Auto merge of #63395 - Centril:rollup-kt805cj, r=Centril

Rollup of 6 pull requests

Successful merges:

 - #63162 (Miri tests: use xargo to build separate libstd)
 - #63289 (Don't recommend `extern crate` syntax)
 - #63373 (gitignore: add comment explaining policy)
 - #63374 (move of packed fields might or might not occur when they actually are sufficiently aligned)
 - #63381 (reduce visibility)
 - #63387 (Test interaction between `async { ... }` and `?`, `return`, and `break`)

Failed merges:

r? @ghost

35 files changed, 278 insertions, 160 deletions

diff --git a/.gitignore b/.gitignore
index b53b06b03ca..a0b491f4278 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,7 @@
+# This file should only ignore things that are generated during a build,
+# generated by common IDEs, and optional files controlled by the user
+# that affect the build (such as config.toml).
+# FIXME: This needs cleanup.
 *~
 .#*
 .DS_Store
@@ -14,20 +18,16 @@ __pycache__/
 .valgrindrc
 .vscode
 .favorites.json
-/*-*-*-*/
-/*-*-*/
 /Makefile
-/build
+/build/
 /config.toml
 /dist/
 /dl/
-/doc
+/doc/
 /inst/
 /llvm/
 /mingw-build/
-/nd/
 /obj/
-/rt/
 /rustllvm/
 /src/libcore/unicode/DerivedCoreProperties.txt
 /src/libcore/unicode/DerivedNormalizationProps.txt
@@ -37,11 +37,7 @@ __pycache__/
 /src/libcore/unicode/SpecialCasing.txt
 /src/libcore/unicode/UnicodeData.txt
 /src/libcore/unicode/downloaded
-/stage[0-9]+/
-/target
-target/
-/test/
-/tmp/
+/target/
 tags
 tags.*
 TAGS
@@ -50,17 +46,6 @@ TAGS.*
 \#*\#
 config.mk
 config.stamp
-keywords.md
-lexer.ml
 Session.vim
-src/etc/dl
-tmp.*.rs
-version.md
-version.ml
-version.texi
 .cargo
-!src/vendor/**
-/src/target/
-
 no_llvm_build
-
diff --git a/config.toml.example b/config.toml.example
index 6816eaeaa94..cb9f388a8e4 100644
--- a/config.toml.example
+++ b/config.toml.example
@@ -368,10 +368,6 @@
 # When creating source tarballs whether or not to create a source tarball.
 #dist-src = false
 
-# Whether to also run the Miri tests suite when running tests.
-# As a side-effect also generates MIR for all libraries.
-#test-miri = false
-
 # After building or testing extended tools (e.g. clippy and rustfmt), append the
 # result (broken, compiling, testing) into this JSON file.
 #save-toolstates = "/path/to/toolstates.json"
diff --git a/src/.gitignore b/src/.gitignore
deleted file mode 100644
index f1b36f58580..00000000000
--- a/src/.gitignore
+++ /dev/null
@@ -1,46 +0,0 @@
-*.a
-*.aux
-*.bc
-*.boot
-*.bz2
-*.cmi
-*.cmo
-*.cmx
-*.cp
-*.cps
-*.d
-*.dSYM
-*.def
-*.diff
-*.dll
-*.dylib
-*.elc
-*.epub
-*.exe
-*.fn
-*.html
-*.kdev4
-*.ky
-*.ll
-*.llvm
-*.log
-*.o
-*.orig
-*.out
-*.patch
-*.pdb
-*.pdf
-*.pg
-*.pot
-*.pyc
-*.rej
-*.rlib
-*.rustc
-*.so
-*.swo
-*.swp
-*.tmp
-*.toc
-*.tp
-*.vr
-*.x86
diff --git a/src/bootstrap/bin/rustc.rs b/src/bootstrap/bin/rustc.rs
index 23f81c2c876..54b689fb062 100644
--- a/src/bootstrap/bin/rustc.rs
+++ b/src/bootstrap/bin/rustc.rs
@@ -143,8 +143,11 @@ fn main() {
 
     if let Some(target) = target {
         // The stage0 compiler has a special sysroot distinct from what we
-        // actually downloaded, so we just always pass the `--sysroot` option.
-        cmd.arg("--sysroot").arg(&sysroot);
+        // actually downloaded, so we just always pass the `--sysroot` option,
+        // unless one is already set.
+        if !args.iter().any(|arg| arg == "--sysroot") {
+            cmd.arg("--sysroot").arg(&sysroot);
+        }
 
         cmd.arg("-Zexternal-macro-backtrace");
 
