: mismatched types
+  --> $DIR/non_local_anon_const_diagnostics.rs:12:43
+   |
+LL |     let _: anon_const_non_local::Foo<2> = anon_const_non_local::foo::<M>();
+   |                                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected `2`, found `anon_const_non_local::::foo::{constant#0}`
+   |
+   = note: expected constant `2`
+              found constant `anon_const_non_local::::foo::{constant#0}`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0308`.
diff --git a/tests/ui/const-generics/generic_const_exprs/unused_expr.stderr b/tests/ui/const-generics/generic_const_exprs/unused_expr.stderr
index df73acf53de..265a3b9d233 100644
--- a/tests/ui/const-generics/generic_const_exprs/unused_expr.stderr
+++ b/tests/ui/const-generics/generic_const_exprs/unused_expr.stderr
@@ -2,7 +2,7 @@ error: overly complex generic constant
   --> $DIR/unused_expr.rs:4:34
    |
 LL | fn add<const N: usize>() -> [u8; { N + 1; 5 }] {
-   |                                  ^^^^^^^^^^^^ blocks are not supported in generic constant
+   |                                  ^^^^^^^^^^^^ blocks are not supported in generic constants
    |
    = help: consider moving this anonymous constant into a `const` function
    = note: this operation may be supported in the future
@@ -11,7 +11,7 @@ error: overly complex generic constant
   --> $DIR/unused_expr.rs:9:34
    |
 LL | fn div<const N: usize>() -> [u8; { N / 1; 5 }] {
-   |                                  ^^^^^^^^^^^^ blocks are not supported in generic constant
+   |                                  ^^^^^^^^^^^^ blocks are not supported in generic constants
    |
    = help: consider moving this anonymous constant into a `const` function
    = note: this operation may be supported in the future
@@ -20,7 +20,7 @@ error: overly complex generic constant
   --> $DIR/unused_expr.rs:16:38
    |
 LL | fn fn_call<const N: usize>() -> [u8; { foo(N); 5 }] {
-   |                                      ^^^^^^^^^^^^^ blocks are not supported in generic constant
+   |                                      ^^^^^^^^^^^^^ blocks are not supported in generic constants
    |
    = help: consider moving this anonymous constant into a `const` function
    = note: this operation may be supported in the future
diff --git a/tests/ui/const-generics/issue-106419-struct-with-multiple-const-params.rs b/tests/ui/const-generics/issue-106419-struct-with-multiple-const-params.rs
new file mode 100644
index 00000000000..8363e5af4b6
--- /dev/null
+++ b/tests/ui/const-generics/issue-106419-struct-with-multiple-const-params.rs
@@ -0,0 +1,12 @@
+// check-pass
+#![feature(generic_const_exprs)]
+#![allow(incomplete_features)]
+
+#[derive(Clone)]
+struct Bar<const A: usize, const B: usize>
+where
+    [(); A as usize]:,
+    [(); B as usize]:,
+{}
+
+fn main() {}
diff --git a/tests/ui/const-generics/issues/issue-62878.min.stderr b/tests/ui/const-generics/issues/issue-62878.min.stderr
index af029a6516b..5a721720d78 100644
--- a/tests/ui/const-generics/issues/issue-62878.min.stderr
+++ b/tests/ui/const-generics/issues/issue-62878.min.stderr
@@ -4,7 +4,7 @@ error[E0770]: the type of const parameters must not depend on other generic para
 LL | fn foo<const N: usize, const A: [u8; N]>() {}
    |                                      ^ the type must not depend on the parameter `N`
 
-error: `[u8; _]` is forbidden as the type of a const generic parameter
+error: `[u8; N]` is forbidden as the type of a const generic parameter
   --> $DIR/issue-62878.rs:5:33
    |
 LL | fn foo<const N: usize, const A: [u8; N]>() {}
diff --git a/tests/ui/const-generics/issues/issue-62878.rs b/tests/ui/const-generics/issues/issue-62878.rs
index 578ce765b2f..4c08a484ef4 100644
--- a/tests/ui/const-generics/issues/issue-62878.rs
+++ b/tests/ui/const-generics/issues/issue-62878.rs
@@ -4,7 +4,7 @@
 
 fn foo<const N: usize, const A: [u8; N]>() {}
 //~^ ERROR the type of const parameters must not
-//[min]~| ERROR `[u8; _]` is forbidden as the type of a const generic parameter
+//[min]~| ERROR `[u8; N]` is forbidden as the type of a const generic parameter
 
 fn main() {
     foo::<_, { [1] }>();
diff --git a/tests/ui/const-generics/issues/issue-67945-2.full.stderr b/tests/ui/const-generics/issues/issue-67945-2.full.stderr
index cce85772aa4..47429b7612f 100644
--- a/tests/ui/const-generics/issues/issue-67945-2.full.stderr
+++ b/tests/ui/const-generics/issues/issue-67945-2.full.stderr
@@ -8,7 +8,7 @@ LL | |         let x: Option<Box<Self>> = None;
 LL | |
 LL | |         0
 LL | |     }],
-   | |_____^ blocks are not supported in generic constant
+   | |_____^ blocks are not supported in generic constants
    |
    = help: consider moving this anonymous constant into a `const` function
    = note: this operation may be supported in the future
diff --git a/tests/ui/const-generics/issues/issue-67945-3.full.stderr b/tests/ui/const-generics/issues/issue-67945-3.full.stderr
index d3d9452d316..98f9f83976a 100644
--- a/tests/ui/const-generics/issues/issue-67945-3.full.stderr
+++ b/tests/ui/const-generics/issues/issue-67945-3.full.stderr
@@ -7,7 +7,7 @@ LL | |         let x: Option<S> = None;
 LL | |
 LL | |         0
 LL | |     }],
-   | |_____^ blocks are not supported in generic constant
+   | |_____^ blocks are not supported in generic constants
    |
    = help: consider moving this anonymous constant into a `const` function
    = note: this operation may be supported in the future
diff --git a/tests/ui/const-generics/issues/issue-67945-4.full.stderr b/tests/ui/const-generics/issues/issue-67945-4.full.stderr
index 9604eb35d02..c03d40a7bb8 100644
--- a/tests/ui/const-generics/issues/issue-67945-4.full.stderr
+++ b/tests/ui/const-generics/issues/issue-67945-4.full.stderr
@@ -7,7 +7,7 @@ LL | |         let x: Option<Box<S>> = None;
 LL | |
 LL | |         0
 LL | |     }],
-   | |_____^ blocks are not supported in generic constant
+   | |_____^ blocks are not supported in generic constants
    |
    = help: consider moving this anonymous constant into a `const` function
    = note: this operation may be supported in the future
diff --git a/tests/ui/const-generics/issues/issue-71169.min.stderr b/tests/ui/const-generics/issues/issue-71169.min.stderr
index 87ed2d4f8da..998b16a79e6 100644
--- a/tests/ui/const-generics/issues/issue-71169.min.stderr
+++ b/tests/ui/const-generics/issues/issue-71169.min.stderr
@@ -4,7 +4,7 @@ error[E0770]: the type of const parameters must not depend on other generic para
 LL | fn foo<const LEN: usize, const DATA: [u8; LEN]>() {}
    |                                           ^^^ the type must not depend on the parameter `LEN`
 
-error: `[u8; _]` is forbidden as the type of a const generic parameter
+error: `[u8; LEN]` is forbidden as the type of a const generic parameter
   --> $DIR/issue-71169.rs:5:38
    |
 LL | fn foo<const LEN: usize, const DATA: [u8; LEN]>() {}
diff --git a/tests/ui/const-generics/issues/issue-71169.rs b/tests/ui/const-generics/issues/issue-71169.rs
index 617149a8418..e4ec6b07376 100644
--- a/tests/ui/const-generics/issues/issue-71169.rs
+++ b/tests/ui/const-generics/issues/issue-71169.rs
@@ -4,7 +4,7 @@
 
 fn foo<const LEN: usize, const DATA: [u8; LEN]>() {}
 //~^ ERROR the type of const parameters must not
-//[min]~^^ ERROR `[u8; _]` is forbidden as the type of a const generic parameter
+//[min]~^^ ERROR `[u8; LEN]` is forbidden as the type of a const generic parameter
 fn main() {
     const DATA: [u8; 4] = *b"ABCD";
     foo::<4, DATA>();
diff --git a/tests/ui/const-generics/issues/issue-73491.min.stderr b/tests/ui/const-generics/issues/issue-73491.min.stderr
index f2b58e59f73..f03354fc472 100644
--- a/tests/ui/const-generics/issues/issue-73491.min.stderr
+++ b/tests/ui/const-generics/issues/issue-73491.min.stderr
@@ -1,4 +1,4 @@
-error: `[u32; _]` is forbidden as the type of a const generic parameter
+error: `[u32; LEN]` is forbidden as the type of a const generic parameter
   --> $DIR/issue-73491.rs:8:19
    |
 LL | fn hoge<const IN: [u32; LEN]>() {}
diff --git a/tests/ui/const-generics/issues/issue-73491.rs b/tests/ui/const-generics/issues/issue-73491.rs
index f15c1f2d455..482dbb04daa 100644
--- a/tests/ui/const-generics/issues/issue-73491.rs
+++ b/tests/ui/const-generics/issues/issue-73491.rs
@@ -6,6 +6,6 @@
 const LEN: usize = 1024;
 
 fn hoge<const IN: [u32; LEN]>() {}
-//[min]~^ ERROR `[u32; _]` is forbidden as the type of a const generic parameter
+//[min]~^ ERROR `[u32; LEN]` is forbidden as the type of a const generic parameter
 
 fn main() {}
diff --git a/tests/ui/const-generics/issues/issue-74101.min.stderr b/tests/ui/const-generics/issues/issue-74101.min.stderr
index 82ffb233240..134c248347d 100644
--- a/tests/ui/const-generics/issues/issue-74101.min.stderr
+++ b/tests/ui/const-generics/issues/issue-74101.min.stderr
@@ -1,4 +1,4 @@
-error: `[u8; _]` is forbidden as the type of a const generic parameter
+error: `[u8; 1 + 2]` is forbidden as the type of a const generic parameter
   --> $DIR/issue-74101.rs:6:18
    |
 LL | fn test<const N: [u8; 1 + 2]>() {}
@@ -7,7 +7,7 @@ LL | fn test<const N: [u8; 1 + 2]>() {}
    = note: the only supported types are integers, `bool` and `char`
    = help: more complex types are supported with `#![feature(adt_const_params)]`
 
-error: `[u8; _]` is forbidden as the type of a const generic parameter
+error: `[u8; 1 + 2]` is forbidden as the type of a const generic parameter
   --> $DIR/issue-74101.rs:9:21
    |
 LL | struct Foo<const N: [u8; 1 + 2]>;
diff --git a/tests/ui/const-generics/issues/issue-74101.rs b/tests/ui/const-generics/issues/issue-74101.rs
index 6b606b9460f..4c9b2d3c634 100644
--- a/tests/ui/const-generics/issues/issue-74101.rs
+++ b/tests/ui/const-generics/issues/issue-74101.rs
@@ -4,9 +4,9 @@
 #![cfg_attr(full, allow(incomplete_features))]
 
 fn test<const N: [u8; 1 + 2]>() {}
-//[min]~^ ERROR `[u8; _]` is forbidden as the type of a const generic parameter
+//[min]~^ ERROR `[u8; 1 + 2]` is forbidden as the type of a const generic parameter
 
 struct Foo<const N: [u8; 1 + 2]>;
-//[min]~^ ERROR `[u8; _]` is forbidden as the type of a const generic parameter
+//[min]~^ ERROR `[u8; 1 + 2]` is forbidden as the type of a const generic parameter
 
 fn main() {}
diff --git a/tests/ui/const-generics/issues/issue-75047.min.stderr b/tests/ui/const-generics/issues/issue-75047.min.stderr
index 7798ae79629..46af19ef395 100644
--- a/tests/ui/const-generics/issues/issue-75047.min.stderr
+++ b/tests/ui/const-generics/issues/issue-75047.min.stderr
@@ -1,4 +1,4 @@
-error: `[u8; _]` is forbidden as the type of a const generic parameter
+error: `[u8; Bar::<u32>::value()]` is forbidden as the type of a const generic parameter
   --> $DIR/issue-75047.rs:14:21
    |
 LL | struct Foo<const N: [u8; Bar::<u32>::value()]>;
diff --git a/tests/ui/const-generics/issues/issue-75047.rs b/tests/ui/const-generics/issues/issue-75047.rs
index ee3dcf9ecec..7b6fb92bca9 100644
--- a/tests/ui/const-generics/issues/issue-75047.rs
+++ b/tests/ui/const-generics/issues/issue-75047.rs
@@ -12,6 +12,6 @@ impl<T> Bar<T> {
 }
 
 struct Foo<const N: [u8; Bar::<u32>::value()]>;
-//[min]~^ ERROR `[u8; _]` is forbidden as the type of a const generic parameter
+//[min]~^ ERROR `[u8; Bar::<u32>::value()]` is forbidden as the type of a const generic parameter
 
 fn main() {}
diff --git a/tests/ui/const-generics/issues/issue-77357.stderr b/tests/ui/const-generics/issues/issue-77357.stderr
index 804c0ae5175..68b35a38b0f 100644
--- a/tests/ui/const-generics/issues/issue-77357.stderr
+++ b/tests/ui/const-generics/issues/issue-77357.stderr
@@ -2,7 +2,7 @@ error: overly complex generic constant
   --> $DIR/issue-77357.rs:6:46
    |
 LL | fn bug<'a, T>() -> &'static dyn MyTrait<[(); { |x: &'a u32| { x }; 4 }]> {
-   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^ blocks are not supported in generic constant
+   |                                              ^^^^^^^^^^^^^^^^^^^^^^^^^ blocks are not supported in generic constants
    |
    = help: consider moving this anonymous constant into a `const` function
    = note: this operation may be supported in the future
diff --git a/tests/ui/const-generics/issues/issue-85031-2.rs b/tests/ui/const-generics/issues/issue-85031-2.rs
index 4908fb29692..50dd66da6db 100644
--- a/tests/ui/const-generics/issues/issue-85031-2.rs
+++ b/tests/ui/const-generics/issues/issue-85031-2.rs
@@ -1,5 +1,5 @@
 // check-pass
-// known-bug
+// known-bug: unknown
 
 // This should not compile, as the compiler should not know
 // `A - 0` is satisfied `?x - 0` if `?x` is inferred to `A`.
@@ -10,7 +10,6 @@ pub struct Ref<'a>(&'a i32);
 
 impl<'a> Ref<'a> {
     pub fn foo<const A: usize>() -> [(); A - 0] {
-        //~^ WARN function cannot
         Self::foo()
     }
 }
diff --git a/tests/ui/const-generics/issues/issue-85031-2.stderr b/tests/ui/const-generics/issues/issue-85031-2.stderr
index fc690576875..896e1c7ea8d 100644
--- a/tests/ui/const-generics/issues/issue-85031-2.stderr
+++ b/tests/ui/const-generics/issues/issue-85031-2.stderr
@@ -3,7 +3,6 @@ warning: function cannot return without recursing
    |
 LL |     pub fn foo<const A: usize>() -> [(); A - 0] {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ cannot return without recursing
-LL |
 LL |         Self::foo()
    |         ----------- recursive call site
    |
diff --git a/tests/ui/const-generics/issues/issue-90318.rs b/tests/ui/const-generics/issues/issue-90318.rs
index d6c48e63bb3..909997340f3 100644
--- a/tests/ui/const-generics/issues/issue-90318.rs
+++ b/tests/ui/const-generics/issues/issue-90318.rs
@@ -12,14 +12,14 @@ impl True for If<true> {}
 fn consume<T: 'static>(_val: T)
 where
     If<{ TypeId::of::<T>() != TypeId::of::<()>() }>: True,
-    //~^ ERROR: can't compare
+    //~^ overly complex generic constant
 {
 }
 
 fn test<T: 'static>()
 where
     If<{ TypeId::of::<T>() != TypeId::of::<()>() }>: True,
-    //~^ ERROR: can't compare
+    //~^ overly complex generic constant
 {
 }
 
diff --git a/tests/ui/const-generics/issues/issue-90318.stderr b/tests/ui/const-generics/issues/issue-90318.stderr
index aba4b5c1a8d..f13fd795d7a 100644
--- a/tests/ui/const-generics/issues/issue-90318.stderr
+++ b/tests/ui/const-generics/issues/issue-90318.stderr
@@ -1,29 +1,24 @@
-error[E0277]: can't compare `TypeId` with `_` in const contexts
-  --> $DIR/issue-90318.rs:14:28
+error: overly complex generic constant
+  --> $DIR/issue-90318.rs:14:8
    |
 LL |     If<{ TypeId::of::<T>() != TypeId::of::<()>() }>: True,
-   |                            ^^ no implementation for `TypeId == _`
+   |        ^^-----------------^^^^^^^^^^^^^^^^^^^^^^^^
+   |          |
+   |          borrowing is not supported in generic constants
    |
-   = help: the trait `~const PartialEq<_>` is not implemented for `TypeId`
-note: the trait `PartialEq<_>` is implemented for `TypeId`, but that implementation is not `const`
-  --> $DIR/issue-90318.rs:14:28
-   |
-LL |     If<{ TypeId::of::<T>() != TypeId::of::<()>() }>: True,
-   |                            ^^
+   = help: consider moving this anonymous constant into a `const` function
+   = note: this operation may be supported in the future
 
-error[E0277]: can't compare `TypeId` with `_` in const contexts
-  --> $DIR/issue-90318.rs:21:28
+error: overly complex generic constant
+  --> $DIR/issue-90318.rs:21:8
    |
 LL |     If<{ TypeId::of::<T>() != TypeId::of::<()>() }>: True,
-   |                            ^^ no implementation for `TypeId == _`
+   |        ^^-----------------^^^^^^^^^^^^^^^^^^^^^^^^
+   |          |
+   |          borrowing is not supported in generic constants
    |
-   = help: the trait `~const PartialEq<_>` is not implemented for `TypeId`
-note: the trait `PartialEq<_>` is implemented for `TypeId`, but that implementation is not `const`
-  --> $DIR/issue-90318.rs:21:28
-   |
-LL |     If<{ TypeId::of::<T>() != TypeId::of::<()>() }>: True,
-   |                            ^^
+   = help: consider moving this anonymous constant into a `const` function
+   = note: this operation may be supported in the future
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/const-generics/nested-type.min.stderr b/tests/ui/const-generics/nested-type.min.stderr
index 276ebf31ff8..cff02b0d445 100644
--- a/tests/ui/const-generics/nested-type.min.stderr
+++ b/tests/ui/const-generics/nested-type.min.stderr
@@ -1,4 +1,14 @@
-error: `[u8; _]` is forbidden as the type of a const generic parameter
+error: `[u8; {
+           struct Foo<const N: usize>;
+       
+           impl<const N: usize> Foo<N> {
+               fn value() -> usize {
+                   N
+               }
+           }
+       
+           Foo::<17>::value()
+       }]` is forbidden as the type of a const generic parameter
   --> $DIR/nested-type.rs:6:21
    |
 LL |   struct Foo<const N: [u8; {
diff --git a/tests/ui/consts/auxiliary/closure-in-foreign-crate.rs b/tests/ui/consts/auxiliary/closure-in-foreign-crate.rs
new file mode 100644
index 00000000000..edc7fa81abb
--- /dev/null
+++ b/tests/ui/consts/auxiliary/closure-in-foreign-crate.rs
@@ -0,0 +1,8 @@
+#![crate_type = "lib"]
+#![feature(const_closures, const_trait_impl)]
+#![allow(incomplete_features)]
+
+pub const fn test() {
+    let cl = const || {};
+    cl();
+}
diff --git a/tests/ui/consts/closure-in-foreign-crate.rs b/tests/ui/consts/closure-in-foreign-crate.rs
new file mode 100644
index 00000000000..fc8f480e706
--- /dev/null
+++ b/tests/ui/consts/closure-in-foreign-crate.rs
@@ -0,0 +1,8 @@
+// aux-build:closure-in-foreign-crate.rs
+// build-pass
+
+extern crate closure_in_foreign_crate;
+
+const _: () = closure_in_foreign_crate::test();
+
+fn main() {}
diff --git a/tests/ui/consts/const-match-check.eval1.stderr b/tests/ui/consts/const-match-check.eval1.stderr
index 1caf1617e21..08fcd1deab1 100644
--- a/tests/ui/consts/const-match-check.eval1.stderr
+++ b/tests/ui/consts/const-match-check.eval1.stderr
@@ -11,6 +11,10 @@ help: you might want to use `if let` to ignore the variants that aren't matched
    |
 LL |     A = { if let 0 = 0 { todo!() } 0 },
    |           ++           ~~~~~~~~~~~
+help: alternatively, you could prepend the pattern with an underscore to define a new named variable; identifiers cannot begin with digits
+   |
+LL |     A = { let _0 = 0; 0 },
+   |               +
 
 error: aborting due to previous error
 
diff --git a/tests/ui/consts/const-match-check.eval2.stderr b/tests/ui/consts/const-match-check.eval2.stderr
index f038ba1c8ed..5d86ca4bfd1 100644
--- a/tests/ui/consts/const-match-check.eval2.stderr
+++ b/tests/ui/consts/const-match-check.eval2.stderr
@@ -11,6 +11,10 @@ help: you might want to use `if let` to ignore the variants that aren't matched
    |
 LL |     let x: [i32; { if let 0 = 0 { todo!() } 0 }] = [];
    |                    ++           ~~~~~~~~~~~
+help: alternatively, you could prepend the pattern with an underscore to define a new named variable; identifiers cannot begin with digits
+   |
+LL |     let x: [i32; { let _0 = 0; 0 }] = [];
+   |                        +
 
 error: aborting due to previous error
 
diff --git a/tests/ui/consts/const-match-check.matchck.stderr b/tests/ui/consts/const-match-check.matchck.stderr
index b1921f8a41e..c8f66bb0fc0 100644
--- a/tests/ui/consts/const-match-check.matchck.stderr
+++ b/tests/ui/consts/const-match-check.matchck.stderr
@@ -11,6 +11,10 @@ help: you might want to use `if let` to ignore the variants that aren't matched
    |
 LL | const X: i32 = { if let 0 = 0 { todo!() } 0 };
    |                  ++           ~~~~~~~~~~~
+help: alternatively, you could prepend the pattern with an underscore to define a new named variable; identifiers cannot begin with digits
+   |
+LL | const X: i32 = { let _0 = 0; 0 };
+   |                      +
 
 error[E0005]: refutable pattern in local binding
   --> $DIR/const-match-check.rs:8:23
@@ -25,6 +29,10 @@ help: you might want to use `if let` to ignore the variants that aren't matched
    |
 LL | static Y: i32 = { if let 0 = 0 { todo!() } 0 };
    |                   ++           ~~~~~~~~~~~
+help: alternatively, you could prepend the pattern with an underscore to define a new named variable; identifiers cannot begin with digits
+   |
+LL | static Y: i32 = { let _0 = 0; 0 };
+   |                       +
 
 error[E0005]: refutable pattern in local binding
   --> $DIR/const-match-check.rs:13:26
@@ -39,6 +47,10 @@ help: you might want to use `if let` to ignore the variants that aren't matched
    |
 LL |     const X: i32 = { if let 0 = 0 { todo!() } 0 };
    |                      ++           ~~~~~~~~~~~
+help: alternatively, you could prepend the pattern with an underscore to define a new named variable; identifiers cannot begin with digits
+   |
+LL |     const X: i32 = { let _0 = 0; 0 };
+   |                          +
 
 error[E0005]: refutable pattern in local binding
   --> $DIR/const-match-check.rs:19:26
@@ -53,6 +65,10 @@ help: you might want to use `if let` to ignore the variants that aren't matched
    |
 LL |     const X: i32 = { if let 0 = 0 { todo!() } 0 };
    |                      ++           ~~~~~~~~~~~
+help: alternatively, you could prepend the pattern with an underscore to define a new named variable; identifiers cannot begin with digits
+   |
+LL |     const X: i32 = { let _0 = 0; 0 };
+   |                          +
 
 error: aborting due to 4 previous errors
 
diff --git a/tests/ui/consts/const-size_of-cycle.stderr b/tests/ui/consts/const-size_of-cycle.stderr
index 46f02ce8a45..17088d9995f 100644
--- a/tests/ui/consts/const-size_of-cycle.stderr
+++ b/tests/ui/consts/const-size_of-cycle.stderr
@@ -15,8 +15,8 @@ note: ...which requires const-evaluating + checking `Foo::bytes::{constant#0}`..
 LL |     bytes: [u8; std::mem::size_of::<Foo>()]
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: ...which requires computing layout of `Foo`...
-   = note: ...which requires computing layout of `[u8; _]`...
-   = note: ...which requires normalizing `[u8; _]`...
+   = note: ...which requires computing layout of `[u8; std::mem::size_of::<Foo>()]`...
+   = note: ...which requires normalizing `[u8; std::mem::size_of::<Foo>()]`...
    = note: ...which again requires evaluating type-level constant, completing the cycle
 note: cycle used when checking that `Foo` is well-formed
   --> $DIR/const-size_of-cycle.rs:3:1
diff --git a/tests/ui/consts/const_cmp_type_id.rs b/tests/ui/consts/const_cmp_type_id.rs
new file mode 100644
index 00000000000..f10d1c24f7d
--- /dev/null
+++ b/tests/ui/consts/const_cmp_type_id.rs
@@ -0,0 +1,12 @@
+// run-pass
+#![feature(const_type_id)]
+#![feature(const_trait_impl)]
+
+use std::any::TypeId;
+
+const fn main() {
+    assert!(TypeId::of::<u8>() == TypeId::of::<u8>());
+    assert!(TypeId::of::<()>() != TypeId::of::<u8>());
+    const _A: bool = TypeId::of::<u8>() < TypeId::of::<u16>();
+    // can't assert `_A` because it is not deterministic
+}
diff --git a/tests/ui/consts/issue-44415.stderr b/tests/ui/consts/issue-44415.stderr
index 57f94f8c6ab..ec64b956dfe 100644
--- a/tests/ui/consts/issue-44415.stderr
+++ b/tests/ui/consts/issue-44415.stderr
@@ -15,8 +15,8 @@ note: ...which requires const-evaluating + checking `Foo::bytes::{constant#0}`..
 LL |     bytes: [u8; unsafe { intrinsics::size_of::<Foo>() }],
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    = note: ...which requires computing layout of `Foo`...
-   = note: ...which requires computing layout of `[u8; _]`...
-   = note: ...which requires normalizing `[u8; _]`...
+   = note: ...which requires computing layout of `[u8; unsafe { intrinsics::size_of::<Foo>() }]`...
+   = note: ...which requires normalizing `[u8; unsafe { intrinsics::size_of::<Foo>() }]`...
    = note: ...which again requires evaluating type-level constant, completing the cycle
 note: cycle used when checking that `Foo` is well-formed
   --> $DIR/issue-44415.rs:5:1
diff --git a/tests/ui/consts/issue-73976-monomorphic.rs b/tests/ui/consts/issue-73976-monomorphic.rs
index 7706a97f23b..addcc1eaab6 100644
--- a/tests/ui/consts/issue-73976-monomorphic.rs
+++ b/tests/ui/consts/issue-73976-monomorphic.rs
@@ -7,6 +7,7 @@
 
 #![feature(const_type_id)]
 #![feature(const_type_name)]
+#![feature(const_trait_impl)]
 
 use std::any::{self, TypeId};
 