@@ -285,20 +288,6 @@ fn main() {
             }
         }
 
-        // When running miri tests, we need to generate MIR for all libraries
-        if env::var("TEST_MIRI").ok().map_or(false, |val| val == "true") {
-            // The flags here should be kept in sync with `add_miri_default_args`
-            // in miri's `src/lib.rs`.
-            cmd.arg("-Zalways-encode-mir");
-            cmd.arg("--cfg=miri");
-            // These options are preferred by miri, to be able to perform better validation,
-            // but the bootstrap compiler might not understand them.
-            if stage != "0" {
-                cmd.arg("-Zmir-emit-retag");
-                cmd.arg("-Zmir-opt-level=0");
-            }
-        }
-
         if let Ok(map) = env::var("RUSTC_DEBUGINFO_MAP") {
             cmd.arg("--remap-path-prefix").arg(&map);
         }
diff --git a/src/bootstrap/builder.rs b/src/bootstrap/builder.rs
index 5a75497173e..e54c9360bae 100644
--- a/src/bootstrap/builder.rs
+++ b/src/bootstrap/builder.rs
@@ -543,15 +543,6 @@ impl<'a> Builder<'a> {
             parent: Cell::new(None),
         };
 
-        if kind == Kind::Dist {
-            assert!(
-                !builder.config.test_miri,
-                "Do not distribute with miri enabled.\n\
-                The distributed libraries would include all MIR (increasing binary size).
-                The distributed MIR would include validation statements."
-            );
-        }
-
         builder
     }
 
@@ -981,7 +972,6 @@ impl<'a> Builder<'a> {
                     PathBuf::from("/path/to/nowhere/rustdoc/not/required")
                 },
             )
-            .env("TEST_MIRI", self.config.test_miri.to_string())
             .env("RUSTC_ERROR_METADATA_DST", self.extended_error_dir());
 