@@ -17,7 +18,7 @@ impl<T: 'static> GetTypeId<T> {
 }
 
 const fn check_type_id<T: 'static>() -> bool {
-    matches!(GetTypeId::<T>::VALUE, GetTypeId::<usize>::VALUE)
+    GetTypeId::<T>::VALUE == GetTypeId::<usize>::VALUE
 }
 
 pub struct GetTypeNameLen<T>(T);
diff --git a/tests/ui/consts/too_generic_eval_ice.rs b/tests/ui/consts/too_generic_eval_ice.rs
index af494e37349..8b3f4b714e1 100644
--- a/tests/ui/consts/too_generic_eval_ice.rs
+++ b/tests/ui/consts/too_generic_eval_ice.rs
@@ -7,7 +7,7 @@ impl<A, B> Foo<A, B> {
         [5; Self::HOST_SIZE] == [6; 0]
         //~^ ERROR constant expression depends on a generic parameter
         //~| ERROR constant expression depends on a generic parameter
-        //~| ERROR can't compare `[{integer}; _]` with `[{integer}; 0]`
+        //~| ERROR can't compare `[{integer}; Self::HOST_SIZE]` with `[{integer}; 0]`
     }
 }
 
diff --git a/tests/ui/consts/too_generic_eval_ice.stderr b/tests/ui/consts/too_generic_eval_ice.stderr
index 8de61fcfb73..5af82a3e34b 100644
--- a/tests/ui/consts/too_generic_eval_ice.stderr
+++ b/tests/ui/consts/too_generic_eval_ice.stderr
@@ -14,13 +14,13 @@ LL |         [5; Self::HOST_SIZE] == [6; 0]
    |
    = note: this may fail depending on what value the parameter takes
 
-error[E0277]: can't compare `[{integer}; _]` with `[{integer}; 0]`
+error[E0277]: can't compare `[{integer}; Self::HOST_SIZE]` with `[{integer}; 0]`
   --> $DIR/too_generic_eval_ice.rs:7:30
    |
 LL |         [5; Self::HOST_SIZE] == [6; 0]
-   |                              ^^ no implementation for `[{integer}; _] == [{integer}; 0]`
+   |                              ^^ no implementation for `[{integer}; Self::HOST_SIZE] == [{integer}; 0]`
    |
-   = help: the trait `PartialEq<[{integer}; 0]>` is not implemented for `[{integer}; _]`
+   = help: the trait `PartialEq<[{integer}; 0]>` is not implemented for `[{integer}; Self::HOST_SIZE]`
    = help: the following other types implement trait `PartialEq<Rhs>`:
              <&[B] as PartialEq<[A; N]>>
              <&[T] as PartialEq<Vec<U, A>>>
diff --git a/tests/ui/debuginfo/debuginfo-type-name-layout-ice-94961-1.stderr b/tests/ui/debuginfo/debuginfo-type-name-layout-ice-94961-1.stderr
index 851dca84c3d..d5991bcf569 100644
--- a/tests/ui/debuginfo/debuginfo-type-name-layout-ice-94961-1.stderr
+++ b/tests/ui/debuginfo/debuginfo-type-name-layout-ice-94961-1.stderr
@@ -1,4 +1,4 @@
-error: values of the type `[u8; SIZE]` are too big for the current architecture
+error: values of the type `[u8; usize::MAX]` are too big for the current architecture
 
 error: aborting due to previous error
 
diff --git a/tests/ui/debuginfo/debuginfo-type-name-layout-ice-94961-2.stderr b/tests/ui/debuginfo/debuginfo-type-name-layout-ice-94961-2.stderr
index 851dca84c3d..d5991bcf569 100644
--- a/tests/ui/debuginfo/debuginfo-type-name-layout-ice-94961-2.stderr
+++ b/tests/ui/debuginfo/debuginfo-type-name-layout-ice-94961-2.stderr
@@ -1,4 +1,4 @@
-error: values of the type `[u8; SIZE]` are too big for the current architecture
+error: values of the type `[u8; usize::MAX]` are too big for the current architecture
 
 error: aborting due to previous error
 
diff --git a/tests/ui/dep-graph/dep-graph-dump.rs b/tests/ui/dep-graph/dep-graph-dump.rs
new file mode 100644
index 00000000000..cbc4def0e03
--- /dev/null
+++ b/tests/ui/dep-graph/dep-graph-dump.rs
@@ -0,0 +1,6 @@
+// Test dump-dep-graph requires query-dep-graph enabled
+
+// incremental
+// compile-flags: -Z dump-dep-graph
+
+fn main() {}
diff --git a/tests/ui/dep-graph/dep-graph-dump.stderr b/tests/ui/dep-graph/dep-graph-dump.stderr
new file mode 100644
index 00000000000..ea44b8bb075
--- /dev/null
+++ b/tests/ui/dep-graph/dep-graph-dump.stderr
@@ -0,0 +1,2 @@
+error: can't dump dependency graph without `-Z query-dep-graph`
+
diff --git a/tests/ui/deriving/deriving-all-codegen.stdout b/tests/ui/deriving/deriving-all-codegen.stdout
index a63cbd4ca7e..e6ee11a783b 100644
--- a/tests/ui/deriving/deriving-all-codegen.stdout
+++ b/tests/ui/deriving/deriving-all-codegen.stdout
@@ -731,11 +731,12 @@ impl ::core::marker::Copy for Fieldless { }
 #[automatically_derived]
 impl ::core::fmt::Debug for Fieldless {
     fn fmt(&self, f: &mut ::core::fmt::Formatter) -> ::core::fmt::Result {
-        match self {
-            Fieldless::A => ::core::fmt::Formatter::write_str(f, "A"),
-            Fieldless::B => ::core::fmt::Formatter::write_str(f, "B"),
-            Fieldless::C => ::core::fmt::Formatter::write_str(f, "C"),
-        }
+        ::core::fmt::Formatter::write_str(f,
+            match self {
+                Fieldless::A => "A",
+                Fieldless::B => "B",
+                Fieldless::C => "C",
+            })
     }
 }
 #[automatically_derived]
diff --git a/tests/ui/empty/empty-macro-use.stderr b/tests/ui/empty/empty-macro-use.stderr
index 700f6616af4..e0b3b8685d6 100644
--- a/tests/ui/empty/empty-macro-use.stderr
+++ b/tests/ui/empty/empty-macro-use.stderr
@@ -4,7 +4,7 @@ error: cannot find macro `macro_two` in this scope
 LL |     macro_two!();
    |     ^^^^^^^^^
    |
-   = note: consider importing this macro:
+   = help: consider importing this macro:
            two_macros::macro_two
 
 error: aborting due to previous error
diff --git a/tests/ui/error-codes/E0208.rs b/tests/ui/error-codes/E0208.rs
new file mode 100644
index 00000000000..c67d42889d6
--- /dev/null
+++ b/tests/ui/error-codes/E0208.rs
@@ -0,0 +1,8 @@
+#![feature(rustc_attrs)]
+
+#[rustc_variance]
+struct Foo<'a, T> { //~ ERROR [-, o]
+    t: &'a mut T,
+}
+
+fn main() {}
diff --git a/tests/ui/error-codes/E0208.stderr b/tests/ui/error-codes/E0208.stderr
new file mode 100644
index 00000000000..dbbb41e7950
--- /dev/null
+++ b/tests/ui/error-codes/E0208.stderr
@@ -0,0 +1,8 @@
+error: [-, o]
+  --> $DIR/E0208.rs:4:1
+   |
+LL | struct Foo<'a, T> {
+   | ^^^^^^^^^^^^^^^^^
+
+error: aborting due to previous error
+
diff --git a/tests/ui/error-codes/E0606.rs b/tests/ui/error-codes/E0606.rs
index cb0d8cfc31e..6f6c6513846 100644
--- a/tests/ui/error-codes/E0606.rs
+++ b/tests/ui/error-codes/E0606.rs
@@ -1,3 +1,4 @@
 fn main() {
-    &0u8 as u8; //~ ERROR E0606
+    let x = &(&0u8 as u8); //~ ERROR E0606
+    x as u8; //~ casting `&u8` as `u8` is invalid [E0606]
 }
diff --git a/tests/ui/error-codes/E0606.stderr b/tests/ui/error-codes/E0606.stderr
index fce24886eb0..2492eb299cc 100644
--- a/tests/ui/error-codes/E0606.stderr
+++ b/tests/ui/error-codes/E0606.stderr
@@ -1,12 +1,26 @@
 error[E0606]: casting `&u8` as `u8` is invalid
-  --> $DIR/E0606.rs:2:5
+  --> $DIR/E0606.rs:2:14
    |
-LL |     &0u8 as u8;
-   |     ----^^^^^^
-   |     |
-   |     cannot cast `&u8` as `u8`
-   |     help: dereference the expression: `*&0u8`
+LL |     let x = &(&0u8 as u8);
+   |              ^^^^^^^^^^^^
+   |
+help: remove the unneeded borrow
+   |
+LL -     let x = &(&0u8 as u8);
+LL +     let x = &(0u8 as u8);
+   |
+
+error[E0606]: casting `&u8` as `u8` is invalid
+  --> $DIR/E0606.rs:3:5
+   |
+LL |     x as u8;
+   |     ^^^^^^^
+   |
+help: dereference the expression
+   |
+LL |     *x as u8;
+   |     +
 
-error: aborting due to previous error
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0606`.
diff --git a/tests/ui/error-festival.stderr b/tests/ui/error-festival.stderr
index fe9956b70bd..e8ee1d96942 100644
--- a/tests/ui/error-festival.stderr
+++ b/tests/ui/error-festival.stderr
@@ -69,10 +69,12 @@ error[E0606]: casting `&u8` as `u32` is invalid
   --> $DIR/error-festival.rs:37:18
    |
 LL |     let y: u32 = x as u32;
-   |                  -^^^^^^^
-   |                  |
-   |                  cannot cast `&u8` as `u32`
-   |                  help: dereference the expression: `*x`
+   |                  ^^^^^^^^
+   |
+help: dereference the expression
+   |
+LL |     let y: u32 = *x as u32;
+   |                  +
 
 error[E0607]: cannot cast thin pointer `*const u8` to fat pointer `*const [u8]`
   --> $DIR/error-festival.rs:41:5
diff --git a/tests/ui/errors/auxiliary/remapped_dep.rs b/tests/ui/errors/auxiliary/remapped_dep.rs
new file mode 100644
index 00000000000..f9bb7bf8987
--- /dev/null
+++ b/tests/ui/errors/auxiliary/remapped_dep.rs
@@ -0,0 +1,4 @@
+// compile-flags: --remap-path-prefix={{src-base}}/errors/auxiliary=remapped-aux
+// no-remap-src-base: Manually remap, so the remapped path remains in .stderr file.
+
+pub struct SomeStruct {} // This line should be show as part of the error.
diff --git a/tests/ui/errors/remap-path-prefix-reverse.local-self.stderr b/tests/ui/errors/remap-path-prefix-reverse.local-self.stderr
new file mode 100644
index 00000000000..51e3b776cb2
--- /dev/null
+++ b/tests/ui/errors/remap-path-prefix-reverse.local-self.stderr
@@ -0,0 +1,14 @@
+error[E0423]: expected value, found struct `remapped_dep::SomeStruct`
+  --> $DIR/remap-path-prefix-reverse.rs:16:13
+   |
+LL |     let _ = remapped_dep::SomeStruct; // ~ERROR E0423
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: use struct literal syntax instead: `remapped_dep::SomeStruct {}`
+   |
+  ::: remapped-aux/remapped_dep.rs:4:1
+   |
+LL | pub struct SomeStruct {} // This line should be show as part of the error.
+   | --------------------- `remapped_dep::SomeStruct` defined here
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0423`.
diff --git a/tests/ui/errors/remap-path-prefix-reverse.remapped-self.stderr b/tests/ui/errors/remap-path-prefix-reverse.remapped-self.stderr
new file mode 100644
index 00000000000..51e3b776cb2
--- /dev/null
+++ b/tests/ui/errors/remap-path-prefix-reverse.remapped-self.stderr
@@ -0,0 +1,14 @@
+error[E0423]: expected value, found struct `remapped_dep::SomeStruct`
+  --> $DIR/remap-path-prefix-reverse.rs:16:13
+   |
+LL |     let _ = remapped_dep::SomeStruct; // ~ERROR E0423
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^ help: use struct literal syntax instead: `remapped_dep::SomeStruct {}`
+   |
+  ::: remapped-aux/remapped_dep.rs:4:1
+   |
+LL | pub struct SomeStruct {} // This line should be show as part of the error.
+   | --------------------- `remapped_dep::SomeStruct` defined here
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0423`.
diff --git a/tests/ui/errors/remap-path-prefix-reverse.rs b/tests/ui/errors/remap-path-prefix-reverse.rs
new file mode 100644
index 00000000000..71c80063c32
--- /dev/null
+++ b/tests/ui/errors/remap-path-prefix-reverse.rs
@@ -0,0 +1,17 @@
+// aux-build:remapped_dep.rs
+// compile-flags: --remap-path-prefix={{src-base}}/errors/auxiliary=remapped-aux
+
+// revisions: local-self remapped-self
+// [local-self] no-remap-src-base: The hack should work regardless of remapping.
+// [remapped-self] remap-src-base
+
+// Verify that the expected source code is shown.
+// error-pattern: pub struct SomeStruct {} // This line should be show
+
+extern crate remapped_dep;
+
+fn main() {
+    // The actual error is irrelevant. The important part it that is should show
+    // a snippet of the dependency's source.
+    let _ = remapped_dep::SomeStruct; // ~ERROR E0423
+}
diff --git a/tests/ui/remap-path-prefix.rs b/tests/ui/errors/remap-path-prefix.rs
index 2eef9709977..393b8e22f1c 100644
--- a/tests/ui/remap-path-prefix.rs
+++ b/tests/ui/errors/remap-path-prefix.rs
@@ -1,4 +1,12 @@
 // compile-flags: --remap-path-prefix={{src-base}}=remapped
+// no-remap-src-base: Manually remap, so the remapped path remains in .stderr file.
+
+// The remapped paths are not normalized by compiletest.
+// normalize-stderr-test: "\\(errors)" -> "/$1"
+
+// The remapped paths aren't recognized by compiletest, so we
+// cannot use line-specific patterns.
+// error-pattern: E0425
 
 fn main() {
     // We cannot actually put an ERROR marker here because
diff --git a/tests/ui/remap-path-prefix.stderr b/tests/ui/errors/remap-path-prefix.stderr
index ad6a35d1256..62dbd4b8881 100644
--- a/tests/ui/remap-path-prefix.stderr
+++ b/tests/ui/errors/remap-path-prefix.stderr
@@ -1,5 +1,5 @@
 error[E0425]: cannot find value `ferris` in this scope
-  --> remapped/remap-path-prefix.rs:8:5
+  --> remapped/errors/remap-path-prefix.rs:16:5
    |
 LL |     ferris
    |     ^^^^^^ not found in this scope
diff --git a/tests/ui/extenv/issue-55897.stderr b/tests/ui/extenv/issue-55897.stderr
index 63797d4a71b..92e8a44b55f 100644
--- a/tests/ui/extenv/issue-55897.stderr
+++ b/tests/ui/extenv/issue-55897.stderr
@@ -30,7 +30,7 @@ LL |     use env;
 help: consider importing this module instead
    |
 LL |     use std::env;
-   |         ~~~~~~~~~
+   |         ~~~~~~~~
 
 error: cannot determine resolution for the macro `env`
   --> $DIR/issue-55897.rs:6:22
diff --git a/tests/ui/fmt/auxiliary/format-string-proc-macro.rs b/tests/ui/fmt/auxiliary/format-string-proc-macro.rs
index 539c8fb27b3..1b7ef93f41d 100644
--- a/tests/ui/fmt/auxiliary/format-string-proc-macro.rs
+++ b/tests/ui/fmt/auxiliary/format-string-proc-macro.rs
@@ -28,6 +28,7 @@ pub fn err_with_input_span(input: TokenStream) -> TokenStream {
     TokenStream::from(TokenTree::Literal(lit))
 }
 
+
 #[proc_macro]
 pub fn respan_to_invalid_format_literal(input: TokenStream) -> TokenStream {
     let mut s = Literal::string("{");
@@ -38,3 +39,14 @@ pub fn respan_to_invalid_format_literal(input: TokenStream) -> TokenStream {
         TokenTree::from(Group::new(Delimiter::Parenthesis, TokenTree::from(s).into())),
     ])
 }
+
+#[proc_macro]
+pub fn capture_a_with_prepended_space_preserve_span(input: TokenStream) -> TokenStream {
+    let mut s = Literal::string(" {a}");
+    s.set_span(input.into_iter().next().unwrap().span());
+    TokenStream::from_iter([
+        TokenTree::from(Ident::new("format", Span::call_site())),
+        TokenTree::from(Punct::new('!', Spacing::Alone)),
+        TokenTree::from(Group::new(Delimiter::Parenthesis, TokenTree::from(s).into())),
+    ])
+}
diff --git a/tests/ui/fmt/indoc-issue-106408.rs b/tests/ui/fmt/indoc-issue-106408.rs
new file mode 100644
index 00000000000..e4e3093b590
--- /dev/null
+++ b/tests/ui/fmt/indoc-issue-106408.rs
@@ -0,0 +1,9 @@
+// aux-build:format-string-proc-macro.rs
+// check-pass
+
+extern crate format_string_proc_macro;
+
+fn main() {
+    let a = 0;
+    format_string_proc_macro::capture_a_with_prepended_space_preserve_span!("{a}");
+}
diff --git a/tests/ui/fmt/respanned-literal-issue-106191.rs b/tests/ui/fmt/respanned-literal-issue-106191.rs
index 44642a10fc0..bb741c0ef93 100644
--- a/tests/ui/fmt/respanned-literal-issue-106191.rs
+++ b/tests/ui/fmt/respanned-literal-issue-106191.rs
@@ -1,10 +1,15 @@
 // aux-build:format-string-proc-macro.rs
+// check-fail
+// known-bug: #106191
+// unset-rustc-env:RUST_BACKTRACE
+// had to be reverted
+// error-pattern:internal compiler error
+// failure-status:101
+// dont-check-compiler-stderr
 
 extern crate format_string_proc_macro;
 
 fn main() {
     format_string_proc_macro::respan_to_invalid_format_literal!("¡");
-    //~^ ERROR invalid format string: expected `'}'` but string was terminated
     format_args!(r#concat!("¡        {"));
-    //~^ ERROR invalid format string: expected `'}'` but string was terminated
 }
diff --git a/tests/ui/fmt/respanned-literal-issue-106191.stderr b/tests/ui/fmt/respanned-literal-issue-106191.stderr
index 73a3af65a38..16717f42253 100644
--- a/tests/ui/fmt/respanned-literal-issue-106191.stderr
+++ b/tests/ui/fmt/respanned-literal-issue-106191.stderr
@@ -1,19 +1,2 @@
-error: invalid format string: expected `'}'` but string was terminated
-  --> $DIR/respanned-literal-issue-106191.rs:6:65
-   |
-LL |     format_string_proc_macro::respan_to_invalid_format_literal!("¡");
-   |                                                                 ^^^ expected `'}'` in format string
-   |
-   = note: if you intended to print `{`, you can escape it using `{{`
-
-error: invalid format string: expected `'}'` but string was terminated
-  --> $DIR/respanned-literal-issue-106191.rs:8:18
-   |
-LL |     format_args!(r#concat!("¡        {"));
-   |                  ^^^^^^^^^^^^^^^^^^^^^^^ expected `'}'` in format string
-   |
-   = note: if you intended to print `{`, you can escape it using `{{`
-   = note: this error originates in the macro `concat` (in Nightly builds, run with -Z macro-backtrace for more info)
-
-error: aborting due to 2 previous errors
-
+                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  query stack during panic:
+end of query stack
diff --git a/tests/ui/generic-associated-types/bugs/hrtb-implied-1.rs b/tests/ui/generic-associated-types/bugs/hrtb-implied-1.rs
index 719d1bd5a4c..5101de19d3c 100644
--- a/tests/ui/generic-associated-types/bugs/hrtb-implied-1.rs
+++ b/tests/ui/generic-associated-types/bugs/hrtb-implied-1.rs
@@ -1,5 +1,5 @@
 // check-fail
-// known-bug
+// known-bug: unknown
 
 // This gives us problems because `for<'a> I::Item<'a>: Debug` should mean "for
 // all 'a where I::Item<'a> is WF", but really means "for all 'a possible"
@@ -29,7 +29,6 @@ where
 
 fn main() {
     let slice = &mut ();
-    //~^ temporary value dropped while borrowed
     let windows = WindowsMut { slice };
     print_items::<WindowsMut<'_>>(windows);
 }
diff --git a/tests/ui/generic-associated-types/bugs/hrtb-implied-1.stderr b/tests/ui/generic-associated-types/bugs/hrtb-implied-1.stderr
index 1c9abc4e837..362aeae2361 100644
--- a/tests/ui/generic-associated-types/bugs/hrtb-implied-1.stderr
+++ b/tests/ui/generic-associated-types/bugs/hrtb-implied-1.stderr
@@ -3,7 +3,7 @@ error[E0716]: temporary value dropped while borrowed
    |
 LL |     let slice = &mut ();
    |                      ^^ creates a temporary value which is freed while still in use
-...
+LL |     let windows = WindowsMut { slice };
 LL |     print_items::<WindowsMut<'_>>(windows);
    |     -------------------------------------- argument requires that borrow lasts for `'static`
 LL | }
diff --git a/tests/ui/generic-associated-types/bugs/hrtb-implied-2.rs b/tests/ui/generic-associated-types/bugs/hrtb-implied-2.rs
index 8e6c5348e71..3174227a7a1 100644
--- a/tests/ui/generic-associated-types/bugs/hrtb-implied-2.rs
+++ b/tests/ui/generic-associated-types/bugs/hrtb-implied-2.rs
@@ -1,5 +1,5 @@
 // check-fail
-// known-bug
+// known-bug: unknown
 
 // This gives us problems because `for<'a> I::Item<'a>: Debug` should mean "for
 // all 'a where I::Item<'a> is WF", but really means "for all 'a possible"
@@ -16,7 +16,6 @@ where
 {
     let mut iter2 = Eat(iter, f);
     let _next = iter2.next();
-    //~^ borrowed data escapes
     true
 }
 impl<I: LendingIterator> LendingIterator for &mut I {
diff --git a/tests/ui/generic-associated-types/bugs/issue-100013.rs b/tests/ui/generic-associated-types/bugs/issue-100013.rs
index fc4e47a3ba1..973c548d785 100644
--- a/tests/ui/generic-associated-types/bugs/issue-100013.rs
+++ b/tests/ui/generic-associated-types/bugs/issue-100013.rs
@@ -1,5 +1,5 @@
 // check-fail
-// known-bug
+// known-bug: unknown
 // edition: 2021
 
 // We really should accept this, but we need implied bounds between the regions
@@ -13,7 +13,6 @@ pub trait FutureIterator {
 
 fn call<I: FutureIterator>() -> impl Send {
     async { // a generator checked for autotrait impl `Send`
-        //~^ lifetime bound not satisfied
         let x = None::<I::Future<'_, '_>>; // a type referencing GAT
         async {}.await; // a yield point
     }
@@ -21,16 +20,13 @@ fn call<I: FutureIterator>() -> impl Send {
 
 fn call2<'a, 'b, I: FutureIterator>() -> impl Send {
     async { // a generator checked for autotrait impl `Send`
-        //~^ lifetime bound not satisfied
         let x = None::<I::Future<'a, 'b>>; // a type referencing GAT
-        //~^ lifetime may not live long enough
         async {}.await; // a yield point
     }
 }
 
 fn call3<'a: 'b, 'b, I: FutureIterator>() -> impl Send {
     async { // a generator checked for autotrait impl `Send`
-        //~^ lifetime bound not satisfied
         let x = None::<I::Future<'a, 'b>>; // a type referencing GAT
         async {}.await; // a yield point
     }
diff --git a/tests/ui/generic-associated-types/bugs/issue-100013.stderr b/tests/ui/generic-associated-types/bugs/issue-100013.stderr
index 72ae288dcab..9db124a81e4 100644
--- a/tests/ui/generic-associated-types/bugs/issue-100013.stderr
+++ b/tests/ui/generic-associated-types/bugs/issue-100013.stderr
@@ -2,77 +2,73 @@ error: lifetime bound not satisfied
   --> $DIR/issue-100013.rs:15:5
    |
 LL | /     async { // a generator checked for autotrait impl `Send`
-LL | |
 LL | |         let x = None::<I::Future<'_, '_>>; // a type referencing GAT
 LL | |         async {}.await; // a yield point
 LL | |     }
    | |_____^
    |
 note: the lifetime defined here...
-  --> $DIR/issue-100013.rs:17:38
+  --> $DIR/issue-100013.rs:16:38
    |
 LL |         let x = None::<I::Future<'_, '_>>; // a type referencing GAT
    |                                      ^^
 note: ...must outlive the lifetime defined here
-  --> $DIR/issue-100013.rs:17:34
+  --> $DIR/issue-100013.rs:16:34
    |
 LL |         let x = None::<I::Future<'_, '_>>; // a type referencing GAT
    |                                  ^^
    = note: this is a known limitation that will be removed in the future (see issue #100013 <https://github.com/rust-lang/rust/issues/100013> for more information)
 
 error: lifetime bound not satisfied
-  --> $DIR/issue-100013.rs:23:5
+  --> $DIR/issue-100013.rs:22:5
    |
 LL | /     async { // a generator checked for autotrait impl `Send`
-LL | |
 LL | |         let x = None::<I::Future<'a, 'b>>; // a type referencing GAT
-LL | |
 LL | |         async {}.await; // a yield point
 LL | |     }
    | |_____^
    |
 note: the lifetime defined here...
-  --> $DIR/issue-100013.rs:22:14
+  --> $DIR/issue-100013.rs:21:14
    |
 LL | fn call2<'a, 'b, I: FutureIterator>() -> impl Send {
    |              ^^
 note: ...must outlive the lifetime defined here
-  --> $DIR/issue-100013.rs:22:10
+  --> $DIR/issue-100013.rs:21:10
    |
 LL | fn call2<'a, 'b, I: FutureIterator>() -> impl Send {
    |          ^^
    = note: this is a known limitation that will be removed in the future (see issue #100013 <https://github.com/rust-lang/rust/issues/100013> for more information)
 
 error: lifetime may not live long enough
-  --> $DIR/issue-100013.rs:25:17
+  --> $DIR/issue-100013.rs:23:17
    |
 LL | fn call2<'a, 'b, I: FutureIterator>() -> impl Send {
    |          --  -- lifetime `'b` defined here
    |          |
    |          lifetime `'a` defined here
-...
+LL |     async { // a generator checked for autotrait impl `Send`
 LL |         let x = None::<I::Future<'a, 'b>>; // a type referencing GAT
    |                 ^^^^^^^^^^^^^^^^^^^^^^^^^ requires that `'a` must outlive `'b`
    |
    = help: consider adding the following bound: `'a: 'b`
 
 error: lifetime bound not satisfied
-  --> $DIR/issue-100013.rs:32:5
+  --> $DIR/issue-100013.rs:29:5
    |
 LL | /     async { // a generator checked for autotrait impl `Send`
-LL | |
 LL | |         let x = None::<I::Future<'a, 'b>>; // a type referencing GAT
 LL | |         async {}.await; // a yield point
 LL | |     }
    | |_____^
    |
 note: the lifetime defined here...
-  --> $DIR/issue-100013.rs:31:18
+  --> $DIR/issue-100013.rs:28:18
    |
 LL | fn call3<'a: 'b, 'b, I: FutureIterator>() -> impl Send {
    |                  ^^
 note: ...must outlive the lifetime defined here
-  --> $DIR/issue-100013.rs:31:10
+  --> $DIR/issue-100013.rs:28:10
    |
 LL | fn call3<'a: 'b, 'b, I: FutureIterator>() -> impl Send {
    |          ^^
diff --git a/tests/ui/generic-associated-types/bugs/issue-91762.rs b/tests/ui/generic-associated-types/bugs/issue-91762.rs
index dec668bec10..8f2cc45509f 100644
--- a/tests/ui/generic-associated-types/bugs/issue-91762.rs
+++ b/tests/ui/generic-associated-types/bugs/issue-91762.rs
@@ -1,5 +1,5 @@
 // check-fail
-// known-bug
+// known-bug: unknown
 