         if let Some(host_linker) = self.linker(compiler.host) {
diff --git a/src/bootstrap/config.rs b/src/bootstrap/config.rs
index 5a5f4ac7252..a5bfafdfdb4 100644
--- a/src/bootstrap/config.rs
+++ b/src/bootstrap/config.rs
@@ -128,7 +128,6 @@ pub struct Config {
     pub low_priority: bool,
     pub channel: String,
     pub verbose_tests: bool,
-    pub test_miri: bool,
     pub save_toolstates: Option<PathBuf>,
     pub print_step_timings: bool,
     pub missing_tools: bool,
@@ -315,7 +314,6 @@ struct Rust {
     debug: Option<bool>,
     dist_src: Option<bool>,
     verbose_tests: Option<bool>,
-    test_miri: Option<bool>,
     incremental: Option<bool>,
     save_toolstates: Option<String>,
     codegen_backends: Option<Vec<String>>,
@@ -375,7 +373,6 @@ impl Config {
         config.codegen_tests = true;
         config.ignore_git = false;
         config.rust_dist_src = true;
-        config.test_miri = false;
         config.rust_codegen_backends = vec![INTERNER.intern_str("llvm")];
         config.rust_codegen_backends_dir = "codegen-backends".to_owned();
         config.deny_warnings = true;
@@ -557,7 +554,6 @@ impl Config {
             set(&mut config.channel, rust.channel.clone());
             set(&mut config.rust_dist_src, rust.dist_src);
             set(&mut config.verbose_tests, rust.verbose_tests);
-            set(&mut config.test_miri, rust.test_miri);
             // in the case "false" is set explicitly, do not overwrite the command line args
             if let Some(true) = rust.incremental {
                 config.incremental = true;
diff --git a/src/bootstrap/configure.py b/src/bootstrap/configure.py
index 298330869b6..346f0cb2039 100755
--- a/src/bootstrap/configure.py
+++ b/src/bootstrap/configure.py
@@ -36,7 +36,6 @@ o("docs", "build.docs", "build standard library documentation")
 o("compiler-docs", "build.compiler-docs", "build compiler documentation")
 o("optimize-tests", "rust.optimize-tests", "build tests with optimizations")
 o("parallel-compiler", "rust.parallel-compiler", "build a multi-threaded rustc")
-o("test-miri", "rust.test-miri", "run miri's test suite")
 o("verbose-tests", "rust.verbose-tests", "enable verbose output when running tests")
 o("ccache", "llvm.ccache", "invoke gcc/clang via ccache to reuse object files between builds")
 o("sccache", None, "invoke gcc/clang via sccache to reuse object files between builds")
diff --git a/src/bootstrap/lib.rs b/src/bootstrap/lib.rs
index c8ea3157dc9..b72aa78f3de 100644
--- a/src/bootstrap/lib.rs
+++ b/src/bootstrap/lib.rs
@@ -540,9 +540,7 @@ impl Build {
             Mode::Rustc => "-rustc",
             Mode::Codegen => "-codegen",
             Mode::ToolBootstrap => "-bootstrap-tools",
-            Mode::ToolStd => "-tools",
-            Mode::ToolTest => "-tools",
-            Mode::ToolRustc => "-tools",
+            Mode::ToolStd | Mode::ToolTest | Mode::ToolRustc => "-tools",
         };
         self.out.join(&*compiler.host)
                 .join(format!("stage{}{}", compiler.stage, suffix))
diff --git a/src/bootstrap/test.rs b/src/bootstrap/test.rs
index e5b0a46ba6f..c2c134bfd1d 100644
--- a/src/bootstrap/test.rs
+++ b/src/bootstrap/test.rs
@@ -363,11 +363,9 @@ pub struct Miri {
 impl Step for Miri {
     type Output = ();
     const ONLY_HOSTS: bool = true;
-    const DEFAULT: bool = true;
 
     fn should_run(run: ShouldRun<'_>) -> ShouldRun<'_> {
-        let test_miri = run.builder.config.test_miri;
-        run.path("src/tools/miri").default_condition(test_miri)
+        run.path("src/tools/miri")
     }
 