 // We almost certainly want this to pass, but
 // it's particularly difficult currently, because we need a way of specifying
@@ -22,7 +22,6 @@ pub trait FunctorExt<T>: Sized {
 
         arg = self;
         ret = <Self::Base as Functor>::fmap(arg);
-        //~^ type annotations needed
     }
 }
 
diff --git a/tests/ui/generic-associated-types/collectivity-regression.stderr b/tests/ui/generic-associated-types/collectivity-regression.stderr
index 1dbe1e2cb22..a085096e1f8 100644
--- a/tests/ui/generic-associated-types/collectivity-regression.stderr
+++ b/tests/ui/generic-associated-types/collectivity-regression.stderr
@@ -9,6 +9,16 @@ LL | |         // probably should work.
 LL | |         let _x = x;
 LL | |     };
    | |_____^
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/collectivity-regression.rs:11:16
+   |
+LL |     for<'a> T: Get<Value<'a> = ()>,
+   |                ^^^^^^^^^^^^^^^^^^^
+help: consider restricting the type parameter to the `'static` lifetime
+   |
+LL |     for<'a> T: Get<Value<'a> = ()> + 'static,
+   |                                    +++++++++
 
 error: aborting due to previous error
 
diff --git a/tests/ui/generics/issue-106694.rs b/tests/ui/generics/issue-106694.rs
new file mode 100644
index 00000000000..c4b02ee81ec
--- /dev/null
+++ b/tests/ui/generics/issue-106694.rs
@@ -0,0 +1,24 @@
+trait Trait {}
+
+fn foo(_: impl &Trait) {}
+//~^ ERROR expected a trait, found type
+
+fn bar<T: &Trait>(_: T) {}
+//~^ ERROR expected a trait, found type
+
+fn partially_correct_impl(_: impl &*const &Trait + Copy) {}
+//~^ ERROR expected a trait, found type
+
+fn foo_bad(_: impl &BadTrait) {}
+//~^ ERROR expected a trait, found type
+//~^^ ERROR cannot find trait `BadTrait` in this scope
+
+fn bar_bad<T: &BadTrait>(_: T) {}
+//~^ ERROR expected a trait, found type
+//~^^ ERROR cannot find trait `BadTrait` in this scope
+
+fn partially_correct_impl_bad(_: impl &*const &BadTrait + Copy) {}
+//~^ ERROR expected a trait, found type
+//~^^ ERROR cannot find trait `BadTrait` in this scope
+
+fn main() {}
diff --git a/tests/ui/generics/issue-106694.stderr b/tests/ui/generics/issue-106694.stderr
new file mode 100644
index 00000000000..235b8982a99
--- /dev/null
+++ b/tests/ui/generics/issue-106694.stderr
@@ -0,0 +1,93 @@
+error: expected a trait, found type
+  --> $DIR/issue-106694.rs:3:16
+   |
+LL | fn foo(_: impl &Trait) {}
+   |                ^^^^^^
+   |
+help: consider removing the indirection
+   |
+LL - fn foo(_: impl &Trait) {}
+LL + fn foo(_: impl Trait) {}
+   |
+
+error: expected a trait, found type
+  --> $DIR/issue-106694.rs:6:11
+   |
+LL | fn bar<T: &Trait>(_: T) {}
+   |           ^^^^^^
+   |
+help: consider removing the indirection
+   |
+LL - fn bar<T: &Trait>(_: T) {}
+LL + fn bar<T: Trait>(_: T) {}
+   |
+
+error: expected a trait, found type
+  --> $DIR/issue-106694.rs:9:35
+   |
+LL | fn partially_correct_impl(_: impl &*const &Trait + Copy) {}
+   |                                   ^^^^^^^^^^^^^^
+   |
+help: consider removing the indirection
+   |
+LL - fn partially_correct_impl(_: impl &*const &Trait + Copy) {}
+LL + fn partially_correct_impl(_: impl Trait + Copy) {}
+   |
+
+error: expected a trait, found type
+  --> $DIR/issue-106694.rs:12:20
+   |
+LL | fn foo_bad(_: impl &BadTrait) {}
+   |                    ^^^^^^^^^
+   |
+help: consider removing the indirection
+   |
+LL - fn foo_bad(_: impl &BadTrait) {}
+LL + fn foo_bad(_: impl BadTrait) {}
+   |
+
+error: expected a trait, found type
+  --> $DIR/issue-106694.rs:16:15
+   |
+LL | fn bar_bad<T: &BadTrait>(_: T) {}
+   |               ^^^^^^^^^
+   |
+help: consider removing the indirection
+   |
+LL - fn bar_bad<T: &BadTrait>(_: T) {}
+LL + fn bar_bad<T: BadTrait>(_: T) {}
+   |
+
+error: expected a trait, found type
+  --> $DIR/issue-106694.rs:20:39
+   |
+LL | fn partially_correct_impl_bad(_: impl &*const &BadTrait + Copy) {}
+   |                                       ^^^^^^^^^^^^^^^^^
+   |
+help: consider removing the indirection
+   |
+LL - fn partially_correct_impl_bad(_: impl &*const &BadTrait + Copy) {}
+LL + fn partially_correct_impl_bad(_: impl BadTrait + Copy) {}
+   |
+
+error[E0405]: cannot find trait `BadTrait` in this scope
+  --> $DIR/issue-106694.rs:12:21
+   |
+LL | fn foo_bad(_: impl &BadTrait) {}
+   |                     ^^^^^^^^ not found in this scope
+
+error[E0405]: cannot find trait `BadTrait` in this scope
+  --> $DIR/issue-106694.rs:16:16
+   |
+LL | fn bar_bad<T: &BadTrait>(_: T) {}
+   |                ^^^^^^^^ not found in this scope
+
+error[E0405]: cannot find trait `BadTrait` in this scope
+  --> $DIR/issue-106694.rs:20:48
+   |
+LL | fn partially_correct_impl_bad(_: impl &*const &BadTrait + Copy) {}
+   |                                                ^^^^^^^^ not found in this scope
+
+error: aborting due to 9 previous errors
+
+For more information about this error, try `rustc --explain E0405`.
diff --git a/tests/ui/hygiene/globs.stderr b/tests/ui/hygiene/globs.stderr
index 1f2a96a4c41..c01901be5fe 100644
--- a/tests/ui/hygiene/globs.stderr
+++ b/tests/ui/hygiene/globs.stderr
@@ -51,7 +51,7 @@ LL | n!(f);
 LL |         n!(f);
    |            ^ not found in this scope
    |
-   = note: consider importing this function:
+   = help: consider importing this function:
            foo::f
    = note: this error originates in the macro `n` (in Nightly builds, run with -Z macro-backtrace for more info)
 
@@ -64,7 +64,7 @@ LL | n!(f);
 LL |                 f
    |                 ^ not found in this scope
    |
-   = note: consider importing this function:
+   = help: consider importing this function:
            foo::f
    = note: this error originates in the macro `n` (in Nightly builds, run with -Z macro-backtrace for more info)
 
diff --git a/tests/ui/hygiene/no_implicit_prelude-2018.stderr b/tests/ui/hygiene/no_implicit_prelude-2018.stderr
index 02ddc391f6e..3f31b041b62 100644
--- a/tests/ui/hygiene/no_implicit_prelude-2018.stderr
+++ b/tests/ui/hygiene/no_implicit_prelude-2018.stderr
@@ -4,7 +4,7 @@ error: cannot find macro `print` in this scope
 LL |         print!();
    |         ^^^^^
    |
-   = note: consider importing this macro:
+   = help: consider importing this macro:
            std::print
 
 error: aborting due to previous error
diff --git a/tests/ui/impl-trait/issues/issue-105826.rs b/tests/ui/impl-trait/issues/issue-105826.rs
new file mode 100644
index 00000000000..06dc2d4c8d3
--- /dev/null
+++ b/tests/ui/impl-trait/issues/issue-105826.rs
@@ -0,0 +1,39 @@
+// check-pass
+
+use std::io::Write;
+
+struct A(Vec<u8>);
+
+struct B<'a> {
+    one: &'a mut A,
+    two: &'a mut Vec<u8>,
+    three: Vec<u8>,
+}
+
+impl<'a> B<'a> {
+    fn one(&mut self) -> &mut impl Write {
+        &mut self.one.0
+    }
+    fn two(&mut self) -> &mut impl Write {
+        &mut *self.two
+    }
+    fn three(&mut self) -> &mut impl Write {
+        &mut self.three
+    }
+}
+
+struct C<'a>(B<'a>);
+
+impl<'a> C<'a> {
+    fn one(&mut self) -> &mut impl Write {
+        self.0.one()
+    }
+    fn two(&mut self) -> &mut impl Write {
+        self.0.two()
+    }
+    fn three(&mut self) -> &mut impl Write {
+        self.0.three()
+    }
+}
+
+fn main() {}
diff --git a/tests/ui/impl-trait/recursive-generator.rs b/tests/ui/impl-trait/recursive-generator.rs
new file mode 100644
index 00000000000..e876f0fb43f
--- /dev/null
+++ b/tests/ui/impl-trait/recursive-generator.rs
@@ -0,0 +1,23 @@
+#![feature(generators, generator_trait)]
+
+use std::ops::{Generator, GeneratorState};
+
+fn foo() -> impl Generator<Yield = (), Return = ()> {
+    //~^ ERROR cannot resolve opaque type
+    //~| NOTE recursive opaque type
+    //~| NOTE in this expansion of desugaring of
+    || {
+    //~^ NOTE returning here
+        let mut gen = Box::pin(foo());
+        //~^ NOTE generator captures itself here
+        let mut r = gen.as_mut().resume(());
+        while let GeneratorState::Yielded(v) = r {
+            yield v;
+            r = gen.as_mut().resume(());
+        }
+    }
+}
+
+fn main() {
+    foo();
+}
diff --git a/tests/ui/impl-trait/recursive-generator.stderr b/tests/ui/impl-trait/recursive-generator.stderr
new file mode 100644
index 00000000000..e23fd4b4a85
--- /dev/null
+++ b/tests/ui/impl-trait/recursive-generator.stderr
@@ -0,0 +1,19 @@
+error[E0720]: cannot resolve opaque type
+  --> $DIR/recursive-generator.rs:5:13
+   |
+LL |   fn foo() -> impl Generator<Yield = (), Return = ()> {
+   |               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ recursive opaque type
+...
+LL | /     || {
+LL | |
+LL | |         let mut gen = Box::pin(foo());
+   | |             ------- generator captures itself here
+LL | |
+...  |
+LL | |         }
+LL | |     }
+   | |_____- returning here with type `[generator@$DIR/recursive-generator.rs:9:5: 9:7]`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0720`.
diff --git a/tests/ui/impl-trait/recursive-impl-trait-type-indirect.stderr b/tests/ui/impl-trait/recursive-impl-trait-type-indirect.stderr
index 2e34d3d4275..ebb231ae14f 100644
--- a/tests/ui/impl-trait/recursive-impl-trait-type-indirect.stderr
+++ b/tests/ui/impl-trait/recursive-impl-trait-type-indirect.stderr
@@ -53,6 +53,7 @@ LL |   fn closure_capture() -> impl Sized {
 ...
 LL | /     move || {
 LL | |         x;
+   | |         - closure captures itself here
 LL | |     }
    | |_____- returning here with type `[closure@$DIR/recursive-impl-trait-type-indirect.rs:35:5: 35:12]`
 
@@ -64,6 +65,7 @@ LL |   fn closure_ref_capture() -> impl Sized {
 ...
 LL | /     move || {
 LL | |         &x;
+   | |          - closure captures itself here
 LL | |     }
    | |_____- returning here with type `[closure@$DIR/recursive-impl-trait-type-indirect.rs:43:5: 43:12]`
 
@@ -94,6 +96,7 @@ LL |   fn generator_capture() -> impl Sized {
 LL | /     move || {
 LL | |         yield;
 LL | |         x;
+   | |         - generator captures itself here
 LL | |     }
    | |_____- returning here with type `[generator@$DIR/recursive-impl-trait-type-indirect.rs:61:5: 61:12]`
 
@@ -114,6 +117,7 @@ LL |   fn generator_hold() -> impl Sized {
 LL |
 LL | /     move || {
 LL | |         let x = generator_hold();
+   | |             - generator captures itself here
 LL | |         yield;
 LL | |         x;
 LL | |     }
diff --git a/tests/ui/imports/bad-import-in-nested.stderr b/tests/ui/imports/bad-import-in-nested.stderr
index 855b1e637e9..b6b1bc5fccf 100644
--- a/tests/ui/imports/bad-import-in-nested.stderr
+++ b/tests/ui/imports/bad-import-in-nested.stderr
@@ -4,7 +4,7 @@ error[E0432]: unresolved import `super::super::C::D::AA`
 LL |         use super::{super::C::D::AA, AA as _};
    |                     ^^^^^^^^^^^^^^^ no `AA` in `C::D`
    |
-   = note: consider importing this type alias instead:
+   = help: consider importing this type alias instead:
            crate::A::AA
 
 error[E0432]: unresolved import `crate::C::AA`
@@ -13,7 +13,7 @@ error[E0432]: unresolved import `crate::C::AA`
 LL |     use crate::C::{self, AA};
    |                          ^^ no `AA` in `C`
    |
-   = note: consider importing this type alias instead:
+   = help: consider importing this type alias instead:
            crate::A::AA
 
 error[E0432]: unresolved import `crate::C::BB`
@@ -22,7 +22,7 @@ error[E0432]: unresolved import `crate::C::BB`
 LL |     use crate::{A, C::BB};
    |                    ^^^^^ no `BB` in `C`
    |
-   = note: consider importing this type alias instead:
+   = help: consider importing this type alias instead:
            crate::A::BB
 
 error: aborting due to 3 previous errors
diff --git a/tests/ui/imports/bad-import-with-rename.stderr b/tests/ui/imports/bad-import-with-rename.stderr
index cace2a7a51c..f9c5cf920e1 100644
--- a/tests/ui/imports/bad-import-with-rename.stderr
+++ b/tests/ui/imports/bad-import-with-rename.stderr
@@ -7,7 +7,7 @@ LL |     use crate::D::B as _;
 help: consider importing this type alias instead
    |
 LL |     use A::B as _;
-   |         ~~~~~~~~~~
+   |         ~~~~~~~~~
 
 error[E0432]: unresolved import `crate::D::B2`
   --> $DIR/bad-import-with-rename.rs:10:9
@@ -18,7 +18,7 @@ LL |     use crate::D::B2;
 help: consider importing this type alias instead
    |
 LL |     use A::B2;
-   |         ~~~~~~
+   |         ~~~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/imports/issue-56125.stderr b/tests/ui/imports/issue-56125.stderr
index 059ca96808d..3448f311977 100644
--- a/tests/ui/imports/issue-56125.stderr
+++ b/tests/ui/imports/issue-56125.stderr
@@ -7,13 +7,13 @@ LL |     use empty::issue_56125;
 help: consider importing one of these items instead
    |
 LL |     use crate::m3::last_segment::issue_56125;
-   |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 LL |     use crate::m3::non_last_segment::non_last_segment::issue_56125;
-   |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 LL |     use issue_56125::issue_56125;
-   |         ~~~~~~~~~~~~~~~~~~~~~~~~~
+   |         ~~~~~~~~~~~~~~~~~~~~~~~~
 LL |     use issue_56125::last_segment::issue_56125;
-   |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+   |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
      and 1 other candidate
 
 error[E0659]: `issue_56125` is ambiguous
diff --git a/tests/ui/imports/issue-57015.stderr b/tests/ui/imports/issue-57015.stderr
index 3b72d57fee4..5374ba3dc9e 100644
--- a/tests/ui/imports/issue-57015.stderr
+++ b/tests/ui/imports/issue-57015.stderr
@@ -7,7 +7,7 @@ LL | use single_err::something;
 help: consider importing this module instead
    |
 LL | use glob_ok::something;
-   |     ~~~~~~~~~~~~~~~~~~~
+   |     ~~~~~~~~~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/tests/ui/imports/issue-99695-b.fixed b/tests/ui/imports/issue-99695-b.fixed
new file mode 100644
index 00000000000..0e60c73b67a
--- /dev/null
+++ b/tests/ui/imports/issue-99695-b.fixed
@@ -0,0 +1,20 @@
+// run-rustfix
+#![allow(unused, nonstandard_style)]
+mod m {
+
+    mod p {
+        #[macro_export]
+        macro_rules! nu {
+            {} => {};
+        }
+
+        pub struct other_item;
+    }
+
+    use ::nu;
+pub use self::p::{other_item as _};
+    //~^ ERROR unresolved import `self::p::nu` [E0432]
+    //~| HELP a macro with this name exists at the root of the crate
+}
+
+fn main() {}
diff --git a/tests/ui/imports/issue-99695-b.rs b/tests/ui/imports/issue-99695-b.rs
new file mode 100644
index 00000000000..031443a1f5d
--- /dev/null
+++ b/tests/ui/imports/issue-99695-b.rs
@@ -0,0 +1,19 @@
+// run-rustfix
+#![allow(unused, nonstandard_style)]
+mod m {
+
+    mod p {
+        #[macro_export]
+        macro_rules! nu {
+            {} => {};
+        }
+
+        pub struct other_item;
+    }
+
+    pub use self::p::{nu, other_item as _};
+    //~^ ERROR unresolved import `self::p::nu` [E0432]
+    //~| HELP a macro with this name exists at the root of the crate
+}
+
+fn main() {}
diff --git a/tests/ui/imports/issue-99695-b.stderr b/tests/ui/imports/issue-99695-b.stderr
new file mode 100644
index 00000000000..b6f5c726a5c
--- /dev/null
+++ b/tests/ui/imports/issue-99695-b.stderr
@@ -0,0 +1,16 @@
+error[E0432]: unresolved import `self::p::nu`
+  --> $DIR/issue-99695-b.rs:14:23
+   |
+LL |     pub use self::p::{nu, other_item as _};
+   |                       ^^ no `nu` in `m::p`
+   |
+   = note: this could be because a macro annotated with `#[macro_export]` will be exported at the root of the crate instead of the module where it is defined
+help: a macro with this name exists at the root of the crate
+   |
+LL ~     use ::nu;
+LL ~ pub use self::p::{other_item as _};
+   |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0432`.
diff --git a/tests/ui/imports/issue-99695.fixed b/tests/ui/imports/issue-99695.fixed
new file mode 100644
index 00000000000..6bf228b23aa
--- /dev/null
+++ b/tests/ui/imports/issue-99695.fixed
@@ -0,0 +1,17 @@
+// run-rustfix
+#![allow(unused, nonstandard_style)]
+mod m {
+    #[macro_export]
+    macro_rules! nu {
+        {} => {};
+    }
+
+    pub struct other_item;
+
+    use ::nu;
+pub use self::{other_item as _};
+    //~^ ERROR unresolved import `self::nu` [E0432]
+    //~| HELP a macro with this name exists at the root of the crate
+}
+
+fn main() {}
diff --git a/tests/ui/imports/issue-99695.rs b/tests/ui/imports/issue-99695.rs
new file mode 100644
index 00000000000..f7199f1497a
--- /dev/null
+++ b/tests/ui/imports/issue-99695.rs
@@ -0,0 +1,16 @@
+// run-rustfix
+#![allow(unused, nonstandard_style)]
+mod m {
+    #[macro_export]
+    macro_rules! nu {
+        {} => {};
+    }
+
+    pub struct other_item;
+
+    pub use self::{nu, other_item as _};
+    //~^ ERROR unresolved import `self::nu` [E0432]
+    //~| HELP a macro with this name exists at the root of the crate
+}
+
+fn main() {}
diff --git a/tests/ui/imports/issue-99695.stderr b/tests/ui/imports/issue-99695.stderr
new file mode 100644
index 00000000000..0ef762e1c82
--- /dev/null
+++ b/tests/ui/imports/issue-99695.stderr
@@ -0,0 +1,16 @@
+error[E0432]: unresolved import `self::nu`
+  --> $DIR/issue-99695.rs:11:20
+   |
+LL |     pub use self::{nu, other_item as _};
+   |                    ^^ no `nu` in `m`
+   |
+   = note: this could be because a macro annotated with `#[macro_export]` will be exported at the root of the crate instead of the module where it is defined
+help: a macro with this name exists at the root of the crate
+   |
+LL ~     use ::nu;
+LL ~ pub use self::{other_item as _};
+   |
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0432`.
diff --git a/tests/ui/inference/issue-107090.rs b/tests/ui/inference/issue-107090.rs
new file mode 100644
index 00000000000..9426445656f
--- /dev/null
+++ b/tests/ui/inference/issue-107090.rs
@@ -0,0 +1,31 @@
+use std::marker::PhantomData;
+struct Foo<'a, 'b, T>(PhantomData<(&'a (), &'b (), T)>)
+where
+    Foo<'short, 'out, T>: Convert<'a, 'b>;
+    //~^ ERROR mismatched types
+    //~^^ ERROR mismatched types
+    //~^^^ ERROR use of undeclared lifetime name
+    //~| ERROR use of undeclared lifetime name `'out`
+
+trait Convert<'a, 'b>: Sized {
+    fn cast(&'a self) -> &'b Self;
+}
+impl<'long: 'short, 'short, T> Convert<'long, 'b> for Foo<'short, 'out, T> {
+    //~^ ERROR use of undeclared lifetime name
+    //~^^ ERROR use of undeclared lifetime name `'out`
+    //~| ERROR cannot infer an appropriate lifetime for lifetime parameter
+    fn cast(&'long self) -> &'short Foo<'short, 'out, T> {
+        //~^ ERROR use of undeclared lifetime name
+        //~| ERROR cannot infer an appropriate lifetime for lifetime parameter
+        self
+    }
+}
+
+fn badboi<'in_, 'out, T>(x: Foo<'in_, 'out, T>, sadness: &'in_ Foo<'short, 'out, T>) -> &'out T {
+    //~^ ERROR use of undeclared lifetime name
+    //~^^ ERROR incompatible lifetime on type
+    //~| ERROR `x` has lifetime `'in_` but it needs to satisfy a `'static` lifetime requirement
+    sadness.cast()
+}
+
+fn main() {}
diff --git a/tests/ui/inference/issue-107090.stderr b/tests/ui/inference/issue-107090.stderr
new file mode 100644
index 00000000000..33cb39014ac
--- /dev/null
+++ b/tests/ui/inference/issue-107090.stderr
@@ -0,0 +1,173 @@
+error[E0261]: use of undeclared lifetime name `'short`
+  --> $DIR/issue-107090.rs:4:9
+   |
+LL |     Foo<'short, 'out, T>: Convert<'a, 'b>;
+   |         ^^^^^^ undeclared lifetime
+   |
+   = note: for more information on higher-ranked polymorphism, visit https://doc.rust-lang.org/nomicon/hrtb.html
+help: consider making the bound lifetime-generic with a new `'short` lifetime
+   |
+LL |     for<'short> Foo<'short, 'out, T>: Convert<'a, 'b>;
+   |     +++++++++++
+help: consider introducing lifetime `'short` here
+   |
+LL | struct Foo<'short, 'a, 'b, T>(PhantomData<(&'a (), &'b (), T)>)
+   |            +++++++
+
+error[E0261]: use of undeclared lifetime name `'out`
+  --> $DIR/issue-107090.rs:4:17
+   |
+LL |     Foo<'short, 'out, T>: Convert<'a, 'b>;
+   |                 ^^^^ undeclared lifetime
+   |
+help: consider making the bound lifetime-generic with a new `'out` lifetime
+   |
+LL |     for<'out> Foo<'short, 'out, T>: Convert<'a, 'b>;
+   |     +++++++++
+help: consider introducing lifetime `'out` here
+   |
+LL | struct Foo<'out, 'a, 'b, T>(PhantomData<(&'a (), &'b (), T)>)
+   |            +++++
+
+error[E0261]: use of undeclared lifetime name `'b`
+  --> $DIR/issue-107090.rs:13:47
+   |
+LL | impl<'long: 'short, 'short, T> Convert<'long, 'b> for Foo<'short, 'out, T> {
+   |      -                                        ^^ undeclared lifetime
+   |      |
+   |      help: consider introducing lifetime `'b` here: `'b,`
+
+error[E0261]: use of undeclared lifetime name `'out`
+  --> $DIR/issue-107090.rs:13:67
+   |
+LL | impl<'long: 'short, 'short, T> Convert<'long, 'b> for Foo<'short, 'out, T> {
+   |      - help: consider introducing lifetime `'out` here: `'out,`   ^^^^ undeclared lifetime
+
+error[E0261]: use of undeclared lifetime name `'out`
+  --> $DIR/issue-107090.rs:17:49
+   |
+LL |     fn cast(&'long self) -> &'short Foo<'short, 'out, T> {
+   |                                                 ^^^^ undeclared lifetime
+   |
+help: consider introducing lifetime `'out` here
+   |
+LL |     fn cast<'out>(&'long self) -> &'short Foo<'short, 'out, T> {
+   |            ++++++
+help: consider introducing lifetime `'out` here
+   |
+LL | impl<'out, 'long: 'short, 'short, T> Convert<'long, 'b> for Foo<'short, 'out, T> {
+   |      +++++
+
+error[E0261]: use of undeclared lifetime name `'short`
+  --> $DIR/issue-107090.rs:24:68
+   |
+LL | fn badboi<'in_, 'out, T>(x: Foo<'in_, 'out, T>, sadness: &'in_ Foo<'short, 'out, T>) -> &'out T {
+   |           -                                                        ^^^^^^ undeclared lifetime
+   |           |
+   |           help: consider introducing lifetime `'short` here: `'short,`
+
+error[E0308]: mismatched types
+  --> $DIR/issue-107090.rs:4:27
+   |
+LL |     Foo<'short, 'out, T>: Convert<'a, 'b>;
+   |                           ^^^^^^^^^^^^^^^ lifetime mismatch
+   |
+   = note: expected trait `Convert<'static, 'static>`
+              found trait `Convert<'a, 'b>`
+note: the lifetime `'a` as defined here...
+  --> $DIR/issue-107090.rs:2:12
+   |
+LL | struct Foo<'a, 'b, T>(PhantomData<(&'a (), &'b (), T)>)
+   |            ^^
+   = note: ...does not necessarily outlive the static lifetime
+
+error[E0308]: mismatched types
+  --> $DIR/issue-107090.rs:4:27
+   |
+LL |     Foo<'short, 'out, T>: Convert<'a, 'b>;
+   |                           ^^^^^^^^^^^^^^^ lifetime mismatch
+   |
+   = note: expected trait `Convert<'static, 'static>`
+              found trait `Convert<'a, 'b>`
+note: the lifetime `'b` as defined here...
+  --> $DIR/issue-107090.rs:2:16
+   |
+LL | struct Foo<'a, 'b, T>(PhantomData<(&'a (), &'b (), T)>)
+   |                ^^
+   = note: ...does not necessarily outlive the static lifetime
+
+error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'long` due to conflicting requirements
+  --> $DIR/issue-107090.rs:13:55
+   |
+LL | impl<'long: 'short, 'short, T> Convert<'long, 'b> for Foo<'short, 'out, T> {
+   |                                                       ^^^^^^^^^^^^^^^^^^^^
+   |
+note: first, the lifetime cannot outlive the lifetime `'short` as defined here...
+  --> $DIR/issue-107090.rs:13:21
+   |
+LL | impl<'long: 'short, 'short, T> Convert<'long, 'b> for Foo<'short, 'out, T> {
+   |                     ^^^^^^
+   = note: ...but the lifetime must also be valid for the static lifetime...
+note: ...so that the types are compatible
+  --> $DIR/issue-107090.rs:13:55
+   |
+LL | impl<'long: 'short, 'short, T> Convert<'long, 'b> for Foo<'short, 'out, T> {
+   |                                                       ^^^^^^^^^^^^^^^^^^^^
+   = note: expected `Convert<'short, 'static>`
+              found `Convert<'_, 'static>`
+
+error: incompatible lifetime on type
+  --> $DIR/issue-107090.rs:24:29
+   |
+LL | fn badboi<'in_, 'out, T>(x: Foo<'in_, 'out, T>, sadness: &'in_ Foo<'short, 'out, T>) -> &'out T {
+   |                             ^^^^^^^^^^^^^^^^^^
+   |
+note: because this has an unmet lifetime requirement
+  --> $DIR/issue-107090.rs:4:27
+   |
+LL |     Foo<'short, 'out, T>: Convert<'a, 'b>;
+   |                           ^^^^^^^^^^^^^^^ introduces a `'static` lifetime requirement
+note: the lifetime `'out` as defined here...
+  --> $DIR/issue-107090.rs:24:17
+   |
+LL | fn badboi<'in_, 'out, T>(x: Foo<'in_, 'out, T>, sadness: &'in_ Foo<'short, 'out, T>) -> &'out T {
+   |                 ^^^^
+note: ...does not necessarily outlive the static lifetime introduced by the compatible `impl`
+  --> $DIR/issue-107090.rs:13:1
+   |
+LL | impl<'long: 'short, 'short, T> Convert<'long, 'b> for Foo<'short, 'out, T> {
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0759]: `x` has lifetime `'in_` but it needs to satisfy a `'static` lifetime requirement
+  --> $DIR/issue-107090.rs:24:29
+   |
+LL | fn badboi<'in_, 'out, T>(x: Foo<'in_, 'out, T>, sadness: &'in_ Foo<'short, 'out, T>) -> &'out T {
+   |                             ^^^^^^^^^^^^^^^^^^
+   |                             |
+   |                             this data with lifetime `'in_`...
+   |                             ...is used and required to live as long as `'static` here
+
+error[E0495]: cannot infer an appropriate lifetime for lifetime parameter `'long` due to conflicting requirements
+  --> $DIR/issue-107090.rs:17:13
+   |
+LL |     fn cast(&'long self) -> &'short Foo<'short, 'out, T> {
+   |             ^^^^^^^^^^^
+   |
+note: first, the lifetime cannot outlive the lifetime `'short` as defined here...
+  --> $DIR/issue-107090.rs:13:21
+   |
+LL | impl<'long: 'short, 'short, T> Convert<'long, 'b> for Foo<'short, 'out, T> {
+   |                     ^^^^^^
+   = note: ...but the lifetime must also be valid for the static lifetime...
+note: ...so that the types are compatible
+  --> $DIR/issue-107090.rs:17:13
+   |
+LL |     fn cast(&'long self) -> &'short Foo<'short, 'out, T> {
+   |             ^^^^^^^^^^^
+   = note: expected `Convert<'short, 'static>`
+              found `Convert<'_, 'static>`
+
+error: aborting due to 12 previous errors
+
+Some errors have detailed explanations: E0261, E0308, E0495, E0759.
+For more information about an error, try `rustc --explain E0261`.
diff --git a/tests/ui/inference/issue-83606.rs b/tests/ui/inference/issue-83606.rs
index eaaef3463dd..c387046e910 100644
--- a/tests/ui/inference/issue-83606.rs
+++ b/tests/ui/inference/issue-83606.rs
@@ -6,5 +6,5 @@ fn foo<const N: usize>(_: impl std::fmt::Display) -> [usize; N] {
 
 fn main() {
     let _ = foo("foo");
-    //~^ ERROR: type annotations needed for `[usize; _]`
+    //~^ ERROR: type annotations needed for `[usize; N]`
 }
diff --git a/tests/ui/inference/issue-83606.stderr b/tests/ui/inference/issue-83606.stderr
index f5c84f96064..f2ee8692e38 100644
--- a/tests/ui/inference/issue-83606.stderr
+++ b/tests/ui/inference/issue-83606.stderr
@@ -1,4 +1,4 @@
-error[E0282]: type annotations needed for `[usize; _]`
+error[E0282]: type annotations needed for `[usize; N]`
   --> $DIR/issue-83606.rs:8:9
    |
 LL |     let _ = foo("foo");
@@ -6,7 +6,7 @@ LL |     let _ = foo("foo");
    |
 help: consider giving this pattern a type, where the the value of const parameter `N` is specified
    |
-LL |     let _: [usize; _] = foo("foo");
+LL |     let _: [usize; N] = foo("foo");
    |          ++++++++++++
 
 error: aborting due to previous error
diff --git a/tests/ui/issues/issue-19100.fixed b/tests/ui/issues/issue-19100.fixed
index 6dc8f7ddbc9..029855de2de 100644
--- a/tests/ui/issues/issue-19100.fixed
+++ b/tests/ui/issues/issue-19100.fixed
@@ -1,4 +1,3 @@
-// run-pass
 // run-rustfix
 
 #![allow(non_snake_case)]
@@ -16,11 +15,11 @@ impl Foo {
         match self {
             &
 Foo::Bar if true
-//~^ WARN pattern binding `Bar` is named the same as one of the variants of the type `Foo`
+//~^ ERROR pattern binding `Bar` is named the same as one of the variants of the type `Foo`
 => println!("bar"),
             &
 Foo::Baz if false
-//~^ WARN pattern binding `Baz` is named the same as one of the variants of the type `Foo`
+//~^ ERROR pattern binding `Baz` is named the same as one of the variants of the type `Foo`
 => println!("baz"),
 _ => ()
         }
diff --git a/tests/ui/issues/issue-19100.rs b/tests/ui/issues/issue-19100.rs
index cfdc7c9e754..bd9e4ea5b60 100644
--- a/tests/ui/issues/issue-19100.rs
+++ b/tests/ui/issues/issue-19100.rs
@@ -1,4 +1,3 @@
-// run-pass
 // run-rustfix
 
 #![allow(non_snake_case)]
@@ -16,11 +15,11 @@ impl Foo {
         match self {
             &
 Bar if true
-//~^ WARN pattern binding `Bar` is named the same as one of the variants of the type `Foo`
+//~^ ERROR pattern binding `Bar` is named the same as one of the variants of the type `Foo`
 => println!("bar"),
             &
 Baz if false
-//~^ WARN pattern binding `Baz` is named the same as one of the variants of the type `Foo`
+//~^ ERROR pattern binding `Baz` is named the same as one of the variants of the type `Foo`
 => println!("baz"),
 _ => ()
         }
diff --git a/tests/ui/issues/issue-19100.stderr b/tests/ui/issues/issue-19100.stderr
index 293430691dd..ebbf083b7de 100644
--- a/tests/ui/issues/issue-19100.stderr
+++ b/tests/ui/issues/issue-19100.stderr
@@ -1,17 +1,17 @@
-warning[E0170]: pattern binding `Bar` is named the same as one of the variants of the type `Foo`
-  --> $DIR/issue-19100.rs:18:1
+error[E0170]: pattern binding `Bar` is named the same as one of the variants of the type `Foo`
+  --> $DIR/issue-19100.rs:17:1
    |
 LL | Bar if true
    | ^^^ help: to match on the variant, qualify the path: `Foo::Bar`
    |
-   = note: `#[warn(bindings_with_variant_name)]` on by default
+   = note: `#[deny(bindings_with_variant_name)]` on by default
 
-warning[E0170]: pattern binding `Baz` is named the same as one of the variants of the type `Foo`
-  --> $DIR/issue-19100.rs:22:1
+error[E0170]: pattern binding `Baz` is named the same as one of the variants of the type `Foo`
+  --> $DIR/issue-19100.rs:21:1
    |
 LL | Baz if false
    | ^^^ help: to match on the variant, qualify the path: `Foo::Baz`
 
-warning: 2 warnings emitted
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0170`.
diff --git a/tests/ui/issues/issue-65634-raw-ident-suggestion.stderr b/tests/ui/issues/issue-65634-raw-ident-suggestion.edition2015.stderr
index 68ccf5cab5b..d0cb16995af 100644
--- a/tests/ui/issues/issue-65634-raw-ident-suggestion.stderr
+++ b/tests/ui/issues/issue-65634-raw-ident-suggestion.edition2015.stderr
@@ -1,16 +1,16 @@
 error[E0034]: multiple applicable items in scope
-  --> $DIR/issue-65634-raw-ident-suggestion.rs:21:13
+  --> $DIR/issue-65634-raw-ident-suggestion.rs:24:13
    |
 LL |     r#fn {}.r#struct();
    |             ^^^^^^^^ multiple `r#struct` found
    |
-note: candidate #1 is defined in an impl of the trait `async` for the type `fn`
-  --> $DIR/issue-65634-raw-ident-suggestion.rs:4:5
+note: candidate #1 is defined in an impl of the trait `async` for the type `r#fn`
+  --> $DIR/issue-65634-raw-ident-suggestion.rs:7:5
    |
 LL |     fn r#struct(&self) {
    |     ^^^^^^^^^^^^^^^^^^
-note: candidate #2 is defined in an impl of the trait `await` for the type `fn`
-  --> $DIR/issue-65634-raw-ident-suggestion.rs:10:5
+note: candidate #2 is defined in an impl of the trait `await` for the type `r#fn`
+  --> $DIR/issue-65634-raw-ident-suggestion.rs:13:5
    |
 LL |     fn r#struct(&self) {
    |     ^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/issues/issue-65634-raw-ident-suggestion.edition2018.stderr b/tests/ui/issues/issue-65634-raw-ident-suggestion.edition2018.stderr
new file mode 100644
index 00000000000..a75c1c41363
--- /dev/null
+++ b/tests/ui/issues/issue-65634-raw-ident-suggestion.edition2018.stderr
@@ -0,0 +1,28 @@
+error[E0034]: multiple applicable items in scope
+  --> $DIR/issue-65634-raw-ident-suggestion.rs:24:13
+   |
+LL |     r#fn {}.r#struct();
+   |             ^^^^^^^^ multiple `r#struct` found
+   |
+note: candidate #1 is defined in an impl of the trait `r#async` for the type `r#fn`
+  --> $DIR/issue-65634-raw-ident-suggestion.rs:7:5
+   |
+LL |     fn r#struct(&self) {
+   |     ^^^^^^^^^^^^^^^^^^
+note: candidate #2 is defined in an impl of the trait `r#await` for the type `r#fn`
+  --> $DIR/issue-65634-raw-ident-suggestion.rs:13:5
+   |
+LL |     fn r#struct(&self) {
+   |     ^^^^^^^^^^^^^^^^^^
+help: disambiguate the associated function for candidate #1
+   |
+LL |     r#async::r#struct(&r#fn {});
+   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+help: disambiguate the associated function for candidate #2
+   |
+LL |     r#await::r#struct(&r#fn {});
+   |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0034`.
diff --git a/tests/ui/issues/issue-65634-raw-ident-suggestion.rs b/tests/ui/issues/issue-65634-raw-ident-suggestion.rs
index b928510258b..03dd0340c9d 100644
--- a/tests/ui/issues/issue-65634-raw-ident-suggestion.rs
+++ b/tests/ui/issues/issue-65634-raw-ident-suggestion.rs
@@ -1,3 +1,6 @@
+// revisions: edition2015 edition2018
+//[edition2018]edition:2018
+
 #![allow(non_camel_case_types)]
 
 trait r#async {
diff --git a/tests/ui/lifetimes/issue-105507.fixed b/tests/ui/lifetimes/issue-105507.fixed
new file mode 100644
index 00000000000..277ce8a77e9
--- /dev/null
+++ b/tests/ui/lifetimes/issue-105507.fixed
@@ -0,0 +1,43 @@
+// run-rustfix
+//
+#![allow(warnings)]
+struct Wrapper<'a, T: ?Sized>(&'a T);
+
+trait Project {
+    type Projected<'a> where Self: 'a;
+    fn project(this: Wrapper<'_, Self>) -> Self::Projected<'_>;
+}
+trait MyTrait {}
+trait ProjectedMyTrait {}
+
+impl<T> Project for Option<T> {
+    type Projected<'a> = Option<Wrapper<'a, T>> where T: 'a;
+    fn project(this: Wrapper<'_, Self>) -> Self::Projected<'_> {
+        this.0.as_ref().map(Wrapper)
+    }
+}
+
+impl<T: MyTrait> MyTrait for Option<Wrapper<'_, T>> {}
+
+impl<T: ProjectedMyTrait> MyTrait for Wrapper<'_, T> {}
+
+impl<T> ProjectedMyTrait for T
+    where
+        T: Project,
+        for<'a> T::Projected<'a>: MyTrait,
+        //~^ NOTE due to current limitations in the borrow checker, this implies a `'static` lifetime
+        //~| NOTE due to current limitations in the borrow checker, this implies a `'static` lifetime
+{}
+
+fn require_trait<T: MyTrait>(_: T) {}
+
+fn foo<T : MyTrait + 'static + 'static, U : MyTrait + 'static + 'static>(wrap: Wrapper<'_, Option<T>>, wrap1: Wrapper<'_, Option<U>>) {
+    //~^ HELP consider restricting the type parameter to the `'static` lifetime
+    //~| HELP consider restricting the type parameter to the `'static` lifetime
+    require_trait(wrap);
+    //~^ ERROR `T` does not live long enough
+    require_trait(wrap1);
+    //~^ ERROR `U` does not live long enough
+}
+
+fn main() {}
diff --git a/tests/ui/lifetimes/issue-105507.rs b/tests/ui/lifetimes/issue-105507.rs
new file mode 100644
index 00000000000..f46c6b6f21e
--- /dev/null
+++ b/tests/ui/lifetimes/issue-105507.rs
@@ -0,0 +1,43 @@
+// run-rustfix
+//
+#![allow(warnings)]
+struct Wrapper<'a, T: ?Sized>(&'a T);
+
+trait Project {
+    type Projected<'a> where Self: 'a;
+    fn project(this: Wrapper<'_, Self>) -> Self::Projected<'_>;
+}
+trait MyTrait {}
+trait ProjectedMyTrait {}
+
+impl<T> Project for Option<T> {
+    type Projected<'a> = Option<Wrapper<'a, T>> where T: 'a;
+    fn project(this: Wrapper<'_, Self>) -> Self::Projected<'_> {
+        this.0.as_ref().map(Wrapper)
+    }
+}
+
+impl<T: MyTrait> MyTrait for Option<Wrapper<'_, T>> {}
+
+impl<T: ProjectedMyTrait> MyTrait for Wrapper<'_, T> {}
+
+impl<T> ProjectedMyTrait for T
+    where
+        T: Project,
+        for<'a> T::Projected<'a>: MyTrait,
+        //~^ NOTE due to current limitations in the borrow checker, this implies a `'static` lifetime
+        //~| NOTE due to current limitations in the borrow checker, this implies a `'static` lifetime
+{}
+
+fn require_trait<T: MyTrait>(_: T) {}
+
+fn foo<T : MyTrait, U : MyTrait>(wrap: Wrapper<'_, Option<T>>, wrap1: Wrapper<'_, Option<U>>) {
+    //~^ HELP consider restricting the type parameter to the `'static` lifetime
+    //~| HELP consider restricting the type parameter to the `'static` lifetime
+    require_trait(wrap);
+    //~^ ERROR `T` does not live long enough
+    require_trait(wrap1);
+    //~^ ERROR `U` does not live long enough
+}
+
+fn main() {}
diff --git a/tests/ui/lifetimes/issue-105507.stderr b/tests/ui/lifetimes/issue-105507.stderr
new file mode 100644
index 00000000000..44d3a7eb9a4
--- /dev/null
+++ b/tests/ui/lifetimes/issue-105507.stderr
@@ -0,0 +1,34 @@
+error: `T` does not live long enough
+  --> $DIR/issue-105507.rs:37:5
+   |
+LL |     require_trait(wrap);
+   |     ^^^^^^^^^^^^^^^^^^^
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/issue-105507.rs:27:35
+   |
+LL |         for<'a> T::Projected<'a>: MyTrait,
+   |                                   ^^^^^^^
+help: consider restricting the type parameter to the `'static` lifetime
+   |
+LL | fn foo<T : MyTrait + 'static, U : MyTrait + 'static>(wrap: Wrapper<'_, Option<T>>, wrap1: Wrapper<'_, Option<U>>) {
+   |                    +++++++++              +++++++++
+
+error: `U` does not live long enough
+  --> $DIR/issue-105507.rs:39:5
+   |
+LL |     require_trait(wrap1);
+   |     ^^^^^^^^^^^^^^^^^^^^
+   |
+note: due to current limitations in the borrow checker, this implies a `'static` lifetime
+  --> $DIR/issue-105507.rs:27:35
+   |
+LL |         for<'a> T::Projected<'a>: MyTrait,
+   |                                   ^^^^^^^
+help: consider restricting the type parameter to the `'static` lifetime
+   |
+LL | fn foo<T : MyTrait + 'static, U : MyTrait + 'static>(wrap: Wrapper<'_, Option<T>>, wrap1: Wrapper<'_, Option<U>>) {
+   |                    +++++++++              +++++++++
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/limits/issue-15919-32.stderr b/tests/ui/limits/issue-15919-32.stderr
index 133637f9a05..0d79fc0c770 100644
--- a/tests/ui/limits/issue-15919-32.stderr
+++ b/tests/ui/limits/issue-15919-32.stderr
@@ -1,4 +1,4 @@
-error: values of the type `[usize; 4294967295]` are too big for the current architecture
+error: values of the type `[usize; usize::MAX]` are too big for the current architecture
   --> $DIR/issue-15919-32.rs:9:9
    |
 LL |     let x = [0usize; 0xffff_ffff];
diff --git a/tests/ui/limits/issue-15919-64.stderr b/tests/ui/limits/issue-15919-64.stderr
index 193b823035c..3399d644ede 100644
--- a/tests/ui/limits/issue-15919-64.stderr
+++ b/tests/ui/limits/issue-15919-64.stderr
@@ -1,4 +1,4 @@
-error: values of the type `[usize; 18446744073709551615]` are too big for the current architecture
+error: values of the type `[usize; usize::MAX]` are too big for the current architecture
   --> $DIR/issue-15919-64.rs:9:9
    |
 LL |     let x = [0usize; 0xffff_ffff_ffff_ffff];
diff --git a/tests/ui/limits/issue-17913.rs b/tests/ui/limits/issue-17913.rs
index 8d4cbe20184..56cf5d831bd 100644
--- a/tests/ui/limits/issue-17913.rs
+++ b/tests/ui/limits/issue-17913.rs
@@ -1,5 +1,5 @@
 // build-fail
-// normalize-stderr-test "\[&usize; \d+\]" -> "[&usize; N]"
+// normalize-stderr-test "\[&usize; \d+\]" -> "[&usize; usize::MAX]"
 // error-pattern: too big for the current architecture
 
 // FIXME https://github.com/rust-lang/rust/issues/59774
diff --git a/tests/ui/limits/issue-17913.stderr b/tests/ui/limits/issue-17913.stderr
index 9a6431d4470..684db53a919 100644
--- a/tests/ui/limits/issue-17913.stderr
+++ b/tests/ui/limits/issue-17913.stderr
@@ -1,4 +1,4 @@
-error: values of the type `[&usize; N]` are too big for the current architecture
+error: values of the type `[&usize; usize::MAX]` are too big for the current architecture
 
 error: aborting due to previous error
 
diff --git a/tests/ui/limits/issue-55878.stderr b/tests/ui/limits/issue-55878.stderr
index f455dcb06f7..99f1fdf755a 100644
--- a/tests/ui/limits/issue-55878.stderr
+++ b/tests/ui/limits/issue-55878.stderr
@@ -1,7 +1,7 @@
-error[E0080]: values of the type `[u8; SIZE]` are too big for the current architecture
+error[E0080]: values of the type `[u8; usize::MAX]` are too big for the current architecture
   --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
    |
-note: inside `std::mem::size_of::<[u8; SIZE]>`
+note: inside `std::mem::size_of::<[u8; usize::MAX]>`
   --> $SRC_DIR/core/src/mem/mod.rs:LL:COL
 note: inside `main`
   --> $DIR/issue-55878.rs:7:26
diff --git a/tests/ui/limits/issue-69485-var-size-diffs-too-large.stderr b/tests/ui/limits/issue-69485-var-size-diffs-too-large.stderr
index f7923bd4743..44b2be26949 100644
--- a/tests/ui/limits/issue-69485-var-size-diffs-too-large.stderr
+++ b/tests/ui/limits/issue-69485-var-size-diffs-too-large.stderr
@@ -1,4 +1,4 @@
-error: values of the type `[u8; 18446744073709551615]` are too big for the current architecture
+error: values of the type `[u8; usize::MAX]` are too big for the current architecture
   --> $DIR/issue-69485-var-size-diffs-too-large.rs:6:5
    |
 LL |     Bug::V([0; !0]);
diff --git a/tests/ui/limits/issue-75158-64.stderr b/tests/ui/limits/issue-75158-64.stderr
index dc11d056154..d5991bcf569 100644
--- a/tests/ui/limits/issue-75158-64.stderr
+++ b/tests/ui/limits/issue-75158-64.stderr
@@ -1,4 +1,4 @@
-error: values of the type `[u8; 18446744073709551615]` are too big for the current architecture
+error: values of the type `[u8; usize::MAX]` are too big for the current architecture
 
 error: aborting due to previous error
 
diff --git a/tests/ui/lint/issue-30302.rs b/tests/ui/lint/issue-30302.rs
index c37d4f29d10..5eccb8cd5d8 100644
--- a/tests/ui/lint/issue-30302.rs
+++ b/tests/ui/lint/issue-30302.rs
@@ -11,7 +11,7 @@ enum Stack<T> {
 fn is_empty<T>(s: Stack<T>) -> bool {
     match s {
         Nil => true,
-//~^ WARN pattern binding `Nil` is named the same as one of the variants of the type `Stack`
+//~^ ERROR pattern binding `Nil` is named the same as one of the variants of the type `Stack`
         _ => false
 //~^ ERROR unreachable pattern
     }
diff --git a/tests/ui/lint/issue-30302.stderr b/tests/ui/lint/issue-30302.stderr
index 849ff1ebd92..baf6c0d7a59 100644
--- a/tests/ui/lint/issue-30302.stderr
+++ b/tests/ui/lint/issue-30302.stderr
@@ -1,10 +1,10 @@
-warning[E0170]: pattern binding `Nil` is named the same as one of the variants of the type `Stack`
+error[E0170]: pattern binding `Nil` is named the same as one of the variants of the type `Stack`
   --> $DIR/issue-30302.rs:13:9
    |
 LL |         Nil => true,
    |         ^^^ help: to match on the variant, qualify the path: `Stack::Nil`
    |
-   = note: `#[warn(bindings_with_variant_name)]` on by default
+   = note: `#[deny(bindings_with_variant_name)]` on by default
 
 error: unreachable pattern
   --> $DIR/issue-30302.rs:15:9
@@ -21,6 +21,6 @@ note: the lint level is defined here
 LL | #![deny(unreachable_patterns)]
    |         ^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error; 1 warning emitted
+error: aborting due to 2 previous errors
 
 For more information about this error, try `rustc --explain E0170`.
diff --git a/tests/ui/lint/lint-uppercase-variables.rs b/tests/ui/lint/lint-uppercase-variables.rs
index d4e88aa2643..59dba536f24 100644
--- a/tests/ui/lint/lint-uppercase-variables.rs
+++ b/tests/ui/lint/lint-uppercase-variables.rs
@@ -21,18 +21,18 @@ fn main() {
     match foo::Foo::Foo {
         Foo => {}
     //~^ ERROR variable `Foo` should have a snake case name
-    //~^^ WARN `Foo` is named the same as one of the variants of the type `foo::Foo`
+    //~^^ ERROR `Foo` is named the same as one of the variants of the type `foo::Foo`
     //~^^^ WARN unused variable: `Foo`
     }
 
     let Foo = foo::Foo::Foo;
     //~^ ERROR variable `Foo` should have a snake case name
-    //~^^ WARN `Foo` is named the same as one of the variants of the type `foo::Foo`
+    //~^^ ERROR `Foo` is named the same as one of the variants of the type `foo::Foo`
     //~^^^ WARN unused variable: `Foo`
 
     fn in_param(Foo: foo::Foo) {}
     //~^ ERROR variable `Foo` should have a snake case name
-    //~^^ WARN `Foo` is named the same as one of the variants of the type `foo::Foo`
+    //~^^ ERROR `Foo` is named the same as one of the variants of the type `foo::Foo`
     //~^^^ WARN unused variable: `Foo`
 
     test(1);
diff --git a/tests/ui/lint/lint-uppercase-variables.stderr b/tests/ui/lint/lint-uppercase-variables.stderr
index d476d856e24..42ec9364bc6 100644
--- a/tests/ui/lint/lint-uppercase-variables.stderr
+++ b/tests/ui/lint/lint-uppercase-variables.stderr
@@ -1,18 +1,18 @@
-warning[E0170]: pattern binding `Foo` is named the same as one of the variants of the type `foo::Foo`
+error[E0170]: pattern binding `Foo` is named the same as one of the variants of the type `foo::Foo`
   --> $DIR/lint-uppercase-variables.rs:22:9
    |
 LL |         Foo => {}
    |         ^^^ help: to match on the variant, qualify the path: `foo::Foo::Foo`
    |
-   = note: `#[warn(bindings_with_variant_name)]` on by default
+   = note: `#[deny(bindings_with_variant_name)]` on by default
 
-warning[E0170]: pattern binding `Foo` is named the same as one of the variants of the type `foo::Foo`
+error[E0170]: pattern binding `Foo` is named the same as one of the variants of the type `foo::Foo`
   --> $DIR/lint-uppercase-variables.rs:28:9
    |
 LL |     let Foo = foo::Foo::Foo;
    |         ^^^ help: to match on the variant, qualify the path: `foo::Foo::Foo`
 
-warning[E0170]: pattern binding `Foo` is named the same as one of the variants of the type `foo::Foo`
+error[E0170]: pattern binding `Foo` is named the same as one of the variants of the type `foo::Foo`
   --> $DIR/lint-uppercase-variables.rs:33:17
    |
 LL |     fn in_param(Foo: foo::Foo) {}
@@ -85,6 +85,6 @@ error: variable `Foo` should have a snake case name
 LL |     fn in_param(Foo: foo::Foo) {}
    |                 ^^^ help: convert the identifier to snake case (notice the capitalization): `foo`
 
-error: aborting due to 6 previous errors; 6 warnings emitted
+error: aborting due to 9 previous errors; 3 warnings emitted
 