     fn make_run(run: RunConfig<'_>) {
@@ -389,26 +387,92 @@ impl Step for Miri {
             extra_features: Vec::new(),
         });
         if let Some(miri) = miri {
-            let mut cargo = tool::prepare_tool_cargo(builder,
-                                                 compiler,
-                                                 Mode::ToolRustc,
-                                                 host,
-                                                 "test",
-                                                 "src/tools/miri",
-                                                 SourceType::Submodule,
-                                                 &[]);
+            // # Run `cargo miri setup`.
+            // As a side-effect, this will install xargo.
+            let mut cargo = tool::prepare_tool_cargo(
+                builder,
+                compiler,
+                Mode::ToolRustc,
+                host,
+                "run",
+                "src/tools/miri",
+                SourceType::Submodule,
+                &[],
+            );
+            cargo
+                .arg("--bin")
+                .arg("cargo-miri")
+                .arg("--")
+                .arg("miri")
+                .arg("setup");
+
+            // Tell `cargo miri` not to worry about the sysroot mismatch (we built with
+            // stage1 but run with stage2).
+            cargo.env("MIRI_SKIP_SYSROOT_CHECK", "1");
+            // Tell `cargo miri setup` where to find the sources.
+            cargo.env("XARGO_RUST_SRC", builder.src.join("src"));
+            // Debug things.
+            cargo.env("RUST_BACKTRACE", "1");
+            // Configure `cargo install` path, and let cargo-miri know that that's where
+            // xargo ends up.
+            cargo.env("CARGO_INSTALL_ROOT", &builder.out); // cargo adds a `bin/`
+            cargo.env("XARGO", builder.out.join("bin").join("xargo"));
+
+            if !try_run(builder, &mut cargo) {
+                return;
+            }
+
+            // # Determine where Miri put its sysroot.
+            // To this end, we run `cargo miri setup --env` and capture the output.
+            // (We do this separately from the above so that when the setup actually
+            // happens we get some output.)
+            // We re-use the `cargo` from above.
+            cargo.arg("--env");
+
+            // FIXME: Is there a way in which we can re-use the usual `run` helpers?
+            let miri_sysroot = if builder.config.dry_run {
+                String::new()
+            } else {
+                builder.verbose(&format!("running: {:?}", cargo));
+                let out = cargo.output()
+                    .expect("We already ran `cargo miri setup` before and that worked");
+                assert!(out.status.success(), "`cargo miri setup` returned with non-0 exit code");
+                // Output is "MIRI_SYSROOT=<str>\n".
+                let stdout = String::from_utf8(out.stdout)
+                    .expect("`cargo miri setup` stdout is not valid UTF-8");
+                let stdout = stdout.trim();
+                builder.verbose(&format!("`cargo miri setup --env` returned: {:?}", stdout));
+                let sysroot = stdout.splitn(2, '=')
+                    .nth(1).expect("`cargo miri setup` stdout did not contain '='");
+                sysroot.to_owned()
+            };
+
+            // # Run `cargo test`.
+            let mut cargo = tool::prepare_tool_cargo(
+                builder,
+                compiler,
+                Mode::ToolRustc,
+                host,
+                "test",
+                "src/tools/miri",
+                SourceType::Submodule,
+                &[],
+            );
 
             // miri tests need to know about the stage sysroot
-            cargo.env("MIRI_SYSROOT", builder.sysroot(compiler));
+            cargo.env("MIRI_SYSROOT", miri_sysroot);
             cargo.env("RUSTC_TEST_SUITE", builder.rustc(compiler));
             cargo.env("RUSTC_LIB_PATH", builder.rustc_libdir(compiler));
             cargo.env("MIRI_PATH", miri);
 
             builder.add_rustc_lib_path(compiler, &mut cargo);
 
-            if try_run(builder, &mut cargo) {
-                builder.save_toolstate("miri", ToolState::TestPass);
+            if !try_run(builder, &mut cargo) {
+                return;
             }
+
+            // # Done!
+            builder.save_toolstate("miri", ToolState::TestPass);
         } else {
             eprintln!("failed to test miri: could not build");
         }
diff --git a/src/ci/azure-pipelines/auto.yml b/src/ci/azure-pipelines/auto.yml
index 6ed1585c516..687856cca6b 100644
--- a/src/ci/azure-pipelines/auto.yml
+++ b/src/ci/azure-pipelines/auto.yml
@@ -254,7 +254,7 @@ jobs:
       x86_64-msvc-tools:
         MSYS_BITS: 64
         SCRIPT: src/ci/docker/x86_64-gnu-tools/checktools.sh x.py /tmp/toolstates.json windows
-        RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --save-toolstates=/tmp/toolstates.json --enable-test-miri
+        RUST_CONFIGURE_ARGS: --build=x86_64-pc-windows-msvc --save-toolstates=/tmp/toolstates.json
 
       # 32/64-bit MinGW builds.
       #
diff --git a/src/ci/docker/x86_64-gnu-tools/Dockerfile b/src/ci/docker/x86_64-gnu-tools/Dockerfile
index bab9145cbcb..f11ae7a34cb 100644
--- a/src/ci/docker/x86_64-gnu-tools/Dockerfile
+++ b/src/ci/docker/x86_64-gnu-tools/Dockerfile
@@ -23,6 +23,5 @@ COPY x86_64-gnu-tools/repo.sh /tmp/
 
 ENV RUST_CONFIGURE_ARGS \
   --build=x86_64-unknown-linux-gnu \
-  --enable-test-miri \
   --save-toolstates=/tmp/toolstates.json
 ENV SCRIPT /tmp/checktools.sh ../x.py /tmp/toolstates.json linux
diff --git a/src/libcore/pin.rs b/src/libcore/pin.rs
index 88a56174629..271ddcc4662 100644
--- a/src/libcore/pin.rs
+++ b/src/libcore/pin.rs
@@ -188,7 +188,8 @@
 //! you do not accidentally use `self`/`this` in a way that is in conflict with pinning.
 //!
 //! Moreover, if your type is `#[repr(packed)]`, the compiler will automatically
-//! move fields around to be able to drop them. As a consequence, you cannot use
+//! move fields around to be able to drop them. It might even do
+//! that for fields that happen to be sufficiently aligned. As a consequence, you cannot use
 //! pinning with a `#[repr(packed)]` type.
 //!
 //! # Projections and Structural Pinning
diff --git a/src/librustc_resolve/lib.rs b/src/librustc_resolve/lib.rs
index 2c56f5fb452..e7feccf5069 100644
--- a/src/librustc_resolve/lib.rs
+++ b/src/librustc_resolve/lib.rs
@@ -4084,7 +4084,7 @@ impl<'a> Resolver<'a> {
                                 )),
                             )
                         } else if !ident.is_reserved() {
-                            (format!("maybe a missing `extern crate {};`?", ident), None)
+                            (format!("maybe a missing crate `{}`?", ident), None)
                         } else {
                             // the parser will already have complained about the keyword being used
                             return PathResult::NonModule(PartialRes::new(Res::Err));
diff --git a/src/libsyntax/source_map.rs b/src/libsyntax/source_map.rs
index f83c1dbf7ee..4e29c77c89e 100644
--- a/src/libsyntax/source_map.rs
+++ b/src/libsyntax/source_map.rs
@@ -125,12 +125,12 @@ impl StableSourceFileId {
 
 #[derive(Default)]
 pub(super) struct SourceMapFiles {
-    pub(super) source_files: Vec<Lrc<SourceFile>>,
+    source_files: Vec<Lrc<SourceFile>>,
     stable_id_to_source_file: FxHashMap<StableSourceFileId, Lrc<SourceFile>>
 }
 