 For more information about this error, try `rustc --explain E0170`.
diff --git a/tests/ui/lint/semicolon-in-expressions-from-macros/semicolon-in-expressions-from-macros.stderr b/tests/ui/lint/semicolon-in-expressions-from-macros/semicolon-in-expressions-from-macros.stderr
index 49608c20524..c6012006164 100644
--- a/tests/ui/lint/semicolon-in-expressions-from-macros/semicolon-in-expressions-from-macros.stderr
+++ b/tests/ui/lint/semicolon-in-expressions-from-macros/semicolon-in-expressions-from-macros.stderr
@@ -46,3 +46,140 @@ LL |     let _ = #[allow(semicolon_in_expressions_from_macros)] foo!(allow_does_
 
 warning: 3 warnings emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/semicolon-in-expressions-from-macros.rs:9:13
+   |
+LL |         true;
+   |             ^
+...
+LL |         foo!(first)
+   |         ----------- in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+   = note: macro invocations at the end of a block are treated as expressions
+   = note: to ignore the value produced by the macro, add a semicolon after the invocation of `foo`
+note: the lint level is defined here
+  --> $DIR/semicolon-in-expressions-from-macros.rs:24:13
+   |
+LL |     #[allow(semicolon_in_expressions_from_macros)]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/semicolon-in-expressions-from-macros.rs:9:13
+   |
+LL |         true;
+   |             ^
+...
+LL |     let _ = foo!(second);
+   |             ------------ in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+note: the lint level is defined here
+  --> $DIR/semicolon-in-expressions-from-macros.rs:29:13
+   |
+LL |     #[allow(semicolon_in_expressions_from_macros)]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/semicolon-in-expressions-from-macros.rs:9:13
+   |
+LL |         true;
+   |             ^
+...
+LL |         let _ = foo!(third);
+   |                 ----------- in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+note: the lint level is defined here
+  --> $DIR/semicolon-in-expressions-from-macros.rs:32:13
+   |
+LL |     #[allow(semicolon_in_expressions_from_macros)]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/semicolon-in-expressions-from-macros.rs:9:13
+   |
+LL |         true;
+   |             ^
+...
+LL |         let _ = foo!(fourth);
+   |                 ------------ in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+note: the lint level is defined here
+  --> $DIR/semicolon-in-expressions-from-macros.rs:37:13
+   |
+LL |     #[allow(semicolon_in_expressions_from_macros)]
+   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/semicolon-in-expressions-from-macros.rs:9:13
+   |
+LL |         true;
+   |             ^
+...
+LL |         foo!(warn_in_block)
+   |         ------------------- in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+   = note: macro invocations at the end of a block are treated as expressions
+   = note: to ignore the value produced by the macro, add a semicolon after the invocation of `foo`
+note: the lint level is defined here
+  --> $DIR/semicolon-in-expressions-from-macros.rs:4:9
+   |
+LL | #![warn(semicolon_in_expressions_from_macros)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/semicolon-in-expressions-from-macros.rs:9:13
+   |
+LL |         true;
+   |             ^
+...
+LL |     let _ = foo!(warn_in_expr);
+   |             ------------------ in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+note: the lint level is defined here
+  --> $DIR/semicolon-in-expressions-from-macros.rs:4:9
+   |
+LL | #![warn(semicolon_in_expressions_from_macros)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/semicolon-in-expressions-from-macros.rs:9:13
+   |
+LL |         true;
+   |             ^
+...
+LL |     let _ = #[allow(semicolon_in_expressions_from_macros)] foo!(allow_does_not_work);
+   |                                                            ------------------------- in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+note: the lint level is defined here
+  --> $DIR/semicolon-in-expressions-from-macros.rs:4:9
+   |
+LL | #![warn(semicolon_in_expressions_from_macros)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
diff --git a/tests/ui/lint/semicolon-in-expressions-from-macros/warn-semicolon-in-expressions-from-macros.stderr b/tests/ui/lint/semicolon-in-expressions-from-macros/warn-semicolon-in-expressions-from-macros.stderr
index 16c152eb23c..0fec4996f1a 100644
--- a/tests/ui/lint/semicolon-in-expressions-from-macros/warn-semicolon-in-expressions-from-macros.stderr
+++ b/tests/ui/lint/semicolon-in-expressions-from-macros/warn-semicolon-in-expressions-from-macros.stderr
@@ -14,3 +14,18 @@ LL |         _ => foo!()
 
 warning: 1 warning emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/warn-semicolon-in-expressions-from-macros.rs:6:13
+   |
+LL |         true;
+   |             ^
+...
+LL |         _ => foo!()
+   |              ------ in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+   = note: `#[warn(semicolon_in_expressions_from_macros)]` on by default
+   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
diff --git a/tests/ui/lint/unused/issue-105061-array-lint.rs b/tests/ui/lint/unused/issue-105061-array-lint.rs
new file mode 100644
index 00000000000..9b06a4fde04
--- /dev/null
+++ b/tests/ui/lint/unused/issue-105061-array-lint.rs
@@ -0,0 +1,11 @@
+#![warn(unused)]
+#![deny(warnings)]
+
+fn main() {
+    let _x: ([u32; 3]); //~ ERROR unnecessary parentheses around type
+    let _y: [u8; (3)]; //~ ERROR unnecessary parentheses around const expression
+    let _z: ([u8; (3)]);
+    //~^ ERROR unnecessary parentheses around const expression
+    //~| ERROR unnecessary parentheses around type
+
+}
diff --git a/tests/ui/lint/unused/issue-105061-array-lint.stderr b/tests/ui/lint/unused/issue-105061-array-lint.stderr
new file mode 100644
index 00000000000..7eb761aee43
--- /dev/null
+++ b/tests/ui/lint/unused/issue-105061-array-lint.stderr
@@ -0,0 +1,56 @@
+error: unnecessary parentheses around type
+  --> $DIR/issue-105061-array-lint.rs:5:13
+   |
+LL |     let _x: ([u32; 3]);
+   |             ^        ^
+   |
+note: the lint level is defined here
+  --> $DIR/issue-105061-array-lint.rs:2:9
+   |
+LL | #![deny(warnings)]
+   |         ^^^^^^^^
+   = note: `#[deny(unused_parens)]` implied by `#[deny(warnings)]`
+help: remove these parentheses
+   |
+LL -     let _x: ([u32; 3]);
+LL +     let _x: [u32; 3];
+   |
+
+error: unnecessary parentheses around const expression
+  --> $DIR/issue-105061-array-lint.rs:6:18
+   |
+LL |     let _y: [u8; (3)];
+   |                  ^ ^
+   |
+help: remove these parentheses
+   |
+LL -     let _y: [u8; (3)];
+LL +     let _y: [u8; 3];
+   |
+
+error: unnecessary parentheses around type
+  --> $DIR/issue-105061-array-lint.rs:7:13
+   |
+LL |     let _z: ([u8; (3)]);
+   |             ^         ^
+   |
+help: remove these parentheses
+   |
+LL -     let _z: ([u8; (3)]);
+LL +     let _z: [u8; (3)];
+   |
+
+error: unnecessary parentheses around const expression
+  --> $DIR/issue-105061-array-lint.rs:7:19
+   |
+LL |     let _z: ([u8; (3)]);
+   |                   ^ ^
+   |
+help: remove these parentheses
+   |
+LL -     let _z: ([u8; (3)]);
+LL +     let _z: ([u8; 3]);
+   |
+
+error: aborting due to 4 previous errors
+
diff --git a/tests/ui/lint/unused/issue-105061-should-lint.rs b/tests/ui/lint/unused/issue-105061-should-lint.rs
new file mode 100644
index 00000000000..7e4e0947349
--- /dev/null
+++ b/tests/ui/lint/unused/issue-105061-should-lint.rs
@@ -0,0 +1,23 @@
+#![warn(unused)]
+#![deny(warnings)]
+
+struct Inv<'a>(&'a mut &'a ());
+
+trait Trait<'a> {}
+impl<'b> Trait<'b> for for<'a> fn(Inv<'a>) {}
+
+fn with_bound()
+where
+    for<'b> (for<'a> fn(Inv<'a>)): Trait<'b>, //~ ERROR unnecessary parentheses around type
+{}
+
+trait Hello<T> {}
+fn with_dyn_bound<T>()
+where
+    (dyn Hello<(for<'b> fn(&'b ()))>): Hello<T> //~ ERROR unnecessary parentheses around type
+{}
+
+fn main() {
+    with_bound();
+    with_dyn_bound();
+}
diff --git a/tests/ui/lint/unused/issue-105061-should-lint.stderr b/tests/ui/lint/unused/issue-105061-should-lint.stderr
new file mode 100644
index 00000000000..e591f1ffb6b
--- /dev/null
+++ b/tests/ui/lint/unused/issue-105061-should-lint.stderr
@@ -0,0 +1,32 @@
+error: unnecessary parentheses around type
+  --> $DIR/issue-105061-should-lint.rs:11:13
+   |
+LL |     for<'b> (for<'a> fn(Inv<'a>)): Trait<'b>,
+   |             ^                   ^
+   |
+note: the lint level is defined here
+  --> $DIR/issue-105061-should-lint.rs:2:9
+   |
+LL | #![deny(warnings)]
+   |         ^^^^^^^^
+   = note: `#[deny(unused_parens)]` implied by `#[deny(warnings)]`
+help: remove these parentheses
+   |
+LL -     for<'b> (for<'a> fn(Inv<'a>)): Trait<'b>,
+LL +     for<'b> for<'a> fn(Inv<'a>): Trait<'b>,
+   |
+
+error: unnecessary parentheses around type
+  --> $DIR/issue-105061-should-lint.rs:17:16
+   |
+LL |     (dyn Hello<(for<'b> fn(&'b ()))>): Hello<T>
+   |                ^                  ^
+   |
+help: remove these parentheses
+   |
+LL -     (dyn Hello<(for<'b> fn(&'b ()))>): Hello<T>
+LL +     (dyn Hello<for<'b> fn(&'b ())>): Hello<T>
+   |
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/lint/unused/issue-105061.rs b/tests/ui/lint/unused/issue-105061.rs
new file mode 100644
index 00000000000..92d636d0ac6
--- /dev/null
+++ b/tests/ui/lint/unused/issue-105061.rs
@@ -0,0 +1,17 @@
+#![warn(unused)]
+#![deny(warnings)]
+
+struct Inv<'a>(&'a mut &'a ());
+
+trait Trait {}
+impl Trait for (for<'a> fn(Inv<'a>),) {}
+
+
+fn with_bound()
+where
+    ((for<'a> fn(Inv<'a>)),): Trait, //~ ERROR unnecessary parentheses around type
+{}
+
+fn main() {
+    with_bound();
+}
diff --git a/tests/ui/lint/unused/issue-105061.stderr b/tests/ui/lint/unused/issue-105061.stderr
new file mode 100644
index 00000000000..f07aa2012df
--- /dev/null
+++ b/tests/ui/lint/unused/issue-105061.stderr
@@ -0,0 +1,20 @@
+error: unnecessary parentheses around type
+  --> $DIR/issue-105061.rs:12:6
+   |
+LL |     ((for<'a> fn(Inv<'a>)),): Trait,
+   |      ^                   ^
+   |
+note: the lint level is defined here
+  --> $DIR/issue-105061.rs:2:9
+   |
+LL | #![deny(warnings)]
+   |         ^^^^^^^^
+   = note: `#[deny(unused_parens)]` implied by `#[deny(warnings)]`
+help: remove these parentheses
+   |
+LL -     ((for<'a> fn(Inv<'a>)),): Trait,
+LL +     (for<'a> fn(Inv<'a>),): Trait,
+   |
+
+error: aborting due to previous error
+
diff --git a/tests/ui/lint/unused_braces.fixed b/tests/ui/lint/unused_braces.fixed
index 1a88d985dd8..e691fb37e6c 100644
--- a/tests/ui/lint/unused_braces.fixed
+++ b/tests/ui/lint/unused_braces.fixed
@@ -50,4 +50,8 @@ fn main() {
     if { return } {
 
     }
+
+    // regression test for https://github.com/rust-lang/rust/issues/106899
+    return println!("!");
+    //~^ WARN unnecessary braces
 }
diff --git a/tests/ui/lint/unused_braces.rs b/tests/ui/lint/unused_braces.rs
index 5ca4811fc32..0d260d2cbc9 100644
--- a/tests/ui/lint/unused_braces.rs
+++ b/tests/ui/lint/unused_braces.rs
@@ -50,4 +50,8 @@ fn main() {
     if { return } {
 
     }
+
+    // regression test for https://github.com/rust-lang/rust/issues/106899
+    return { println!("!") };
+    //~^ WARN unnecessary braces
 }
diff --git a/tests/ui/lint/unused_braces.stderr b/tests/ui/lint/unused_braces.stderr
index 7773f44ea2d..0b4a1c32180 100644
--- a/tests/ui/lint/unused_braces.stderr
+++ b/tests/ui/lint/unused_braces.stderr
@@ -68,5 +68,17 @@ LL -     consume({ 7 });
 LL +     consume(7);
    |
 
-warning: 5 warnings emitted
+warning: unnecessary braces around `return` value
+  --> $DIR/unused_braces.rs:55:12
+   |
+LL |     return { println!("!") };
+   |            ^^             ^^
+   |
+help: remove these braces
+   |
+LL -     return { println!("!") };
+LL +     return println!("!");
+   |
+
+warning: 6 warnings emitted
 
diff --git a/tests/ui/macros/issue-84195-lint-anon-const.stderr b/tests/ui/macros/issue-84195-lint-anon-const.stderr
index 306c08b1357..29ccd17e069 100644
--- a/tests/ui/macros/issue-84195-lint-anon-const.stderr
+++ b/tests/ui/macros/issue-84195-lint-anon-const.stderr
@@ -18,3 +18,22 @@ LL | #![deny(semicolon_in_expressions_from_macros)]
 
 error: aborting due to previous error
 
+Future incompatibility report: Future breakage diagnostic:
+error: trailing semicolon in macro used in expression position
+  --> $DIR/issue-84195-lint-anon-const.rs:8:14
+   |
+LL |     () => { 0; };
+   |              ^
+...
+LL |     let val: [u8; len!()] = [];
+   |                   ------ in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+note: the lint level is defined here
+  --> $DIR/issue-84195-lint-anon-const.rs:5:9
+   |
+LL | #![deny(semicolon_in_expressions_from_macros)]
+   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this error originates in the macro `len` (in Nightly builds, run with -Z macro-backtrace for more info)
+
diff --git a/tests/ui/macros/issue-88228.rs b/tests/ui/macros/issue-88228.rs
index cbdef5f0d40..60ba2eab7a7 100644
--- a/tests/ui/macros/issue-88228.rs
+++ b/tests/ui/macros/issue-88228.rs
@@ -8,7 +8,7 @@ mod hey {
 
 #[derive(Bla)]
 //~^ ERROR cannot find derive macro `Bla`
-//~| NOTE consider importing this derive macro
+//~| HELP consider importing this derive macro
 struct A;
 
 #[derive(println)]
@@ -19,5 +19,5 @@ struct B;
 fn main() {
     bla!();
     //~^ ERROR cannot find macro `bla`
-    //~| NOTE consider importing this macro
+    //~| HELP consider importing this macro
 }
diff --git a/tests/ui/macros/issue-88228.stderr b/tests/ui/macros/issue-88228.stderr
index 62afa67a783..fe8a1deaedd 100644
--- a/tests/ui/macros/issue-88228.stderr
+++ b/tests/ui/macros/issue-88228.stderr
@@ -4,7 +4,7 @@ error: cannot find macro `bla` in this scope
 LL |     bla!();
    |     ^^^
    |
-   = note: consider importing this macro:
+   = help: consider importing this macro:
            crate::hey::bla
 
 error: cannot find derive macro `println` in this scope
@@ -21,7 +21,7 @@ error: cannot find derive macro `Bla` in this scope
 LL | #[derive(Bla)]
    |          ^^^
    |
-   = note: consider importing this derive macro:
+   = help: consider importing this derive macro:
            crate::hey::Bla
 
 error: aborting due to 3 previous errors
diff --git a/tests/ui/macros/lint-trailing-macro-call.stderr b/tests/ui/macros/lint-trailing-macro-call.stderr
index 6ab121f7c06..13cecc3a31d 100644
--- a/tests/ui/macros/lint-trailing-macro-call.stderr
+++ b/tests/ui/macros/lint-trailing-macro-call.stderr
@@ -16,3 +16,20 @@ LL |     expand_it!()
 
 warning: 1 warning emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/lint-trailing-macro-call.rs:9:25
+   |
+LL |         #[cfg(FALSE)] 25;
+   |                         ^
+...
+LL |     expand_it!()
+   |     ------------ in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+   = note: macro invocations at the end of a block are treated as expressions
+   = note: to ignore the value produced by the macro, add a semicolon after the invocation of `expand_it`
+   = note: `#[warn(semicolon_in_expressions_from_macros)]` on by default
+   = note: this warning originates in the macro `expand_it` (in Nightly builds, run with -Z macro-backtrace for more info)
+
diff --git a/tests/ui/macros/macro-context.stderr b/tests/ui/macros/macro-context.stderr
index f597c398b7c..7785f415946 100644
--- a/tests/ui/macros/macro-context.stderr
+++ b/tests/ui/macros/macro-context.stderr
@@ -82,3 +82,18 @@ error: aborting due to 6 previous errors; 1 warning emitted
 
 Some errors have detailed explanations: E0412, E0425.
 For more information about an error, try `rustc --explain E0412`.
+Future incompatibility report: Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/macro-context.rs:3:15
+   |
+LL |     () => ( i ; typeof );
+   |               ^
+...
+LL |     let i = m!();
+   |             ---- in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+   = note: `#[warn(semicolon_in_expressions_from_macros)]` on by default
+   = note: this warning originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+
diff --git a/tests/ui/macros/macro-in-expression-context.stderr b/tests/ui/macros/macro-in-expression-context.stderr
index 36aba8aa08a..3f492b141a5 100644
--- a/tests/ui/macros/macro-in-expression-context.stderr
+++ b/tests/ui/macros/macro-in-expression-context.stderr
@@ -31,3 +31,20 @@ LL |     foo!()
 
 error: aborting due to previous error; 1 warning emitted
 
+Future incompatibility report: Future breakage diagnostic:
+warning: trailing semicolon in macro used in expression position
+  --> $DIR/macro-in-expression-context.rs:5:29
+   |
+LL |         assert_eq!("A", "A");
+   |                             ^
+...
+LL |     foo!()
+   |     ------ in this macro invocation
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #79813 <https://github.com/rust-lang/rust/issues/79813>
+   = note: macro invocations at the end of a block are treated as expressions
+   = note: to ignore the value produced by the macro, add a semicolon after the invocation of `foo`
+   = note: `#[warn(semicolon_in_expressions_from_macros)]` on by default
+   = note: this warning originates in the macro `foo` (in Nightly builds, run with -Z macro-backtrace for more info)
+
diff --git a/tests/ui/macros/macro-use-wrong-name.stderr b/tests/ui/macros/macro-use-wrong-name.stderr
index 326001fc15a..ca5f0f190e8 100644
--- a/tests/ui/macros/macro-use-wrong-name.stderr
+++ b/tests/ui/macros/macro-use-wrong-name.stderr
@@ -9,7 +9,7 @@ LL |     macro_two!();
 LL | macro_rules! macro_one { () => ("one") }
    | ---------------------- similarly named macro `macro_one` defined here
    |
-   = note: consider importing this macro:
+   = help: consider importing this macro:
            two_macros::macro_two
 
 error: aborting due to previous error
diff --git a/tests/ui/mismatched_types/cast-rfc0401.stderr b/tests/ui/mismatched_types/cast-rfc0401.stderr
index eab8e8e80c4..2a36a352c73 100644
--- a/tests/ui/mismatched_types/cast-rfc0401.stderr
+++ b/tests/ui/mismatched_types/cast-rfc0401.stderr
@@ -243,10 +243,12 @@ error[E0606]: casting `&{float}` as `f32` is invalid
   --> $DIR/cast-rfc0401.rs:71:30
    |
 LL |     vec![0.0].iter().map(|s| s as f32).collect::<Vec<f32>>();
-   |                              -^^^^^^^
-   |                              |
-   |                              cannot cast `&{float}` as `f32`
-   |                              help: dereference the expression: `*s`
+   |                              ^^^^^^^^
+   |
+help: dereference the expression
+   |
+LL |     vec![0.0].iter().map(|s| *s as f32).collect::<Vec<f32>>();
+   |                              +
 
 error: aborting due to 34 previous errors
 
diff --git a/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.fixed b/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.fixed
new file mode 100644
index 00000000000..6315fcca2b8
--- /dev/null
+++ b/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.fixed
@@ -0,0 +1,5 @@
+// run-rustfix
+fn main() {
+    let _ = (-10..=10).find(|x: &i32| x.signum() == 0); //~ ERROR type mismatch in closure arguments
+    let _ = (-10..=10).find(|x: &i32| x.signum() == 0); //~ ERROR type mismatch in closure arguments
+}
diff --git a/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.rs b/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.rs
new file mode 100644
index 00000000000..c12c5362efc
--- /dev/null
+++ b/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.rs
@@ -0,0 +1,5 @@
+// run-rustfix
+fn main() {
+    let _ = (-10..=10).find(|x: i32| x.signum() == 0); //~ ERROR type mismatch in closure arguments
+    let _ = (-10..=10).find(|x: &&&i32| x.signum() == 0); //~ ERROR type mismatch in closure arguments
+}
diff --git a/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.stderr b/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.stderr
new file mode 100644
index 00000000000..fb8af4bb7dd
--- /dev/null
+++ b/tests/ui/mismatched_types/closure-arg-type-mismatch-issue-45727.stderr
@@ -0,0 +1,38 @@
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/closure-arg-type-mismatch-issue-45727.rs:3:24
+   |
+LL |     let _ = (-10..=10).find(|x: i32| x.signum() == 0);
+   |                        ^^^^ -------- found signature defined here
+   |                        |
+   |                        expected due to this
+   |
+   = note: expected closure signature `for<'a> fn(&'a {integer}) -> _`
+              found closure signature `fn(i32) -> _`
+note: required by a bound in `find`
+  --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
+help: consider borrowing the argument
+   |
+LL |     let _ = (-10..=10).find(|x: &i32| x.signum() == 0);
+   |                                 +
+
+error[E0631]: type mismatch in closure arguments
+  --> $DIR/closure-arg-type-mismatch-issue-45727.rs:4:24
+   |
+LL |     let _ = (-10..=10).find(|x: &&&i32| x.signum() == 0);
+   |                        ^^^^ ----------- found signature defined here
+   |                        |
+   |                        expected due to this
+   |
+   = note: expected closure signature `for<'a> fn(&'a {integer}) -> _`
+              found closure signature `for<'a, 'b, 'c> fn(&'a &'b &'c i32) -> _`
+note: required by a bound in `find`
+  --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
+help: do not borrow the argument
+   |
+LL -     let _ = (-10..=10).find(|x: &&&i32| x.signum() == 0);
+LL +     let _ = (-10..=10).find(|x: &i32| x.signum() == 0);
+   |
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0631`.
diff --git a/tests/ui/mismatched_types/closure-arg-type-mismatch.stderr b/tests/ui/mismatched_types/closure-arg-type-mismatch.stderr
index fab9b7edc0c..811ff0533f0 100644
--- a/tests/ui/mismatched_types/closure-arg-type-mismatch.stderr
+++ b/tests/ui/mismatched_types/closure-arg-type-mismatch.stderr
@@ -2,16 +2,18 @@ error[E0631]: type mismatch in closure arguments
   --> $DIR/closure-arg-type-mismatch.rs:3:14
    |
 LL |     a.iter().map(|_: (u32, u32)| 45);
-   |              ^^^ ---------------
-   |              |   |   |
-   |              |   |   help: consider borrowing the argument: `&(u32, u32)`
-   |              |   found signature defined here
+   |              ^^^ --------------- found signature defined here
+   |              |
    |              expected due to this
    |
    = note: expected closure signature `fn(&(u32, u32)) -> _`
               found closure signature `fn((u32, u32)) -> _`
 note: required by a bound in `map`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
+help: consider borrowing the argument
+   |
+LL |     a.iter().map(|_: &(u32, u32)| 45);
+   |                      +
 
 error[E0631]: type mismatch in closure arguments
   --> $DIR/closure-arg-type-mismatch.rs:4:14
diff --git a/tests/ui/mismatched_types/issue-36053-2.stderr b/tests/ui/mismatched_types/issue-36053-2.stderr
index 72fb0e4d774..a6764a1dc6d 100644
--- a/tests/ui/mismatched_types/issue-36053-2.stderr
+++ b/tests/ui/mismatched_types/issue-36053-2.stderr
@@ -2,16 +2,18 @@ error[E0631]: type mismatch in closure arguments
   --> $DIR/issue-36053-2.rs:7:32
    |
 LL |     once::<&str>("str").fuse().filter(|a: &str| true).count();
-   |                                ^^^^^^ ---------
-   |                                |      |   |
-   |                                |      |   help: consider borrowing the argument: `&&str`
-   |                                |      found signature defined here
+   |                                ^^^^^^ --------- found signature defined here
+   |                                |
    |                                expected due to this
    |
    = note: expected closure signature `for<'a> fn(&'a &str) -> _`
               found closure signature `for<'a> fn(&'a str) -> _`
 note: required by a bound in `filter`
   --> $SRC_DIR/core/src/iter/traits/iterator.rs:LL:COL
+help: consider borrowing the argument
+   |
+LL |     once::<&str>("str").fuse().filter(|a: &&str| true).count();
+   |                                           +
 
 error[E0599]: the method `count` exists for struct `Filter<Fuse<Once<&str>>, [closure@issue-36053-2.rs:7:39]>`, but its trait bounds were not satisfied
   --> $DIR/issue-36053-2.rs:7:55
diff --git a/tests/ui/missing/missing-macro-use.stderr b/tests/ui/missing/missing-macro-use.stderr
index ced062269df..99e291cda03 100644
--- a/tests/ui/missing/missing-macro-use.stderr
+++ b/tests/ui/missing/missing-macro-use.stderr
@@ -4,7 +4,7 @@ error: cannot find macro `macro_two` in this scope
 LL |     macro_two!();
    |     ^^^^^^^^^
    |
-   = note: consider importing this macro:
+   = help: consider importing this macro:
            two_macros::macro_two
 
 error: aborting due to previous error
diff --git a/tests/ui/parser/recover-unticked-labels.fixed b/tests/ui/parser/recover-unticked-labels.fixed
new file mode 100644
index 00000000000..159d995b8da
--- /dev/null
+++ b/tests/ui/parser/recover-unticked-labels.fixed
@@ -0,0 +1,7 @@
+// run-rustfix
+
+fn main() {
+    'label: loop { break 'label };    //~ error: cannot find value `label` in this scope
+    'label: loop { break 'label 0 };  //~ error: expected a label, found an identifier
+    'label: loop { continue 'label }; //~ error: expected a label, found an identifier
+}
diff --git a/tests/ui/parser/recover-unticked-labels.rs b/tests/ui/parser/recover-unticked-labels.rs
new file mode 100644
index 00000000000..56034de6844
--- /dev/null
+++ b/tests/ui/parser/recover-unticked-labels.rs
@@ -0,0 +1,7 @@
+// run-rustfix
+
+fn main() {
+    'label: loop { break label };    //~ error: cannot find value `label` in this scope
+    'label: loop { break label 0 };  //~ error: expected a label, found an identifier
+    'label: loop { continue label }; //~ error: expected a label, found an identifier
+}
diff --git a/tests/ui/parser/recover-unticked-labels.stderr b/tests/ui/parser/recover-unticked-labels.stderr
new file mode 100644
index 00000000000..c115dffb10e
--- /dev/null
+++ b/tests/ui/parser/recover-unticked-labels.stderr
@@ -0,0 +1,25 @@
+error: expected a label, found an identifier
+  --> $DIR/recover-unticked-labels.rs:5:26
+   |
+LL |     'label: loop { break label 0 };
+   |                          ^^^^^ help: labels start with a tick: `'label`
+
+error: expected a label, found an identifier
+  --> $DIR/recover-unticked-labels.rs:6:29
+   |
+LL |     'label: loop { continue label };
+   |                             ^^^^^ help: labels start with a tick: `'label`
+
+error[E0425]: cannot find value `label` in this scope
+  --> $DIR/recover-unticked-labels.rs:4:26
+   |
+LL |     'label: loop { break label };
+   |     ------               ^^^^^
+   |     |                    |
+   |     |                    not found in this scope
+   |     |                    help: use the similarly named label: `'label`
+   |     a label with a similar name exists
+
+error: aborting due to 3 previous errors
+
+For more information about this error, try `rustc --explain E0425`.
diff --git a/tests/ui/parser/unicode-chars.rs b/tests/ui/parser/unicode-chars.rs
index ba35e95c82a..cd25c756689 100644
--- a/tests/ui/parser/unicode-chars.rs
+++ b/tests/ui/parser/unicode-chars.rs
@@ -2,8 +2,11 @@ fn main() {
     let y = 0;
     //~^ ERROR unknown start of token: \u{37e}
     //~^^ HELP Unicode character ';' (Greek Question Mark) looks like ';' (Semicolon), but it is not
-        let x = 0;
+        let x = 0;
     //~^ ERROR unknown start of token: \u{a0}
     //~^^ NOTE character appears 3 more times
     //~^^^ HELP Unicode character ' ' (No-Break Space) looks like ' ' (Space), but it is not
+    let _ = 1 ⩵ 2;
+    //~^ ERROR unknown start of token
+    //~^^ HELP Unicode character '⩵' (Two Consecutive Equals Signs) looks like '==' (Double Equals Sign), but it is not
 }
diff --git a/tests/ui/parser/unicode-chars.stderr b/tests/ui/parser/unicode-chars.stderr
index 6a5b27872e7..086de5ec099 100644
--- a/tests/ui/parser/unicode-chars.stderr
+++ b/tests/ui/parser/unicode-chars.stderr
@@ -12,14 +12,25 @@ LL |     let y = 0;
 error: unknown start of token: \u{a0}
   --> $DIR/unicode-chars.rs:5:5
    |
-LL |         let x = 0;
+LL |         let x = 0;
    |     ^^^^
    |
    = note: character appears 3 more times
 help: Unicode character ' ' (No-Break Space) looks like ' ' (Space), but it is not
    |
-LL |         let x = 0;
+LL |         let x = 0;
    |     ++++
 
-error: aborting due to 2 previous errors
+error: unknown start of token: \u{2a75}
+  --> $DIR/unicode-chars.rs:9:15
+   |
+LL |     let _ = 1 ⩵ 2;
+   |               ^
+   |
+help: Unicode character '⩵' (Two Consecutive Equals Signs) looks like '==' (Double Equals Sign), but it is not
+   |
+LL |     let _ = 1 == 2;
+   |               ~~
+
+error: aborting due to 3 previous errors
 
diff --git a/tests/ui/pattern/issue-106552.rs b/tests/ui/pattern/issue-106552.rs
new file mode 100644
index 00000000000..aa2c141e05e
--- /dev/null
+++ b/tests/ui/pattern/issue-106552.rs
@@ -0,0 +1,7 @@
+fn main() {
+    let 5 = 6;
+    //~^ error refutable pattern in local binding [E0005]
+
+    let x @ 5 = 6;
+    //~^ error refutable pattern in local binding [E0005]
+}
diff --git a/tests/ui/pattern/issue-106552.stderr b/tests/ui/pattern/issue-106552.stderr
new file mode 100644
index 00000000000..ed5d40c0968
--- /dev/null
+++ b/tests/ui/pattern/issue-106552.stderr
@@ -0,0 +1,35 @@
+error[E0005]: refutable pattern in local binding
+  --> $DIR/issue-106552.rs:2:9
+   |
+LL |     let 5 = 6;
+   |         ^ patterns `i32::MIN..=4_i32` and `6_i32..=i32::MAX` not covered
+   |
+   = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
+   = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
+   = note: the matched value is of type `i32`
+help: you might want to use `if let` to ignore the variants that aren't matched
+   |
+LL |     if let 5 = 6 { todo!() }
+   |     ++           ~~~~~~~~~~~
+help: alternatively, you could prepend the pattern with an underscore to define a new named variable; identifiers cannot begin with digits
+   |
+LL |     let _5 = 6;
+   |         +
+
+error[E0005]: refutable pattern in local binding
+  --> $DIR/issue-106552.rs:5:9
+   |
+LL |     let x @ 5 = 6;
+   |         ^^^^^ patterns `i32::MIN..=4_i32` and `6_i32..=i32::MAX` not covered
+   |
+   = note: `let` bindings require an "irrefutable pattern", like a `struct` or an `enum` with only one variant
+   = note: for more information, visit https://doc.rust-lang.org/book/ch18-02-refutability.html
+   = note: the matched value is of type `i32`
+help: you might want to use `let else` to handle the variants that aren't matched
+   |
+LL |     let x @ 5 = 6 else { todo!() };
+   |                   ++++++++++++++++
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0005`.
diff --git a/tests/ui/pattern/issue-14221.rs b/tests/ui/pattern/issue-14221.rs
index 282c4111369..13427d2c9b2 100644
--- a/tests/ui/pattern/issue-14221.rs
+++ b/tests/ui/pattern/issue-14221.rs
@@ -11,9 +11,9 @@ pub mod b {
     pub fn key(e: ::E) -> &'static str {
         match e {
             A => "A",
-//~^ WARN pattern binding `A` is named the same as one of the variants of the type `E`
+//~^ ERROR pattern binding `A` is named the same as one of the variants of the type `E`
             B => "B", //~ ERROR: unreachable pattern
-//~^ WARN pattern binding `B` is named the same as one of the variants of the type `E`
+//~^ ERROR pattern binding `B` is named the same as one of the variants of the type `E`
         }
     }
 }
diff --git a/tests/ui/pattern/issue-14221.stderr b/tests/ui/pattern/issue-14221.stderr
index fc8ae1ed7b5..7ea51b5f804 100644
--- a/tests/ui/pattern/issue-14221.stderr
+++ b/tests/ui/pattern/issue-14221.stderr
@@ -1,12 +1,12 @@
-warning[E0170]: pattern binding `A` is named the same as one of the variants of the type `E`
+error[E0170]: pattern binding `A` is named the same as one of the variants of the type `E`
   --> $DIR/issue-14221.rs:13:13
    |
 LL |             A => "A",
    |             ^ help: to match on the variant, qualify the path: `E::A`
    |
-   = note: `#[warn(bindings_with_variant_name)]` on by default
+   = note: `#[deny(bindings_with_variant_name)]` on by default
 
-warning[E0170]: pattern binding `B` is named the same as one of the variants of the type `E`
+error[E0170]: pattern binding `B` is named the same as one of the variants of the type `E`
   --> $DIR/issue-14221.rs:15:13
    |
 LL |             B => "B",
@@ -27,6 +27,6 @@ note: the lint level is defined here
 LL | #![deny(unreachable_patterns)]
    |         ^^^^^^^^^^^^^^^^^^^^
 
-error: aborting due to previous error; 2 warnings emitted
+error: aborting due to 3 previous errors
 
 For more information about this error, try `rustc --explain E0170`.
diff --git a/tests/ui/pattern/issue-67776-match-same-name-enum-variant-refs.rs b/tests/ui/pattern/issue-67776-match-same-name-enum-variant-refs.rs
index 6fd5768a5a2..05d097eaf14 100644
--- a/tests/ui/pattern/issue-67776-match-same-name-enum-variant-refs.rs
+++ b/tests/ui/pattern/issue-67776-match-same-name-enum-variant-refs.rs
@@ -1,7 +1,5 @@
 // Test for issue #67776: binding named the same as enum variant
-// should report a warning even when matching against a reference type
-
-// check-pass
+// should report an error even when matching against a reference type
 
 #![allow(unused_variables)]
 #![allow(non_snake_case)]
@@ -15,27 +13,27 @@ enum Foo {
 fn fn1(e: Foo) {
     match e {
         Bar => {},
-        //~^ WARNING named the same as one of the variants of the type `Foo`
+        //~^ ERROR named the same as one of the variants of the type `Foo`
         Baz => {},
-        //~^ WARNING named the same as one of the variants of the type `Foo`
+        //~^ ERROR named the same as one of the variants of the type `Foo`
     }
 }
 
 fn fn2(e: &Foo) {
     match e {
         Bar => {},
-        //~^ WARNING named the same as one of the variants of the type `Foo`
+        //~^ ERROR named the same as one of the variants of the type `Foo`
         Baz => {},
-        //~^ WARNING named the same as one of the variants of the type `Foo`
+        //~^ ERROR named the same as one of the variants of the type `Foo`
     }
 }
 
 fn fn3(e: &mut &&mut Foo) {
     match e {
         Bar => {},
-        //~^ WARNING named the same as one of the variants of the type `Foo`
+        //~^ ERROR named the same as one of the variants of the type `Foo`
         Baz => {},
-        //~^ WARNING named the same as one of the variants of the type `Foo`
+        //~^ ERROR named the same as one of the variants of the type `Foo`
     }
 }
 
diff --git a/tests/ui/pattern/issue-67776-match-same-name-enum-variant-refs.stderr b/tests/ui/pattern/issue-67776-match-same-name-enum-variant-refs.stderr
index 6f3613b63c9..da580c7accb 100644
--- a/tests/ui/pattern/issue-67776-match-same-name-enum-variant-refs.stderr
+++ b/tests/ui/pattern/issue-67776-match-same-name-enum-variant-refs.stderr
@@ -1,41 +1,41 @@
-warning[E0170]: pattern binding `Bar` is named the same as one of the variants of the type `Foo`
-  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:17:9
+error[E0170]: pattern binding `Bar` is named the same as one of the variants of the type `Foo`
+  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:15:9
    |
 LL |         Bar => {},
    |         ^^^ help: to match on the variant, qualify the path: `Foo::Bar`
    |
-   = note: `#[warn(bindings_with_variant_name)]` on by default
+   = note: `#[deny(bindings_with_variant_name)]` on by default
 
-warning[E0170]: pattern binding `Baz` is named the same as one of the variants of the type `Foo`
-  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:19:9
+error[E0170]: pattern binding `Baz` is named the same as one of the variants of the type `Foo`
+  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:17:9
    |
 LL |         Baz => {},
    |         ^^^ help: to match on the variant, qualify the path: `Foo::Baz`
 
-warning[E0170]: pattern binding `Bar` is named the same as one of the variants of the type `Foo`
-  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:26:9
+error[E0170]: pattern binding `Bar` is named the same as one of the variants of the type `Foo`
+  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:24:9
    |
 LL |         Bar => {},
    |         ^^^ help: to match on the variant, qualify the path: `Foo::Bar`
 
-warning[E0170]: pattern binding `Baz` is named the same as one of the variants of the type `Foo`
-  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:28:9
+error[E0170]: pattern binding `Baz` is named the same as one of the variants of the type `Foo`
+  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:26:9
    |
 LL |         Baz => {},
    |         ^^^ help: to match on the variant, qualify the path: `Foo::Baz`
 
-warning[E0170]: pattern binding `Bar` is named the same as one of the variants of the type `Foo`
-  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:35:9
+error[E0170]: pattern binding `Bar` is named the same as one of the variants of the type `Foo`
+  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:33:9
    |
 LL |         Bar => {},
    |         ^^^ help: to match on the variant, qualify the path: `Foo::Bar`
 
-warning[E0170]: pattern binding `Baz` is named the same as one of the variants of the type `Foo`
-  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:37:9
+error[E0170]: pattern binding `Baz` is named the same as one of the variants of the type `Foo`
+  --> $DIR/issue-67776-match-same-name-enum-variant-refs.rs:35:9
    |
 LL |         Baz => {},
    |         ^^^ help: to match on the variant, qualify the path: `Foo::Baz`
 
-warning: 6 warnings emitted
+error: aborting due to 6 previous errors
 
 For more information about this error, try `rustc --explain E0170`.
diff --git a/tests/ui/proc-macro/derive-helper-shadowing.stderr b/tests/ui/proc-macro/derive-helper-shadowing.stderr
index 9c52ca42241..de2c27a878c 100644
--- a/tests/ui/proc-macro/derive-helper-shadowing.stderr
+++ b/tests/ui/proc-macro/derive-helper-shadowing.stderr
@@ -16,7 +16,7 @@ error: cannot find attribute `empty_helper` in this scope
 LL |             #[derive(GenHelperUse)]
    |                      ^^^^^^^^^^^^
    |
-   = note: consider importing this attribute macro:
+   = help: consider importing this attribute macro:
            empty_helper
    = note: this error originates in the derive macro `GenHelperUse` (in Nightly builds, run with -Z macro-backtrace for more info)
 
@@ -29,7 +29,7 @@ LL |         #[empty_helper]
 LL |             gen_helper_use!();
    |             ----------------- in this macro invocation
    |
-   = note: consider importing this attribute macro:
+   = help: consider importing this attribute macro:
            crate::empty_helper
    = note: this error originates in the macro `gen_helper_use` (in Nightly builds, run with -Z macro-backtrace for more info)
 
diff --git a/tests/ui/proc-macro/expand-expr.rs b/tests/ui/proc-macro/expand-expr.rs
index 901b3a95102..700aac41c44 100644
--- a/tests/ui/proc-macro/expand-expr.rs
+++ b/tests/ui/proc-macro/expand-expr.rs
@@ -1,4 +1,6 @@
 // aux-build:expand-expr.rs
+// no-remap-src-base: check_expand_expr_file!() fails when enabled.
+
 #![feature(concat_bytes)]
 extern crate expand_expr;
 
@@ -8,7 +10,7 @@ use expand_expr::{
 
 // Check builtin macros can be expanded.
 
-expand_expr_is!(11u32, line!());
+expand_expr_is!(13u32, line!());
 expand_expr_is!(24u32, column!());
 
 expand_expr_is!("Hello, World!", concat!("Hello, ", "World", "!"));
diff --git a/tests/ui/proc-macro/expand-expr.stderr b/tests/ui/proc-macro/expand-expr.stderr
index 0004f2fe17f..df61e997289 100644
--- a/tests/ui/proc-macro/expand-expr.stderr
+++ b/tests/ui/proc-macro/expand-expr.stderr
@@ -1,29 +1,29 @@
 error: expected one of `.`, `?`, or an operator, found `;`
-  --> $DIR/expand-expr.rs:106:27
+  --> $DIR/expand-expr.rs:108:27
    |
 LL | expand_expr_fail!("string"; hello);
    |                           ^ expected one of `.`, `?`, or an operator
 
 error: expected expression, found `$`
-  --> $DIR/expand-expr.rs:109:19
+  --> $DIR/expand-expr.rs:111:19
    |
 LL | expand_expr_fail!($);
    |                   ^ expected expression
 
 error: expected expression, found `$`
-  --> $DIR/expand-expr.rs:38:23
+  --> $DIR/expand-expr.rs:40:23
    |
 LL |     ($($t:tt)*) => { $($t)* };
    |                       ^^^^ expected expression
 
 error: expected expression, found `$`
-  --> $DIR/expand-expr.rs:111:28
+  --> $DIR/expand-expr.rs:113:28
    |
 LL | expand_expr_fail!(echo_pm!($));
    |                            ^ expected expression
 
 error: macro expansion ignores token `hello` and any following
-  --> $DIR/expand-expr.rs:115:47
+  --> $DIR/expand-expr.rs:117:47
    |
 LL | expand_expr_is!("string", echo_tts!("string"; hello));
    |                           --------------------^^^^^- caused by the macro expansion here
@@ -35,7 +35,7 @@ LL | expand_expr_is!("string", echo_tts!("string"; hello););
    |                                                     +
 
 error: macro expansion ignores token `;` and any following
-  --> $DIR/expand-expr.rs:116:44
+  --> $DIR/expand-expr.rs:118:44
    |
 LL | expand_expr_is!("string", echo_pm!("string"; hello));
    |                           -----------------^------- caused by the macro expansion here
@@ -47,7 +47,7 @@ LL | expand_expr_is!("string", echo_pm!("string"; hello););
    |                                                    +
 
 error: recursion limit reached while expanding `recursive_expand!`
-  --> $DIR/expand-expr.rs:124:16
+  --> $DIR/expand-expr.rs:126:16
    |
 LL | const _: u32 = recursive_expand!();
    |                ^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/proc-macro/generate-mod.rs b/tests/ui/proc-macro/generate-mod.rs
index 9eea630c310..471f317edf9 100644
--- a/tests/ui/proc-macro/generate-mod.rs
+++ b/tests/ui/proc-macro/generate-mod.rs
@@ -15,16 +15,19 @@ struct S;
 
 #[derive(generate_mod::CheckDerive)] //~ ERROR cannot find type `FromOutside` in this scope
                                      //~| ERROR cannot find type `OuterDerive` in this scope
+                                     //~| WARN this was previously accepted
+                                     //~| WARN this was previously accepted
 struct Z;
 
 fn inner_block() {
     #[derive(generate_mod::CheckDerive)] //~ ERROR cannot find type `FromOutside` in this scope
                                         //~| ERROR cannot find type `OuterDerive` in this scope
+                                        //~| WARN this was previously accepted
+                                        //~| WARN this was previously accepted
     struct InnerZ;
 }
 
-#[derive(generate_mod::CheckDeriveLint)] //~  ERROR cannot find type `OuterDeriveLint` in this scope
-                                         //~| ERROR cannot find type `FromOutside` in this scope
+#[derive(generate_mod::CheckDeriveLint)] // OK, lint is suppressed
 struct W;
 
 fn main() {}
diff --git a/tests/ui/proc-macro/generate-mod.stderr b/tests/ui/proc-macro/generate-mod.stderr
index 64042ca0ecd..db629b5b5e2 100644
--- a/tests/ui/proc-macro/generate-mod.stderr
+++ b/tests/ui/proc-macro/generate-mod.stderr
@@ -4,7 +4,7 @@ error[E0412]: cannot find type `FromOutside` in this scope
 LL | generate_mod::check!();
    | ^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
    |
-   = note: consider importing this struct:
+   = help: consider importing this struct:
            FromOutside
    = note: this error originates in the macro `generate_mod::check` (in Nightly builds, run with -Z macro-backtrace for more info)
 
@@ -14,7 +14,7 @@ error[E0412]: cannot find type `Outer` in this scope
 LL | generate_mod::check!();
    | ^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
    |
-   = note: consider importing this struct:
+   = help: consider importing this struct:
            Outer
    = note: this error originates in the macro `generate_mod::check` (in Nightly builds, run with -Z macro-backtrace for more info)
 
@@ -24,7 +24,7 @@ error[E0412]: cannot find type `FromOutside` in this scope
 LL | #[generate_mod::check_attr]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
    |
-   = note: consider importing this struct:
+   = help: consider importing this struct:
            FromOutside
    = note: this error originates in the attribute macro `generate_mod::check_attr` (in Nightly builds, run with -Z macro-backtrace for more info)
 
@@ -34,70 +34,131 @@ error[E0412]: cannot find type `OuterAttr` in this scope
 LL | #[generate_mod::check_attr]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
    |
-   = note: consider importing this struct:
+   = help: consider importing this struct:
            OuterAttr
    = note: this error originates in the attribute macro `generate_mod::check_attr` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0412]: cannot find type `FromOutside` in this scope
+error: cannot find type `FromOutside` in this scope
   --> $DIR/generate-mod.rs:16:10
    |
 LL | #[derive(generate_mod::CheckDerive)]
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
    |
-   = note: consider importing this struct:
-           FromOutside
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+   = note: `#[deny(proc_macro_derive_resolution_fallback)]` on by default
    = note: this error originates in the derive macro `generate_mod::CheckDerive` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0412]: cannot find type `OuterDerive` in this scope
+error: cannot find type `OuterDerive` in this scope
   --> $DIR/generate-mod.rs:16:10
    |
 LL | #[derive(generate_mod::CheckDerive)]
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
    |
-   = note: consider importing this struct:
-           OuterDerive
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
    = note: this error originates in the derive macro `generate_mod::CheckDerive` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0412]: cannot find type `FromOutside` in this scope
-  --> $DIR/generate-mod.rs:21:14
+error: cannot find type `FromOutside` in this scope
+  --> $DIR/generate-mod.rs:23:14
    |
 LL |     #[derive(generate_mod::CheckDerive)]
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
    |
-   = note: consider importing this struct:
-           FromOutside
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
    = note: this error originates in the derive macro `generate_mod::CheckDerive` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0412]: cannot find type `OuterDerive` in this scope
-  --> $DIR/generate-mod.rs:21:14
+error: cannot find type `OuterDerive` in this scope
+  --> $DIR/generate-mod.rs:23:14
    |
 LL |     #[derive(generate_mod::CheckDerive)]
-   |              ^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
    |
-   = note: consider importing this struct:
-           OuterDerive
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
    = note: this error originates in the derive macro `generate_mod::CheckDerive` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0412]: cannot find type `FromOutside` in this scope
-  --> $DIR/generate-mod.rs:26:10
+error: aborting due to 8 previous errors
+
+For more information about this error, try `rustc --explain E0412`.
+Future incompatibility report: Future breakage diagnostic:
+error: cannot find type `FromOutside` in this scope
+  --> $DIR/generate-mod.rs:16:10
    |
-LL | #[derive(generate_mod::CheckDeriveLint)]
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+LL | #[derive(generate_mod::CheckDerive)]
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
    |
-   = note: consider importing this struct:
-           FromOutside
-   = note: this error originates in the derive macro `generate_mod::CheckDeriveLint` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+   = note: `#[deny(proc_macro_derive_resolution_fallback)]` on by default
+   = note: this error originates in the derive macro `generate_mod::CheckDerive` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+Future breakage diagnostic:
+error: cannot find type `OuterDerive` in this scope
+  --> $DIR/generate-mod.rs:16:10
+   |
+LL | #[derive(generate_mod::CheckDerive)]
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+   = note: `#[deny(proc_macro_derive_resolution_fallback)]` on by default
+   = note: this error originates in the derive macro `generate_mod::CheckDerive` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0412]: cannot find type `OuterDeriveLint` in this scope
-  --> $DIR/generate-mod.rs:26:10
+Future breakage diagnostic:
+error: cannot find type `FromOutside` in this scope
+  --> $DIR/generate-mod.rs:23:14
    |
-LL | #[derive(generate_mod::CheckDeriveLint)]
-   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ not found in this scope
+LL |     #[derive(generate_mod::CheckDerive)]
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
    |
-   = note: consider importing this struct:
-           OuterDeriveLint
-   = note: this error originates in the derive macro `generate_mod::CheckDeriveLint` (in Nightly builds, run with -Z macro-backtrace for more info)
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+   = note: `#[deny(proc_macro_derive_resolution_fallback)]` on by default
+   = note: this error originates in the derive macro `generate_mod::CheckDerive` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 10 previous errors
+Future breakage diagnostic:
+error: cannot find type `OuterDerive` in this scope
+  --> $DIR/generate-mod.rs:23:14
+   |
+LL |     #[derive(generate_mod::CheckDerive)]
+   |              ^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+   = note: `#[deny(proc_macro_derive_resolution_fallback)]` on by default
+   = note: this error originates in the derive macro `generate_mod::CheckDerive` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+Future breakage diagnostic:
+warning: cannot find type `FromOutside` in this scope
+  --> $DIR/generate-mod.rs:30:10
+   |
+LL | #[derive(generate_mod::CheckDeriveLint)] // OK, lint is suppressed
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+note: the lint level is defined here
+  --> $DIR/generate-mod.rs:30:10
+   |
+LL | #[derive(generate_mod::CheckDeriveLint)] // OK, lint is suppressed
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this warning originates in the derive macro `generate_mod::CheckDeriveLint` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+Future breakage diagnostic:
+warning: cannot find type `OuterDeriveLint` in this scope
+  --> $DIR/generate-mod.rs:30:10
+   |
+LL | #[derive(generate_mod::CheckDeriveLint)] // OK, lint is suppressed
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ names from parent modules are not accessible without an explicit import
+   |
+   = warning: this was previously accepted by the compiler but is being phased out; it will become a hard error in a future release!
+   = note: for more information, see issue #83583 <https://github.com/rust-lang/rust/issues/83583>
+note: the lint level is defined here
+  --> $DIR/generate-mod.rs:30:10
+   |
+LL | #[derive(generate_mod::CheckDeriveLint)] // OK, lint is suppressed
+   |          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: this warning originates in the derive macro `generate_mod::CheckDeriveLint` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-For more information about this error, try `rustc --explain E0412`.
diff --git a/tests/ui/proc-macro/pretty-print-hack-show.remapped.stderr b/tests/ui/proc-macro/pretty-print-hack-show.remapped.stderr
index ab501384889..873054927c9 100644
--- a/tests/ui/proc-macro/pretty-print-hack-show.remapped.stderr
+++ b/tests/ui/proc-macro/pretty-print-hack-show.remapped.stderr
@@ -1,5 +1,5 @@
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -10,7 +10,7 @@ LL | enum ProceduralMasqueradeDummyType {
    = note: `#[deny(proc_macro_back_compat)]` on by default
 
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -20,7 +20,7 @@ LL | enum ProceduralMasqueradeDummyType {
    = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
 
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -30,7 +30,7 @@ LL | enum ProceduralMasqueradeDummyType {
    = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
 
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -40,7 +40,7 @@ LL | enum ProceduralMasqueradeDummyType {
    = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
 
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -50,7 +50,7 @@ LL | enum ProceduralMasqueradeDummyType {
    = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
 
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -60,7 +60,7 @@ LL | enum ProceduralMasqueradeDummyType {
    = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
 
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -70,7 +70,7 @@ LL | enum ProceduralMasqueradeDummyType {
    = note: older versions of the `rental` crate will stop compiling in future versions of Rust; please update to `rental` v0.5.6, or switch to one of the `rental` alternatives
 
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -83,7 +83,7 @@ error: aborting due to 8 previous errors
 
 Future incompatibility report: Future breakage diagnostic:
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -95,7 +95,7 @@ LL | enum ProceduralMasqueradeDummyType {
 
 Future breakage diagnostic:
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -107,7 +107,7 @@ LL | enum ProceduralMasqueradeDummyType {
 
 Future breakage diagnostic:
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -119,7 +119,7 @@ LL | enum ProceduralMasqueradeDummyType {
 
 Future breakage diagnostic:
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -131,7 +131,7 @@ LL | enum ProceduralMasqueradeDummyType {
 
 Future breakage diagnostic:
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -143,7 +143,7 @@ LL | enum ProceduralMasqueradeDummyType {
 
 Future breakage diagnostic:
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -155,7 +155,7 @@ LL | enum ProceduralMasqueradeDummyType {
 
 Future breakage diagnostic:
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -167,7 +167,7 @@ LL | enum ProceduralMasqueradeDummyType {
 
 Future breakage diagnostic:
 error: using an old version of `rental`
-  --> remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
+  --> $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6
    |
 LL | enum ProceduralMasqueradeDummyType {
    |      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/tests/ui/proc-macro/pretty-print-hack-show.remapped.stdout b/tests/ui/proc-macro/pretty-print-hack-show.remapped.stdout
index 61ca53b28d4..3d793d2a014 100644
--- a/tests/ui/proc-macro/pretty-print-hack-show.remapped.stdout
+++ b/tests/ui/proc-macro/pretty-print-hack-show.remapped.stdout
@@ -3,21 +3,21 @@ PRINT-DERIVE RE-COLLECTED (DISPLAY): enum ProceduralMasqueradeDummyType { Input
 PRINT-DERIVE INPUT (DEBUG): TokenStream [
     Ident {
         ident: "enum",
-        span: remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:1: 4:5 (#0),
+        span: $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:1: 4:5 (#0),
     },
     Ident {
         ident: "ProceduralMasqueradeDummyType",
-        span: remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6: 4:35 (#0),
+        span: $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:6: 4:35 (#0),
     },
     Group {
         delimiter: Brace,
         stream: TokenStream [
             Ident {
                 ident: "Input",
-                span: remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:13:5: 13:10 (#0),
+                span: $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:13:5: 13:10 (#0),
             },
         ],
-        span: remapped/proc-macro/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:36: 14:2 (#0),
+        span: $DIR/pretty-print-hack/allsorts-rental-0.5.6/src/lib.rs:4:36: 14:2 (#0),
     },
 ]
 PRINT-DERIVE INPUT (DISPLAY): enum ProceduralMasqueradeDummyType { Input, }
@@ -25,20 +25,20 @@ PRINT-DERIVE RE-COLLECTED (DISPLAY): enum ProceduralMasqueradeDummyType { Input
 PRINT-DERIVE INPUT (DEBUG): TokenStream [
     Ident {
         ident: "enum",
-        span: remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:1: 4:5 (#0),
+        span: $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:1: 4:5 (#0),
     },
     Ident {
         ident: "ProceduralMasqueradeDummyType",
-        span: remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6: 4:35 (#0),
+        span: $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:6: 4:35 (#0),
     },
     Group {
         delimiter: Brace,
         stream: TokenStream [
             Ident {
                 ident: "Input",
-                span: remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:13:5: 13:10 (#0),
+                span: $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:13:5: 13:10 (#0),
             },
         ],
-        span: remapped/proc-macro/pretty-print-hack/rental-0.5.5/src/lib.rs:4:36: 14:2 (#0),
+        span: $DIR/pretty-print-hack/rental-0.5.5/src/lib.rs:4:36: 14:2 (#0),
     },
 ]
diff --git a/tests/ui/proc-macro/pretty-print-hack-show.rs b/tests/ui/proc-macro/pretty-print-hack-show.rs
index e9ff66ba45a..24a389c450e 100644
--- a/tests/ui/proc-macro/pretty-print-hack-show.rs
+++ b/tests/ui/proc-macro/pretty-print-hack-show.rs
@@ -1,11 +1,8 @@
 // aux-build:test-macros.rs
 // compile-flags: -Z span-debug
 // revisions: local remapped
-// [remapped]compile-flags: --remap-path-prefix={{src-base}}=remapped
-
-// The remapped paths are not normalized by compiletest.
-// normalize-stdout-test: "\\(proc-macro|pretty-print-hack)" -> "/$1"
-// normalize-stderr-test: "\\(proc-macro|pretty-print-hack)" -> "/$1"
+// [local] no-remap-src-base: The hack should work regardless of remapping.
+// [remapped] remap-src-base
 