 pub struct SourceMap {
-    pub(super) files: Lock<SourceMapFiles>,
+    files: Lock<SourceMapFiles>,
     file_loader: Box<dyn FileLoader + Sync + Send>,
     // This is used to apply the file path remapping as specified via
     // --remap-path-prefix to all SourceFiles allocated within this SourceMap.
diff --git a/src/test/ui/async-await/async-block-control-flow-static-semantics.rs b/src/test/ui/async-await/async-block-control-flow-static-semantics.rs
new file mode 100644
index 00000000000..6a766ede0ed
--- /dev/null
+++ b/src/test/ui/async-await/async-block-control-flow-static-semantics.rs
@@ -0,0 +1,67 @@
+// Test that `async { .. }` blocks:
+// 1. do not allow `break` expressions.
+// 2. get targeted by `return` and not the parent function.
+// 3. get targeted by `?` and not the parent function.
+//
+// edition:2018
+// ignore-tidy-linelength
+
+#![feature(async_await)]
+
+fn main() {}
+
+use core::future::Future;
+
+fn return_targets_async_block_not_fn() -> u8 {
+    //~^ ERROR mismatched types
+    let block = async {
+        return 0u8;
+    };
+    let _: &dyn Future<Output = ()> = &block;
+    //~^ ERROR type mismatch resolving `<impl std::future::Future as std::future::Future>::Output == ()`
+}
+
+async fn return_targets_async_block_not_async_fn() -> u8 {
+    //~^ ERROR type mismatch resolving
+    let block = async {
+        return 0u8;
+    };
+    let _: &dyn Future<Output = ()> = &block;
+    //~^ ERROR type mismatch resolving `<impl std::future::Future as std::future::Future>::Output == ()`
+}
+
+fn no_break_in_async_block() {
+    async {
+        break 0u8; //~ ERROR `break` inside of a closure
+        // FIXME: This diagnostic is pretty bad.
+    };
+}
+
+fn no_break_in_async_block_even_with_outer_loop() {
+    loop {
+        async {
+            break 0u8; //~ ERROR `break` inside of a closure
+        };
+    }
+}
+
+struct MyErr;
+fn err() -> Result<u8, MyErr> { Err(MyErr) }
+
+fn rethrow_targets_async_block_not_fn() -> Result<u8, MyErr> {
+    //~^ ERROR mismatched types
+    let block = async {
+        err()?;
+        Ok(())
+    };
+    let _: &dyn Future<Output = Result<(), MyErr>> = &block;
+}
+
+fn rethrow_targets_async_block_not_async_fn() -> Result<u8, MyErr> {
+    //~^ ERROR mismatched types
+    let block = async {
+        err()?;
+        Ok(())
+    };
+    let _: &dyn Future<Output = Result<(), MyErr>> = &block;
+}
diff --git a/src/test/ui/async-await/async-block-control-flow-static-semantics.stderr b/src/test/ui/async-await/async-block-control-flow-static-semantics.stderr
new file mode 100644
index 00000000000..96927ac9632
--- /dev/null
+++ b/src/test/ui/async-await/async-block-control-flow-static-semantics.stderr
@@ -0,0 +1,79 @@
+error[E0267]: `break` inside of a closure
+  --> $DIR/async-block-control-flow-static-semantics.rs:35:9
+   |
+LL |         break 0u8;
+   |         ^^^^^^^^^ cannot break inside of a closure
+
+error[E0267]: `break` inside of a closure
+  --> $DIR/async-block-control-flow-static-semantics.rs:43:13
+   |
+LL |             break 0u8;
+   |             ^^^^^^^^^ cannot break inside of a closure
+
+error[E0308]: mismatched types
+  --> $DIR/async-block-control-flow-static-semantics.rs:15:43
+   |
+LL | fn return_targets_async_block_not_fn() -> u8 {
+   |    ---------------------------------      ^^ expected u8, found ()
+   |    |
+   |    this function's body doesn't return
+   |
+   = note: expected type `u8`
+              found type `()`
+
+error[E0271]: type mismatch resolving `<impl std::future::Future as std::future::Future>::Output == ()`
+  --> $DIR/async-block-control-flow-static-semantics.rs:20:39
+   |
+LL |     let _: &dyn Future<Output = ()> = &block;
+   |                                       ^^^^^^ expected u8, found ()
+   |
+   = note: expected type `u8`
+              found type `()`
+   = note: required for the cast to the object type `dyn std::future::Future<Output = ()>`
+
+error[E0271]: type mismatch resolving `<impl std::future::Future as std::future::Future>::Output == ()`
+  --> $DIR/async-block-control-flow-static-semantics.rs:29:39
+   |
+LL |     let _: &dyn Future<Output = ()> = &block;
+   |                                       ^^^^^^ expected u8, found ()
+   |
+   = note: expected type `u8`
+              found type `()`
+   = note: required for the cast to the object type `dyn std::future::Future<Output = ()>`
+
+error[E0271]: type mismatch resolving `<impl std::future::Future as std::future::Future>::Output == u8`
+  --> $DIR/async-block-control-flow-static-semantics.rs:24:55
+   |
+LL | async fn return_targets_async_block_not_async_fn() -> u8 {
+   |                                                       ^^ expected (), found u8
+   |
+   = note: expected type `()`
+              found type `u8`
+   = note: the return type of a function must have a statically known size
+
+error[E0308]: mismatched types
+  --> $DIR/async-block-control-flow-static-semantics.rs:51:44
+   |
+LL | fn rethrow_targets_async_block_not_fn() -> Result<u8, MyErr> {
+   |    ----------------------------------      ^^^^^^^^^^^^^^^^^ expected enum `std::result::Result`, found ()
+   |    |
+   |    this function's body doesn't return
+   |
+   = note: expected type `std::result::Result<u8, MyErr>`
+              found type `()`
+
+error[E0308]: mismatched types
+  --> $DIR/async-block-control-flow-static-semantics.rs:60:50
+   |
+LL | fn rethrow_targets_async_block_not_async_fn() -> Result<u8, MyErr> {
+   |    ----------------------------------------      ^^^^^^^^^^^^^^^^^ expected enum `std::result::Result`, found ()
+   |    |
+   |    this function's body doesn't return
+   |
+   = note: expected type `std::result::Result<u8, MyErr>`
+              found type `()`
+
+error: aborting due to 8 previous errors
+
+Some errors have detailed explanations: E0267, E0271, E0308.
+For more information about an error, try `rustc --explain E0267`.
diff --git a/src/test/ui/error-codes/E0432.stderr b/src/test/ui/error-codes/E0432.stderr
index 137a1af6f95..afb031c2252 100644
--- a/src/test/ui/error-codes/E0432.stderr
+++ b/src/test/ui/error-codes/E0432.stderr
@@ -2,7 +2,7 @@ error[E0432]: unresolved import `something`
   --> $DIR/E0432.rs:1:5
    |
 LL | use something::Foo;
-   |     ^^^^^^^^^ maybe a missing `extern crate something;`?
+   |     ^^^^^^^^^ maybe a missing crate `something`?
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/extern-prelude-fail.stderr b/src/test/ui/extern-prelude-fail.stderr
index 9cd56ea7f5b..a59f4c952bb 100644
--- a/src/test/ui/extern-prelude-fail.stderr
+++ b/src/test/ui/extern-prelude-fail.stderr
@@ -2,13 +2,13 @@ error[E0432]: unresolved import `extern_prelude`
   --> $DIR/extern-prelude-fail.rs:7:9
    |
 LL |     use extern_prelude::S;
-   |         ^^^^^^^^^^^^^^ maybe a missing `extern crate extern_prelude;`?
+   |         ^^^^^^^^^^^^^^ maybe a missing crate `extern_prelude`?
 