 #![no_std] // Don't load unnecessary hygiene information from std
 extern crate std;
diff --git a/tests/ui/rfc-2126-extern-absolute-paths/not-allowed.stderr b/tests/ui/rfc-2126-extern-absolute-paths/not-allowed.stderr
index 761089cd387..122e8fd350c 100644
--- a/tests/ui/rfc-2126-extern-absolute-paths/not-allowed.stderr
+++ b/tests/ui/rfc-2126-extern-absolute-paths/not-allowed.stderr
@@ -7,9 +7,9 @@ LL | use alloc;
 help: consider importing one of these items instead
    |
 LL | use core::alloc;
-   |     ~~~~~~~~~~~~
-LL | use std::alloc;
    |     ~~~~~~~~~~~
+LL | use std::alloc;
+   |     ~~~~~~~~~~
 
 error: aborting due to previous error
 
diff --git a/tests/ui/simd/portable-intrinsics-arent-exposed.stderr b/tests/ui/simd/portable-intrinsics-arent-exposed.stderr
index 8881ede0dbc..f8b3e6d65af 100644
--- a/tests/ui/simd/portable-intrinsics-arent-exposed.stderr
+++ b/tests/ui/simd/portable-intrinsics-arent-exposed.stderr
@@ -15,7 +15,7 @@ LL | use std::simd::intrinsics;
 help: consider importing this module instead
    |
 LL | use std::intrinsics;
-   |     ~~~~~~~~~~~~~~~~
+   |     ~~~~~~~~~~~~~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/single-use-lifetime/issue-104440.rs b/tests/ui/single-use-lifetime/issue-104440.rs
new file mode 100644
index 00000000000..0795e95303a
--- /dev/null
+++ b/tests/ui/single-use-lifetime/issue-104440.rs
@@ -0,0 +1,100 @@
+#![feature(decl_macro, rustc_attrs)]
+#![deny(single_use_lifetimes)]
+
+mod type_params {
+    macro m($T:ident) {
+        fn f<$T: Clone, T: PartialEq>(t1: $T, t2: T) -> ($T, bool) {
+            (t1.clone(), t2 == t2)
+        }
+    }
+
+    #[rustc_macro_transparency = "semitransparent"]
+    macro n($T:ident) {
+        fn g<$T: Clone>(t1: $T, t2: T) -> (T, $T) {
+            (t1.clone(), t2.clone())
+        }
+        fn h<T: Clone>(t1: $T, t2: T) -> (T, $T) {
+            (t1.clone(), t2.clone())
+        }
+    }
+
+    #[rustc_macro_transparency = "transparent"]
+    macro p($T:ident) {
+        fn j<$T: Clone>(t1: $T, t2: T) -> (T, $T) {
+            (t1.clone(), t2.clone())
+        }
+        fn k<T: Clone>(t1: $T, t2: T) -> (T, $T) {
+            (t1.clone(), t2.clone())
+        }
+    }
+
+    m!(T);
+    n!(T);
+    p!(T);
+}
+
+mod lifetime_params {
+    macro m($a:lifetime) {
+        fn f<'b, 'c, $a: 'b, 'a: 'c>(t1: &$a(), t2: &'a ()) -> (&'b (), &'c ()) { //~ ERROR lifetime parameter `'a` only used once
+            (t1, t2)
+        }
+    }
+
+    #[rustc_macro_transparency = "semitransparent"]
+    macro n($a:lifetime) {
+        fn g<$a>(t1: &$a(), t2: &'a ()) -> (&'a (), &$a ()) {
+            (t1, t2)
+        }
+        fn h<'a>(t1: &$a(), t2: &'a ()) -> (&'a (), &$a ()) {
+            (t1, t2)
+        }
+    }
+
+    #[rustc_macro_transparency = "transparent"]
+    macro p($a:lifetime) {
+        fn j<$a>(t1: &$a(), t2: &'a ()) -> (&'a (), &$a ()) {
+            (t1, t2)
+        }
+        fn k<'a>(t1: &$a(), t2: &'a ()) -> (&'a (), &$a ()) {
+            (t1, t2)
+        }
+    }
+
+    m!('a); //~ ERROR lifetime parameter `'a` only used once
+    n!('a);
+    p!('a);
+}
+
+mod const_params {
+    macro m($C:ident) {
+        fn f<const $C: usize, const C: usize>(t1: [(); $C], t2: [(); C]) -> ([(); $C], [(); C]) {
+            (t1, t2)
+        }
+    }
+
+    #[rustc_macro_transparency = "semitransparent"]
+    macro n($C:ident) {
+        fn g<const $C: usize>(t1: [(); $C], t2: [(); C]) -> ([(); C], [(); $C]) {
+            (t1, t2)
+        }
+        fn h<const C: usize>(t1: [(); $C], t2: [(); C]) -> ([(); C], [(); $C]) {
+            (t1, t2)
+        }
+    }
+
+    #[rustc_macro_transparency = "transparent"]
+    macro p($C:ident) {
+        fn j<const $C: usize>(t1: [(); $C], t2: [(); C]) -> ([(); C], [(); $C]) {
+            (t1, t2)
+        }
+        fn k<const C: usize>(t1: [(); $C], t2: [(); C]) -> ([(); C], [(); $C]) {
+            (t1, t2)
+        }
+    }
+
+    m!(C);
+    n!(C);
+    p!(C);
+}
+
+fn main() {}
diff --git a/tests/ui/single-use-lifetime/issue-104440.stderr b/tests/ui/single-use-lifetime/issue-104440.stderr
new file mode 100644
index 00000000000..54ded31dcbe
--- /dev/null
+++ b/tests/ui/single-use-lifetime/issue-104440.stderr
@@ -0,0 +1,28 @@
+error: lifetime parameter `'a` only used once
+  --> $DIR/issue-104440.rs:63:8
+   |
+LL |     m!('a);
+   |        ^^
+   |        |
+   |        this lifetime...
+   |        ...is used only here
+   |
+note: the lint level is defined here
+  --> $DIR/issue-104440.rs:2:9
+   |
+LL | #![deny(single_use_lifetimes)]
+   |         ^^^^^^^^^^^^^^^^^^^^
+
+error: lifetime parameter `'a` only used once
+  --> $DIR/issue-104440.rs:38:30
+   |
+LL |         fn f<'b, 'c, $a: 'b, 'a: 'c>(t1: &$a(), t2: &'a ()) -> (&'b (), &'c ()) {
+   |                              ^^ this lifetime...     -- ...is used only here
+...
+LL |     m!('a);
+   |     ------ in this macro invocation
+   |
+   = note: this error originates in the macro `m` (in Nightly builds, run with -Z macro-backtrace for more info)
+
+error: aborting due to 2 previous errors
+
diff --git a/tests/ui/stability-attribute/issue-106589.rs b/tests/ui/stability-attribute/issue-106589.rs
new file mode 100644
index 00000000000..3cad9a3d283
--- /dev/null
+++ b/tests/ui/stability-attribute/issue-106589.rs
@@ -0,0 +1,10 @@
+// #![feature(staged_api)] // note: `staged_api` not enabled
+
+#![stable(feature = "foo", since = "1.0.0")]
+//~^ ERROR stability attributes may not be used outside of the standard library
+
+#[unstable(feature = "foo", issue = "none")]
+//~^ ERROR stability attributes may not be used outside of the standard library
+fn foo_unstable() {}
+
+fn main() {}
diff --git a/tests/ui/stability-attribute/issue-106589.stderr b/tests/ui/stability-attribute/issue-106589.stderr
new file mode 100644
index 00000000000..ccf3f7164e3
--- /dev/null
+++ b/tests/ui/stability-attribute/issue-106589.stderr
@@ -0,0 +1,15 @@
+error[E0734]: stability attributes may not be used outside of the standard library
+  --> $DIR/issue-106589.rs:6:1
+   |
+LL | #[unstable(feature = "foo", issue = "none")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error[E0734]: stability attributes may not be used outside of the standard library
+  --> $DIR/issue-106589.rs:3:1
+   |
+LL | #![stable(feature = "foo", since = "1.0.0")]
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+error: aborting due to 2 previous errors
+
+For more information about this error, try `rustc --explain E0734`.
diff --git a/tests/ui/suggestions/constrain-suggest-ice.stderr b/tests/ui/suggestions/constrain-suggest-ice.stderr
index 477eb278679..2af7c2f6971 100644
--- a/tests/ui/suggestions/constrain-suggest-ice.stderr
+++ b/tests/ui/suggestions/constrain-suggest-ice.stderr
@@ -24,16 +24,7 @@ error[E0425]: cannot find value `F` in this scope
   --> $DIR/constrain-suggest-ice.rs:6:9
    |
 LL |         F
-   |         ^
-   |
-help: a local variable with a similar name exists
-   |
-LL |         x
-   |         ~
-help: you might be missing a type parameter
-   |
-LL | struct Bug<S, F>{
-   |             +++
+   |         ^ help: a local variable with a similar name exists: `x`
 
 error: generic `Self` types are currently not permitted in anonymous constants
   --> $DIR/constrain-suggest-ice.rs:3:21
diff --git a/tests/ui/suggestions/issue-88730.rs b/tests/ui/suggestions/issue-88730.rs
index e63210a3e98..d161ed284f6 100644
--- a/tests/ui/suggestions/issue-88730.rs
+++ b/tests/ui/suggestions/issue-88730.rs
@@ -1,9 +1,8 @@
 #![allow(unused, nonstandard_style)]
-#![deny(bindings_with_variant_name)]
 
 // If an enum has two different variants,
 // then it cannot be matched upon in a function argument.
-// It still gets a warning, but no suggestions.
+// It still gets an error, but no suggestions.
 enum Foo {
     C,
     D,
diff --git a/tests/ui/suggestions/issue-88730.stderr b/tests/ui/suggestions/issue-88730.stderr
index eb22b0ea5c8..0bd1b7ba4ba 100644
--- a/tests/ui/suggestions/issue-88730.stderr
+++ b/tests/ui/suggestions/issue-88730.stderr
@@ -1,17 +1,13 @@
 error[E0170]: pattern binding `C` is named the same as one of the variants of the type `Foo`
-  --> $DIR/issue-88730.rs:12:8
+  --> $DIR/issue-88730.rs:11:8
    |
 LL | fn foo(C: Foo) {}
    |        ^
    |
-note: the lint level is defined here
-  --> $DIR/issue-88730.rs:2:9
-   |
-LL | #![deny(bindings_with_variant_name)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^
+   = note: `#[deny(bindings_with_variant_name)]` on by default
 
 error[E0170]: pattern binding `C` is named the same as one of the variants of the type `Foo`
-  --> $DIR/issue-88730.rs:15:9
+  --> $DIR/issue-88730.rs:14:9
    |
 LL |     let C = Foo::D;
    |         ^
diff --git a/tests/ui/symbol-names/impl2.rs b/tests/ui/symbol-names/impl2.rs
index 08add29cb9c..81aba403d0b 100644
--- a/tests/ui/symbol-names/impl2.rs
+++ b/tests/ui/symbol-names/impl2.rs
@@ -8,9 +8,8 @@ trait Foo {
 }
 
 impl Foo for [u8; 1 + 2] {
-    #[rustc_def_path] //~ ERROR def-path(<[u8; _] as Foo>::baz)
-    fn baz() { }
+    #[rustc_def_path] //~ ERROR def-path(<[u8; 1 + 2] as Foo>::baz)
+    fn baz() {}
 }
 
-fn main() {
-}
+fn main() {}
diff --git a/tests/ui/symbol-names/impl2.stderr b/tests/ui/symbol-names/impl2.stderr
index 98330031602..0c3205e0108 100644
--- a/tests/ui/symbol-names/impl2.stderr
+++ b/tests/ui/symbol-names/impl2.stderr
@@ -1,4 +1,4 @@
-error: def-path(<[u8; _] as Foo>::baz)
+error: def-path(<[u8; 1 + 2] as Foo>::baz)
   --> $DIR/impl2.rs:11:5
    |
 LL |     #[rustc_def_path]
diff --git a/tests/ui/test-attrs/inaccessible-test-modules.stderr b/tests/ui/test-attrs/inaccessible-test-modules.stderr
index a45c5bd4588..7635f579d66 100644
--- a/tests/ui/test-attrs/inaccessible-test-modules.stderr
+++ b/tests/ui/test-attrs/inaccessible-test-modules.stderr
@@ -13,7 +13,7 @@ LL | use test as y;
 help: consider importing this module instead
    |
 LL | use test::test as y;
-   |     ~~~~~~~~~~~~~~~~
+   |     ~~~~~~~~~~~~~~~
 
 error: aborting due to 2 previous errors
 
diff --git a/tests/ui/traits/copy-impl-cannot-normalize.stderr b/tests/ui/traits/copy-impl-cannot-normalize.stderr
index 68b95b42b34..86c511c0895 100644
--- a/tests/ui/traits/copy-impl-cannot-normalize.stderr
+++ b/tests/ui/traits/copy-impl-cannot-normalize.stderr
@@ -4,6 +4,16 @@ error[E0277]: the trait bound `T: TraitFoo` is not satisfied
 LL | impl<T> Copy for Foo<T> {}
    |                  ^^^^^^ the trait `TraitFoo` is not implemented for `T`
    |
+note: required for `Foo<T>` to implement `Clone`
+  --> $DIR/copy-impl-cannot-normalize.rs:12:9
+   |
+LL | impl<T> Clone for Foo<T>
+   |         ^^^^^     ^^^^^^
+LL | where
+LL |     T: TraitFoo,
+   |        -------- unsatisfied trait bound introduced here
+note: required by a bound in `Copy`
+  --> $SRC_DIR/core/src/marker.rs:LL:COL
 help: consider restricting type parameter `T`
    |
 LL | impl<T: TraitFoo> Copy for Foo<T> {}
diff --git a/tests/ui/traits/copy-is-not-modulo-regions.not_static.stderr b/tests/ui/traits/copy-is-not-modulo-regions.not_static.stderr
new file mode 100644
index 00000000000..edd94d2010b
--- /dev/null
+++ b/tests/ui/traits/copy-is-not-modulo-regions.not_static.stderr
@@ -0,0 +1,22 @@
+error[E0204]: the trait `Copy` may not be implemented for this type
+  --> $DIR/copy-is-not-modulo-regions.rs:13:21
+   |
+LL | struct Bar<'lt>(Foo<'lt>);
+   |                 -------- this field does not implement `Copy`
+...
+LL | impl<'any> Copy for Bar<'any> {}
+   |                     ^^^^^^^^^
+   |
+note: the `Copy` impl for `Foo<'any>` requires that `'any: 'static`
+  --> $DIR/copy-is-not-modulo-regions.rs:10:17
+   |
+LL | struct Bar<'lt>(Foo<'lt>);
+   |                 ^^^^^^^^
+help: consider restricting type parameter `'any`
+   |
+LL | impl<'any: 'static> Copy for Bar<'any> {}
+   |          +++++++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0204`.
diff --git a/tests/ui/traits/copy-is-not-modulo-regions.rs b/tests/ui/traits/copy-is-not-modulo-regions.rs
new file mode 100644
index 00000000000..adb87023769
--- /dev/null
+++ b/tests/ui/traits/copy-is-not-modulo-regions.rs
@@ -0,0 +1,19 @@
+// revisions: not_static yes_static
+//[yes_static] check-pass
+
+#[derive(Clone)]
+struct Foo<'lt>(&'lt ());
+
+impl Copy for Foo<'static> {}
+
+#[derive(Clone)]
+struct Bar<'lt>(Foo<'lt>);
+
+#[cfg(not_static)]
+impl<'any> Copy for Bar<'any> {}
+//[not_static]~^ the trait `Copy` may not be implemented for this type
+
+#[cfg(yes_static)]
+impl<'any> Copy for Bar<'static> {}
+
+fn main() {}
diff --git a/tests/ui/traits/copy-requires-self-wf.rs b/tests/ui/traits/copy-requires-self-wf.rs
new file mode 100644
index 00000000000..9abfdfab9d0
--- /dev/null
+++ b/tests/ui/traits/copy-requires-self-wf.rs
@@ -0,0 +1,14 @@
+// check-pass
+
+#[derive(Clone)]
+struct A<'a, T>(&'a T);
+
+impl<'a, T: Copy + 'a> Copy for A<'a, T> {}
+
+#[derive(Clone)]
+struct B<'a, T>(A<'a, T>);
+
+// `T: '_` should be implied by `WF(B<'_, T>)`.
+impl<T: Copy> Copy for B<'_, T> {}
+
+fn main() {}
diff --git a/tests/ui/traits/issue-50480.rs b/tests/ui/traits/issue-50480.rs
index 10597caf5b2..005939e0c46 100644
--- a/tests/ui/traits/issue-50480.rs
+++ b/tests/ui/traits/issue-50480.rs
@@ -5,13 +5,11 @@ struct Foo(N, NotDefined, <i32 as Iterator>::Item, Vec<i32>, String);
 //~| ERROR cannot find type `NotDefined` in this scope
 //~| ERROR cannot find type `N` in this scope
 //~| ERROR cannot find type `N` in this scope
-//~| ERROR `i32` is not an iterator
 
 #[derive(Clone, Copy)]
 //~^ ERROR the trait `Copy` may not be implemented for this type
 struct Bar<T>(T, N, NotDefined, <i32 as Iterator>::Item, Vec<i32>, String);
 //~^ ERROR cannot find type `NotDefined` in this scope
 //~| ERROR cannot find type `N` in this scope
-//~| ERROR `i32` is not an iterator
 
 fn main() {}
diff --git a/tests/ui/traits/issue-50480.stderr b/tests/ui/traits/issue-50480.stderr
index aa8384e9805..5063fdca092 100644
--- a/tests/ui/traits/issue-50480.stderr
+++ b/tests/ui/traits/issue-50480.stderr
@@ -38,7 +38,7 @@ LL | struct Foo<NotDefined>(N, NotDefined, <i32 as Iterator>::Item, Vec<i32>, St
    |           ++++++++++++
 
 error[E0412]: cannot find type `N` in this scope
-  --> $DIR/issue-50480.rs:12:18
+  --> $DIR/issue-50480.rs:11:18
    |
 LL | struct Bar<T>(T, N, NotDefined, <i32 as Iterator>::Item, Vec<i32>, String);
    |            -     ^
@@ -55,20 +55,11 @@ LL | struct Bar<T, N>(T, N, NotDefined, <i32 as Iterator>::Item, Vec<i32>, Strin
    |             +++
 
 error[E0412]: cannot find type `NotDefined` in this scope
-  --> $DIR/issue-50480.rs:12:21
+  --> $DIR/issue-50480.rs:11:21
    |
 LL | struct Bar<T>(T, N, NotDefined, <i32 as Iterator>::Item, Vec<i32>, String);
    |                     ^^^^^^^^^^ not found in this scope
 
-error[E0277]: `i32` is not an iterator
-  --> $DIR/issue-50480.rs:3:27
-   |
-LL | struct Foo(N, NotDefined, <i32 as Iterator>::Item, Vec<i32>, String);
-   |                           ^^^^^^^^^^^^^^^^^^^^^^^ `i32` is not an iterator
-   |
-   = help: the trait `Iterator` is not implemented for `i32`
-   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
-
 error[E0204]: the trait `Copy` may not be implemented for this type
   --> $DIR/issue-50480.rs:1:17
    |
@@ -82,17 +73,8 @@ LL | struct Foo(N, NotDefined, <i32 as Iterator>::Item, Vec<i32>, String);
    |
    = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error[E0277]: `i32` is not an iterator
-  --> $DIR/issue-50480.rs:12:33
-   |
-LL | struct Bar<T>(T, N, NotDefined, <i32 as Iterator>::Item, Vec<i32>, String);
-   |                                 ^^^^^^^^^^^^^^^^^^^^^^^ `i32` is not an iterator
-   |
-   = help: the trait `Iterator` is not implemented for `i32`
-   = note: if you want to iterate between `start` until a value `end`, use the exclusive range syntax `start..end` or the inclusive range syntax `start..=end`
-
 error[E0204]: the trait `Copy` may not be implemented for this type
-  --> $DIR/issue-50480.rs:10:17
+  --> $DIR/issue-50480.rs:9:17
    |
 LL | #[derive(Clone, Copy)]
    |                 ^^^^
@@ -104,7 +86,7 @@ LL | struct Bar<T>(T, N, NotDefined, <i32 as Iterator>::Item, Vec<i32>, String);
    |
    = note: this error originates in the derive macro `Copy` (in Nightly builds, run with -Z macro-backtrace for more info)
 
-error: aborting due to 10 previous errors
+error: aborting due to 8 previous errors
 
-Some errors have detailed explanations: E0204, E0277, E0412.
+Some errors have detailed explanations: E0204, E0412.
 For more information about an error, try `rustc --explain E0204`.
diff --git a/tests/ui/traits/new-solver/fn-trait-closure.rs b/tests/ui/traits/new-solver/fn-trait-closure.rs
new file mode 100644
index 00000000000..c0ecf1c91fb
--- /dev/null
+++ b/tests/ui/traits/new-solver/fn-trait-closure.rs
@@ -0,0 +1,15 @@
+// compile-flags: -Ztrait-solver=next
+// known-bug: unknown
+// failure-status: 101
+// dont-check-compiler-stderr
+
+// This test will fail until we fix `FulfillmentCtxt::relationships`. That's
+// because we create a type variable for closure upvar types, which is not
+// constrained until after we try to do fallback on diverging type variables.
+// Thus, we will call that function, which is unimplemented.
+
+fn require_fn(_: impl Fn() -> i32) {}
+
+fn main() {
+    require_fn(|| -> i32 { 1i32 });
+}
diff --git a/tests/ui/traits/new-solver/fn-trait.rs b/tests/ui/traits/new-solver/fn-trait.rs
new file mode 100644
index 00000000000..d566ead105c
--- /dev/null
+++ b/tests/ui/traits/new-solver/fn-trait.rs
@@ -0,0 +1,13 @@
+// compile-flags: -Ztrait-solver=next
+// check-pass
+
+fn require_fn(_: impl Fn() -> i32) {}
+
+fn f() -> i32 {
+    1i32
+}
+
+fn main() {
+    require_fn(f);
+    require_fn(f as fn() -> i32);
+}
diff --git a/tests/ui/traits/new-solver/pointer-sized.rs b/tests/ui/traits/new-solver/pointer-sized.rs
new file mode 100644
index 00000000000..15681cd132e
--- /dev/null
+++ b/tests/ui/traits/new-solver/pointer-sized.rs
@@ -0,0 +1,12 @@
+#![feature(pointer_sized_trait)]
+
+use std::marker::PointerSized;
+
+fn require_pointer_sized(_: impl PointerSized) {}
+
+fn main() {
+    require_pointer_sized(1usize);
+    require_pointer_sized(1u16);
+    //~^ ERROR `u16` needs to be a pointer-sized type
+    require_pointer_sized(&1i16);
+}
diff --git a/tests/ui/traits/new-solver/pointer-sized.stderr b/tests/ui/traits/new-solver/pointer-sized.stderr
new file mode 100644
index 00000000000..b250b1331bb
--- /dev/null
+++ b/tests/ui/traits/new-solver/pointer-sized.stderr
@@ -0,0 +1,24 @@
+error[E0277]: `u16` needs to be a pointer-sized type
+  --> $DIR/pointer-sized.rs:9:27
+   |
+LL |     require_pointer_sized(1u16);
+   |     --------------------- ^^^^ the trait `PointerSized` is not implemented for `u16`
+   |     |
+   |     required by a bound introduced by this call
+   |
+   = note: the trait bound `u16: PointerSized` is not satisfied
+note: required by a bound in `require_pointer_sized`
+  --> $DIR/pointer-sized.rs:5:34
+   |
+LL | fn require_pointer_sized(_: impl PointerSized) {}
+   |                                  ^^^^^^^^^^^^ required by this bound in `require_pointer_sized`
+help: consider borrowing here
+   |
+LL |     require_pointer_sized(&1u16);
+   |                           +
+LL |     require_pointer_sized(&mut 1u16);
+   |                           ++++
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0277`.
diff --git a/tests/ui/type-alias-impl-trait/bound_reduction2.rs b/tests/ui/type-alias-impl-trait/bound_reduction2.rs
index 4d2890b5de5..0bcc9e002ca 100644
--- a/tests/ui/type-alias-impl-trait/bound_reduction2.rs
+++ b/tests/ui/type-alias-impl-trait/bound_reduction2.rs
@@ -14,5 +14,5 @@ impl<W> Trait<W> for () {}
 
 fn foo_desugared<T: TraitWithAssoc>(_: T) -> Foo<T::Assoc> {
     ()
-    //~^ ERROR non-defining opaque type use
+    //~^ ERROR expected generic type parameter, found `<T as TraitWithAssoc>::Assoc`
 }
diff --git a/tests/ui/type-alias-impl-trait/bound_reduction2.stderr b/tests/ui/type-alias-impl-trait/bound_reduction2.stderr
index c405b1f6af2..3c259bd9e97 100644
--- a/tests/ui/type-alias-impl-trait/bound_reduction2.stderr
+++ b/tests/ui/type-alias-impl-trait/bound_reduction2.stderr
@@ -1,14 +1,12 @@
-error: non-defining opaque type use in defining scope
+error[E0792]: expected generic type parameter, found `<T as TraitWithAssoc>::Assoc`
   --> $DIR/bound_reduction2.rs:16:5
    |
+LL | type Foo<V> = impl Trait<V>;
+   |          - this generic parameter must be used with a generic type parameter
+...
 LL |     ()
    |     ^^
-   |
-note: used non-generic type `<T as TraitWithAssoc>::Assoc` for generic parameter
-  --> $DIR/bound_reduction2.rs:9:10
-   |
-LL | type Foo<V> = impl Trait<V>;
-   |          ^
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0792`.
diff --git a/tests/ui/type-alias-impl-trait/generic_nondefining_use.rs b/tests/ui/type-alias-impl-trait/generic_nondefining_use.rs
index f39741a6a62..f5045d382aa 100644
--- a/tests/ui/type-alias-impl-trait/generic_nondefining_use.rs
+++ b/tests/ui/type-alias-impl-trait/generic_nondefining_use.rs
@@ -10,12 +10,11 @@ type OneLifetime<'a> = impl Debug;
 
 type OneConst<const X: usize> = impl Debug;
 
-
 // Not defining uses, because they doesn't define *all* possible generics.
 
 fn concrete_ty() -> OneTy<u32> {
     5u32
-    //~^ ERROR non-defining opaque type use in defining scope
+    //~^ ERROR expected generic type parameter, found `u32`
 }
 
 fn concrete_lifetime() -> OneLifetime<'static> {
@@ -25,5 +24,5 @@ fn concrete_lifetime() -> OneLifetime<'static> {
 
 fn concrete_const() -> OneConst<{ 123 }> {
     7u32
-    //~^ ERROR non-defining opaque type use in defining scope
+    //~^ ERROR expected generic constant parameter, found `123`
 }
diff --git a/tests/ui/type-alias-impl-trait/generic_nondefining_use.stderr b/tests/ui/type-alias-impl-trait/generic_nondefining_use.stderr
index e7565525ad3..564648630b1 100644
--- a/tests/ui/type-alias-impl-trait/generic_nondefining_use.stderr
+++ b/tests/ui/type-alias-impl-trait/generic_nondefining_use.stderr
@@ -1,17 +1,14 @@
-error: non-defining opaque type use in defining scope
-  --> $DIR/generic_nondefining_use.rs:17:5
+error[E0792]: expected generic type parameter, found `u32`
+  --> $DIR/generic_nondefining_use.rs:16:5
    |
+LL | type OneTy<T> = impl Debug;
+   |            - this generic parameter must be used with a generic type parameter
+...
 LL |     5u32
    |     ^^^^
-   |
-note: used non-generic type `u32` for generic parameter
-  --> $DIR/generic_nondefining_use.rs:7:12
-   |
-LL | type OneTy<T> = impl Debug;
-   |            ^
 
 error: non-defining opaque type use in defining scope
-  --> $DIR/generic_nondefining_use.rs:22:5
+  --> $DIR/generic_nondefining_use.rs:21:5
    |
 LL | type OneLifetime<'a> = impl Debug;
    |                  -- cannot use static lifetime; use a bound lifetime instead or remove the lifetime parameter from the opaque type
@@ -19,17 +16,15 @@ LL | type OneLifetime<'a> = impl Debug;
 LL |     6u32
    |     ^^^^
 
-error: non-defining opaque type use in defining scope
-  --> $DIR/generic_nondefining_use.rs:27:5
+error[E0792]: expected generic constant parameter, found `123`
+  --> $DIR/generic_nondefining_use.rs:26:5
    |
+LL | type OneConst<const X: usize> = impl Debug;
+   |               -------------- this generic parameter must be used with a generic constant parameter
+...
 LL |     7u32
    |     ^^^^
-   |
-note: used non-generic constant `123` for generic parameter
-  --> $DIR/generic_nondefining_use.rs:11:15
-   |
-LL | type OneConst<const X: usize> = impl Debug;
-   |               ^^^^^^^^^^^^^^
 
 error: aborting due to 3 previous errors
 
+For more information about this error, try `rustc --explain E0792`.
diff --git a/tests/ui/type-alias-impl-trait/generic_type_does_not_live_long_enough.rs b/tests/ui/type-alias-impl-trait/generic_type_does_not_live_long_enough.rs
index cb90776472b..d3e169a70d3 100644
--- a/tests/ui/type-alias-impl-trait/generic_type_does_not_live_long_enough.rs
+++ b/tests/ui/type-alias-impl-trait/generic_type_does_not_live_long_enough.rs
@@ -4,7 +4,7 @@ fn main() {
     let y = 42;
     let x = wrong_generic(&y);
     let z: i32 = x;
-    //~^ ERROR non-defining opaque type use
+    //~^ ERROR expected generic type parameter, found `&'static i32
 }
 
 type WrongGeneric<T> = impl 'static;
diff --git a/tests/ui/type-alias-impl-trait/generic_type_does_not_live_long_enough.stderr b/tests/ui/type-alias-impl-trait/generic_type_does_not_live_long_enough.stderr
index ba583241a69..19115fd2866 100644
--- a/tests/ui/type-alias-impl-trait/generic_type_does_not_live_long_enough.stderr
+++ b/tests/ui/type-alias-impl-trait/generic_type_does_not_live_long_enough.stderr
@@ -4,17 +4,14 @@ error: at least one trait must be specified
 LL | type WrongGeneric<T> = impl 'static;
    |                        ^^^^^^^^^^^^
 
-error: non-defining opaque type use in defining scope
+error[E0792]: expected generic type parameter, found `&'static i32`
   --> $DIR/generic_type_does_not_live_long_enough.rs:6:18
    |
 LL |     let z: i32 = x;
    |                  ^
-   |
-note: used non-generic type `&'static i32` for generic parameter
-  --> $DIR/generic_type_does_not_live_long_enough.rs:10:19
-   |
+...
 LL | type WrongGeneric<T> = impl 'static;
-   |                   ^
+   |                   - this generic parameter must be used with a generic type parameter
 
 error[E0310]: the parameter type `T` may not live long enough
   --> $DIR/generic_type_does_not_live_long_enough.rs:14:5
@@ -29,4 +26,5 @@ LL | fn wrong_generic<T: 'static>(t: T) -> WrongGeneric<T> {
 
 error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0310`.
+Some errors have detailed explanations: E0310, E0792.
+For more information about an error, try `rustc --explain E0310`.
diff --git a/tests/ui/type-alias-impl-trait/issue-104817.rs b/tests/ui/type-alias-impl-trait/issue-104817.rs
new file mode 100644
index 00000000000..0d3bace4db1
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/issue-104817.rs
@@ -0,0 +1,19 @@
+#![feature(type_alias_impl_trait)]
+#![cfg_attr(specialized, feature(specialization))]
+#![allow(incomplete_features)]
+
+// revisions: stock specialized
+// [specialized]check-pass
+
+trait OpaqueTrait {}
+impl<T> OpaqueTrait for T {}
+type OpaqueType = impl OpaqueTrait;
+fn mk_opaque() -> OpaqueType {
+    || 0
+}
+trait AnotherTrait {}
+impl<T: Send> AnotherTrait for T {}
+impl AnotherTrait for OpaqueType {}
+//[stock]~^ conflicting implementations of trait `AnotherTrait` for type `OpaqueType`
+
+fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/issue-104817.stock.stderr b/tests/ui/type-alias-impl-trait/issue-104817.stock.stderr
new file mode 100644
index 00000000000..47bae8bd12b
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/issue-104817.stock.stderr
@@ -0,0 +1,11 @@
+error[E0119]: conflicting implementations of trait `AnotherTrait` for type `OpaqueType`
+  --> $DIR/issue-104817.rs:16:1
+   |
+LL | impl<T: Send> AnotherTrait for T {}
+   | -------------------------------- first implementation here
+LL | impl AnotherTrait for OpaqueType {}
+   | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ conflicting implementation for `OpaqueType`
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0119`.
diff --git a/tests/ui/type-alias-impl-trait/issue-53092-2.rs b/tests/ui/type-alias-impl-trait/issue-53092-2.rs
index 438ac35fdea..057930f0c1c 100644
--- a/tests/ui/type-alias-impl-trait/issue-53092-2.rs
+++ b/tests/ui/type-alias-impl-trait/issue-53092-2.rs
@@ -4,7 +4,6 @@
 type Bug<T, U> = impl Fn(T) -> U + Copy; //~ ERROR cycle detected
 
 const CONST_BUG: Bug<u8, ()> = unsafe { std::mem::transmute(|_: u8| ()) };
-//~^ ERROR: cannot transmute
 
 fn make_bug<T, U: From<T>>() -> Bug<T, U> {
     |x| x.into() //~ ERROR the trait bound `U: From<T>` is not satisfied
diff --git a/tests/ui/type-alias-impl-trait/issue-53092-2.stderr b/tests/ui/type-alias-impl-trait/issue-53092-2.stderr
index 1b89d55711d..2565a28b493 100644
--- a/tests/ui/type-alias-impl-trait/issue-53092-2.stderr
+++ b/tests/ui/type-alias-impl-trait/issue-53092-2.stderr
@@ -24,23 +24,14 @@ LL | |     CONST_BUG(0);
 LL | | }
    | |_^
 
-error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
-  --> $DIR/issue-53092-2.rs:6:41
-   |
-LL | const CONST_BUG: Bug<u8, ()> = unsafe { std::mem::transmute(|_: u8| ()) };
-   |                                         ^^^^^^^^^^^^^^^^^^^
-   |
-   = note: source type: `[closure@$DIR/issue-53092-2.rs:6:61: 6:68]` (0 bits)
-   = note: target type: `Bug<u8, ()>` (size can vary because of [type error])
-
 error[E0277]: the trait bound `U: From<T>` is not satisfied
-  --> $DIR/issue-53092-2.rs:10:5
+  --> $DIR/issue-53092-2.rs:9:5
    |
 LL |     |x| x.into()
    |     ^^^^^^^^^^^^ the trait `From<T>` is not implemented for `U`
    |
 note: required by a bound in `make_bug`
-  --> $DIR/issue-53092-2.rs:9:19
+  --> $DIR/issue-53092-2.rs:8:19
    |
 LL | fn make_bug<T, U: From<T>>() -> Bug<T, U> {
    |                   ^^^^^^^ required by this bound in `make_bug`
@@ -49,7 +40,7 @@ help: consider restricting type parameter `U`
 LL | type Bug<T, U: std::convert::From<T>> = impl Fn(T) -> U + Copy;
    |              +++++++++++++++++++++++
 
-error: aborting due to 3 previous errors
+error: aborting due to 2 previous errors
 
-Some errors have detailed explanations: E0277, E0391, E0512.
+Some errors have detailed explanations: E0277, E0391.
 For more information about an error, try `rustc --explain E0277`.
diff --git a/tests/ui/type-alias-impl-trait/issue-60564.rs b/tests/ui/type-alias-impl-trait/issue-60564.rs
index 4fc7679311a..c2f4c370807 100644
--- a/tests/ui/type-alias-impl-trait/issue-60564.rs
+++ b/tests/ui/type-alias-impl-trait/issue-60564.rs
@@ -18,7 +18,7 @@ where
     type BitsIter = IterBitsIter<T, E, u8>;
     fn iter_bits(self, n: u8) -> Self::BitsIter {
         (0u8..n).rev().map(move |shift| ((self >> T::from(shift)) & T::from(1)).try_into().unwrap())
-        //~^ ERROR non-defining opaque type use in defining scope
+        //~^ ERROR expected generic type parameter, found `u8`
     }
 }
 
diff --git a/tests/ui/type-alias-impl-trait/issue-60564.stderr b/tests/ui/type-alias-impl-trait/issue-60564.stderr
index bbc93657be3..f8fdb004d09 100644
--- a/tests/ui/type-alias-impl-trait/issue-60564.stderr
+++ b/tests/ui/type-alias-impl-trait/issue-60564.stderr
@@ -1,14 +1,12 @@
-error: non-defining opaque type use in defining scope
+error[E0792]: expected generic type parameter, found `u8`
   --> $DIR/issue-60564.rs:20:9
    |
+LL | type IterBitsIter<T, E, I> = impl std::iter::Iterator<Item = I>;
+   |                         - this generic parameter must be used with a generic type parameter
+...
 LL |         (0u8..n).rev().map(move |shift| ((self >> T::from(shift)) & T::from(1)).try_into().unwrap())
    |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   |
-note: used non-generic type `u8` for generic parameter
-  --> $DIR/issue-60564.rs:8:25
-   |
-LL | type IterBitsIter<T, E, I> = impl std::iter::Iterator<Item = I>;
-   |                         ^
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0792`.
diff --git a/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use-2.rs b/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use-2.rs
index 5223fb1c702..5e0a82a7286 100644
--- a/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use-2.rs
+++ b/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use-2.rs
@@ -7,7 +7,7 @@ trait Trait<T> {}
 type Alias<'a, U> = impl Trait<U>;
 
 fn f<'a>() -> Alias<'a, ()> {}
-//~^ ERROR non-defining opaque type use in defining scope
+//~^ ERROR expected generic type parameter, found `()`
 
 fn main() {}
 
diff --git a/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use-2.stderr b/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use-2.stderr
index 7fb9a0c410e..271743a4010 100644
--- a/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use-2.stderr
+++ b/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use-2.stderr
@@ -1,14 +1,12 @@
-error: non-defining opaque type use in defining scope
+error[E0792]: expected generic type parameter, found `()`
   --> $DIR/issue-68368-non-defining-use-2.rs:9:29
    |
+LL | type Alias<'a, U> = impl Trait<U>;
+   |                - this generic parameter must be used with a generic type parameter
+LL |
 LL | fn f<'a>() -> Alias<'a, ()> {}
    |                             ^^
-   |
-note: used non-generic type `()` for generic parameter
-  --> $DIR/issue-68368-non-defining-use-2.rs:7:16
-   |
-LL | type Alias<'a, U> = impl Trait<U>;
-   |                ^
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0792`.
diff --git a/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use.rs b/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use.rs
index b50462bf237..3b32260c96f 100644
--- a/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use.rs
+++ b/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use.rs
@@ -7,7 +7,7 @@ trait Trait<T> {}
 type Alias<'a, U> = impl Trait<U>;
 
 fn f<'a>() -> Alias<'a, ()> {}
-//~^ ERROR non-defining opaque type use in defining scope
+//~^ ERROR expected generic type parameter, found `()`
 
 fn main() {}
 
diff --git a/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use.stderr b/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use.stderr
index 8059621b61a..4d9a8d6eef9 100644
--- a/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use.stderr
+++ b/tests/ui/type-alias-impl-trait/issue-68368-non-defining-use.stderr
@@ -1,14 +1,12 @@
-error: non-defining opaque type use in defining scope
+error[E0792]: expected generic type parameter, found `()`
   --> $DIR/issue-68368-non-defining-use.rs:9:29
    |
+LL | type Alias<'a, U> = impl Trait<U>;
+   |                - this generic parameter must be used with a generic type parameter
+LL |
 LL | fn f<'a>() -> Alias<'a, ()> {}
    |                             ^^
-   |
-note: used non-generic type `()` for generic parameter
-  --> $DIR/issue-68368-non-defining-use.rs:7:16
-   |
-LL | type Alias<'a, U> = impl Trait<U>;
-   |                ^
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0792`.
diff --git a/tests/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-error.rs b/tests/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-error.rs
index 428454bc048..7657fe2fb1a 100644
--- a/tests/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-error.rs
+++ b/tests/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-error.rs
@@ -18,6 +18,6 @@ type Return<A> = impl WithAssoc<A, AssocType = impl SomeTrait + 'a>;
 //~^ ERROR use of undeclared lifetime name `'a`
 
 fn my_fun() -> Return<()> {}
-//~^ ERROR non-defining opaque type use in defining scope
+//~^ ERROR expected generic type parameter, found `()`
 
 fn main() {}
diff --git a/tests/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-error.stderr b/tests/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-error.stderr
index 7b50c8af26e..d1250786d93 100644
--- a/tests/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-error.stderr
+++ b/tests/ui/type-alias-impl-trait/issue-69136-inner-lifetime-resolve-error.stderr
@@ -14,18 +14,16 @@ help: consider introducing lifetime `'a` here
 LL | type Return<'a, A> = impl WithAssoc<A, AssocType = impl SomeTrait + 'a>;
    |             +++
 
-error: non-defining opaque type use in defining scope
+error[E0792]: expected generic type parameter, found `()`
   --> $DIR/issue-69136-inner-lifetime-resolve-error.rs:20:27
    |
+LL | type Return<A> = impl WithAssoc<A, AssocType = impl SomeTrait + 'a>;
+   |             - this generic parameter must be used with a generic type parameter
+...
 LL | fn my_fun() -> Return<()> {}
    |                           ^^
-   |
-note: used non-generic type `()` for generic parameter
-  --> $DIR/issue-69136-inner-lifetime-resolve-error.rs:17:13
-   |
-LL | type Return<A> = impl WithAssoc<A, AssocType = impl SomeTrait + 'a>;
-   |             ^
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0261`.
+Some errors have detailed explanations: E0261, E0792.
+For more information about an error, try `rustc --explain E0261`.
diff --git a/tests/ui/type-alias-impl-trait/no_inferrable_concrete_type.rs b/tests/ui/type-alias-impl-trait/no_inferrable_concrete_type.rs
index 46621362e4f..0f0a02e97d8 100644
--- a/tests/ui/type-alias-impl-trait/no_inferrable_concrete_type.rs
+++ b/tests/ui/type-alias-impl-trait/no_inferrable_concrete_type.rs
@@ -15,5 +15,4 @@ mod foo {
 
 fn main() {
     let _: foo::Foo = std::mem::transmute(0u8);
-    //~^ ERROR cannot transmute between types of different sizes, or dependently-sized types
 }
diff --git a/tests/ui/type-alias-impl-trait/no_inferrable_concrete_type.stderr b/tests/ui/type-alias-impl-trait/no_inferrable_concrete_type.stderr
index 337708b8765..f3e8ae9c7db 100644
--- a/tests/ui/type-alias-impl-trait/no_inferrable_concrete_type.stderr
+++ b/tests/ui/type-alias-impl-trait/no_inferrable_concrete_type.stderr
@@ -6,15 +6,5 @@ LL |     pub type Foo = impl Copy;
    |
    = note: `Foo` must be used in combination with a concrete type within the same module
 
-error[E0512]: cannot transmute between types of different sizes, or dependently-sized types
-  --> $DIR/no_inferrable_concrete_type.rs:17:23
-   |
-LL |     let _: foo::Foo = std::mem::transmute(0u8);
-   |                       ^^^^^^^^^^^^^^^^^^^
-   |
-   = note: source type: `u8` (8 bits)
-   = note: target type: `Foo` (size can vary because of [type error])
-
-error: aborting due to 2 previous errors
+error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0512`.
diff --git a/tests/ui/type-alias-impl-trait/outlives-bound-var.rs b/tests/ui/type-alias-impl-trait/outlives-bound-var.rs
new file mode 100644
index 00000000000..b8fac45b76d
--- /dev/null
+++ b/tests/ui/type-alias-impl-trait/outlives-bound-var.rs
@@ -0,0 +1,18 @@
+// Here we process outlive obligations involving
+// opaque types with bound vars in substs.
+// This was an ICE.
+//
+// check-pass
+#![feature(type_alias_impl_trait)]
+
+type Ty<'a> = impl Sized + 'a;
+fn define<'a>() -> Ty<'a> {}
+
+// Ty<'^0>: 'static
+fn test1(_: &'static fn(Ty<'_>)) {}
+
+fn test2() {
+    None::<&fn(Ty<'_>)>;
+}
+
+fn main() { }
diff --git a/tests/ui/typeck/issue-104513-ice.stderr b/tests/ui/typeck/issue-104513-ice.stderr
index 5561673f3c6..42cfe38aed8 100644
--- a/tests/ui/typeck/issue-104513-ice.stderr
+++ b/tests/ui/typeck/issue-104513-ice.stderr
@@ -3,11 +3,6 @@ error[E0405]: cannot find trait `Oops` in this scope
    |
 LL |     let _: S<impl Oops> = S;
    |                   ^^^^ not found in this scope
-   |
-help: you might be missing a type parameter
-   |
-LL | fn f<Oops>() {
-   |     ++++++
 
 error[E0562]: `impl Trait` only allowed in function and inherent method return types, not in variable binding
   --> $DIR/issue-104513-ice.rs:3:14
diff --git a/tests/ui/unresolved/unresolved-candidates.stderr b/tests/ui/unresolved/unresolved-candidates.stderr
index bbd3eec2a54..ea737c567b9 100644
--- a/tests/ui/unresolved/unresolved-candidates.stderr
+++ b/tests/ui/unresolved/unresolved-candidates.stderr
@@ -7,7 +7,7 @@ LL |     use Trait;
 help: consider importing this trait instead
    |
 LL |     use a::Trait;
-   |         ~~~~~~~~~
+   |         ~~~~~~~~
 
 error[E0405]: cannot find trait `Trait` in this scope
   --> $DIR/unresolved-candidates.rs:10:10
diff --git a/tests/ui/variance/variance-associated-consts.stderr b/tests/ui/variance/variance-associated-consts.stderr
index f9732d02cb2..4df2d8da3d6 100644
--- a/tests/ui/variance/variance-associated-consts.stderr
+++ b/tests/ui/variance/variance-associated-consts.stderr
@@ -1,4 +1,4 @@
-error[E0208]: [o]
+error: [o]
   --> $DIR/variance-associated-consts.rs:13:1
    |
 LL | struct Foo<T: Trait> {
@@ -6,4 +6,3 @@ LL | struct Foo<T: Trait> {
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0208`.
diff --git a/tests/ui/variance/variance-associated-types.stderr b/tests/ui/variance/variance-associated-types.stderr
index 5ce62884e1d..51f17c7c228 100644
--- a/tests/ui/variance/variance-associated-types.stderr
+++ b/tests/ui/variance/variance-associated-types.stderr
@@ -1,10 +1,10 @@
-error[E0208]: [-, +]
+error: [-, +]
   --> $DIR/variance-associated-types.rs:13:1
    |
 LL | struct Foo<'a, T : Trait<'a>> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [o, o]
+error: [o, o]
   --> $DIR/variance-associated-types.rs:18:1
    |
 LL | struct Bar<'a, T : Trait<'a>> {
@@ -12,4 +12,3 @@ LL | struct Bar<'a, T : Trait<'a>> {
 
 error: aborting due to 2 previous errors
 
-For more information about this error, try `rustc --explain E0208`.
diff --git a/tests/ui/variance/variance-object-types.stderr b/tests/ui/variance/variance-object-types.stderr
index 1c3c1a6d1f2..55a760425ee 100644
--- a/tests/ui/variance/variance-object-types.stderr
+++ b/tests/ui/variance/variance-object-types.stderr
@@ -1,4 +1,4 @@
-error[E0208]: [o]
+error: [o]
   --> $DIR/variance-object-types.rs:7:1
    |
 LL | struct Foo<'a> {
@@ -6,4 +6,3 @@ LL | struct Foo<'a> {
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0208`.
diff --git a/tests/ui/variance/variance-regions-direct.stderr b/tests/ui/variance/variance-regions-direct.stderr
index 27d69b6e825..eda02e9b03b 100644
--- a/tests/ui/variance/variance-regions-direct.stderr
+++ b/tests/ui/variance/variance-regions-direct.stderr
@@ -1,40 +1,40 @@
-error[E0208]: [-, -, -]
+error: [-, -, -]
   --> $DIR/variance-regions-direct.rs:9:1
    |
 LL | struct Test2<'a, 'b, 'c> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [+, +, +]
+error: [+, +, +]
   --> $DIR/variance-regions-direct.rs:18:1
    |
 LL | struct Test3<'a, 'b, 'c> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [-, o]
+error: [-, o]
   --> $DIR/variance-regions-direct.rs:27:1
    |
 LL | struct Test4<'a, 'b:'a> {
    | ^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [+, o]
+error: [+, o]
   --> $DIR/variance-regions-direct.rs:35:1
    |
 LL | struct Test5<'a, 'b:'a> {
    | ^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [-, o]
+error: [-, o]
   --> $DIR/variance-regions-direct.rs:45:1
    |
 LL | struct Test6<'a, 'b:'a> {
    | ^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [*]
+error: [*]
   --> $DIR/variance-regions-direct.rs:52:1
    |
 LL | struct Test7<'a> {
    | ^^^^^^^^^^^^^^^^
 
-error[E0208]: [+, -, o]
+error: [+, -, o]
   --> $DIR/variance-regions-direct.rs:59:1
    |
 LL | enum Test8<'a, 'b, 'c:'b> {
@@ -42,4 +42,3 @@ LL | enum Test8<'a, 'b, 'c:'b> {
 
 error: aborting due to 7 previous errors
 
-For more information about this error, try `rustc --explain E0208`.
diff --git a/tests/ui/variance/variance-regions-indirect.stderr b/tests/ui/variance/variance-regions-indirect.stderr
index 535e97db3fb..fa2f4d507f3 100644
--- a/tests/ui/variance/variance-regions-indirect.stderr
+++ b/tests/ui/variance/variance-regions-indirect.stderr
@@ -1,28 +1,28 @@
-error[E0208]: [+, -, o, *]
+error: [+, -, o, *]
   --> $DIR/variance-regions-indirect.rs:8:1
    |
 LL | enum Base<'a, 'b, 'c:'b, 'd> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [*, o, -, +]
+error: [*, o, -, +]
   --> $DIR/variance-regions-indirect.rs:15:1
    |
 LL | struct Derived1<'w, 'x:'y, 'y, 'z> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [o, o, *]
+error: [o, o, *]
   --> $DIR/variance-regions-indirect.rs:20:1
    |
 LL | struct Derived2<'a, 'b:'a, 'c> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [o, -, *]
+error: [o, -, *]
   --> $DIR/variance-regions-indirect.rs:25:1
    |
 LL | struct Derived3<'a:'b, 'b, 'c> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [+, -, o]
+error: [+, -, o]
   --> $DIR/variance-regions-indirect.rs:30:1
    |
 LL | struct Derived4<'a, 'b, 'c:'b> {
@@ -30,4 +30,3 @@ LL | struct Derived4<'a, 'b, 'c:'b> {
 
 error: aborting due to 5 previous errors
 
-For more information about this error, try `rustc --explain E0208`.
diff --git a/tests/ui/variance/variance-trait-bounds.stderr b/tests/ui/variance/variance-trait-bounds.stderr
index 3f6ca62a640..5a73e541c3a 100644
--- a/tests/ui/variance/variance-trait-bounds.stderr
+++ b/tests/ui/variance/variance-trait-bounds.stderr
@@ -1,22 +1,22 @@
-error[E0208]: [+, +]
+error: [+, +]
   --> $DIR/variance-trait-bounds.rs:16:1
    |
 LL | struct TestStruct<U,T:Setter<U>> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [*, +]
+error: [*, +]
   --> $DIR/variance-trait-bounds.rs:21:1
    |
 LL | enum TestEnum<U,T:Setter<U>> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [*, +]
+error: [*, +]
   --> $DIR/variance-trait-bounds.rs:26:1
    |
 LL | struct TestContraStruct<U,T:Setter<U>> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [*, +]
+error: [*, +]
   --> $DIR/variance-trait-bounds.rs:31:1
    |
 LL | struct TestBox<U,T:Getter<U>+Setter<U>> {
@@ -24,4 +24,3 @@ LL | struct TestBox<U,T:Getter<U>+Setter<U>> {
 
 error: aborting due to 4 previous errors
 
-For more information about this error, try `rustc --explain E0208`.
diff --git a/tests/ui/variance/variance-trait-object-bound.stderr b/tests/ui/variance/variance-trait-object-bound.stderr
index 9a2c924b96a..7c46b553f43 100644
--- a/tests/ui/variance/variance-trait-object-bound.stderr
+++ b/tests/ui/variance/variance-trait-object-bound.stderr
@@ -1,4 +1,4 @@
-error[E0208]: [-]
+error: [-]
   --> $DIR/variance-trait-object-bound.rs:14:1
    |
 LL | struct TOption<'a> {
@@ -6,4 +6,3 @@ LL | struct TOption<'a> {
 
 error: aborting due to previous error
 
-For more information about this error, try `rustc --explain E0208`.
diff --git a/tests/ui/variance/variance-types-bounds.stderr b/tests/ui/variance/variance-types-bounds.stderr
index 523763b8a07..bb816443476 100644
--- a/tests/ui/variance/variance-types-bounds.stderr
+++ b/tests/ui/variance/variance-types-bounds.stderr
@@ -1,28 +1,28 @@
-error[E0208]: [+, +]
+error: [+, +]
   --> $DIR/variance-types-bounds.rs:7:1
    |
 LL | struct TestImm<A, B> {
    | ^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [+, o]
+error: [+, o]
   --> $DIR/variance-types-bounds.rs:13:1
    |
 LL | struct TestMut<A, B:'static> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [+, o]
+error: [+, o]
   --> $DIR/variance-types-bounds.rs:19:1
    |
 LL | struct TestIndirect<A:'static, B:'static> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [o, o]
+error: [o, o]
   --> $DIR/variance-types-bounds.rs:24:1
    |
 LL | struct TestIndirect2<A:'static, B:'static> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [o, o]
+error: [o, o]
   --> $DIR/variance-types-bounds.rs:38:1
    |
 LL | struct TestObject<A, R> {
@@ -30,4 +30,3 @@ LL | struct TestObject<A, R> {
 
 error: aborting due to 5 previous errors
 
-For more information about this error, try `rustc --explain E0208`.
diff --git a/tests/ui/variance/variance-types.stderr b/tests/ui/variance/variance-types.stderr
index 5a5aaecffc5..9f7f1d9b0e3 100644
--- a/tests/ui/variance/variance-types.stderr
+++ b/tests/ui/variance/variance-types.stderr
@@ -1,34 +1,34 @@
-error[E0208]: [-, o, o]
+error: [-, o, o]
   --> $DIR/variance-types.rs:10:1
    |
 LL | struct InvariantMut<'a,A:'a,B:'a> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [o]
+error: [o]
   --> $DIR/variance-types.rs:15:1
    |
 LL | struct InvariantCell<A> {
    | ^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [o]
+error: [o]
   --> $DIR/variance-types.rs:20:1
    |
 LL | struct InvariantIndirect<A> {
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [+]
+error: [+]
   --> $DIR/variance-types.rs:25:1
    |
 LL | struct Covariant<A> {
    | ^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [-]
+error: [-]
   --> $DIR/variance-types.rs:30:1
    |
 LL | struct Contravariant<A> {
    | ^^^^^^^^^^^^^^^^^^^^^^^
 
-error[E0208]: [+, -, o]
+error: [+, -, o]
   --> $DIR/variance-types.rs:35:1
    |
 LL | enum Enum<A,B,C> {
@@ -36,4 +36,3 @@ LL | enum Enum<A,B,C> {
 
 error: aborting due to 6 previous errors
 
-For more information about this error, try `rustc --explain E0208`.
diff --git a/triagebot.toml b/triagebot.toml
index 14bade6472f..16a31321513 100644
--- a/triagebot.toml
+++ b/triagebot.toml
@@ -175,7 +175,7 @@ exclude_labels = [
     "T-*",
 ]
 
-[autolabel."A-bootstrap"]
+[autolabel."T-bootstrap"]
 trigger_files = [
     "x.py",
     "x",
@@ -185,7 +185,6 @@ trigger_files = [
     "src/tools/x",
     "configure",
     "Cargo.toml",
-    "Cargo.lock",
     "config.toml.example",
     "src/stage0.json"
 ]
@@ -494,6 +493,8 @@ libs = [
 ]
 bootstrap = [
     "@Mark-Simulacrum",
+    "@albertlarsan68",
+    "@ozkanonur",
 ]
 infra-ci = [
     "@Mark-Simulacrum",