-error[E0433]: failed to resolve: maybe a missing `extern crate extern_prelude;`?
+error[E0433]: failed to resolve: maybe a missing crate `extern_prelude`?
   --> $DIR/extern-prelude-fail.rs:8:15
    |
 LL |     let s = ::extern_prelude::S;
-   |               ^^^^^^^^^^^^^^ maybe a missing `extern crate extern_prelude;`?
+   |               ^^^^^^^^^^^^^^ maybe a missing crate `extern_prelude`?
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/feature-gates/feature-gate-extern_absolute_paths.stderr b/src/test/ui/feature-gates/feature-gate-extern_absolute_paths.stderr
index 59b28704ddb..2f4c220ee95 100644
--- a/src/test/ui/feature-gates/feature-gate-extern_absolute_paths.stderr
+++ b/src/test/ui/feature-gates/feature-gate-extern_absolute_paths.stderr
@@ -2,13 +2,13 @@ error[E0432]: unresolved import `core`
   --> $DIR/feature-gate-extern_absolute_paths.rs:1:5
    |
 LL | use core::default;
-   |     ^^^^ maybe a missing `extern crate core;`?
+   |     ^^^^ maybe a missing crate `core`?
 
-error[E0433]: failed to resolve: maybe a missing `extern crate core;`?
+error[E0433]: failed to resolve: maybe a missing crate `core`?
   --> $DIR/feature-gate-extern_absolute_paths.rs:4:19
    |
 LL |     let _: u8 = ::core::default::Default();
-   |                   ^^^^ maybe a missing `extern crate core;`?
+   |                   ^^^^ maybe a missing crate `core`?
 
 error: aborting due to 2 previous errors
 
diff --git a/src/test/ui/import3.stderr b/src/test/ui/import3.stderr
index 73b9b27b57c..7bb413be59f 100644
--- a/src/test/ui/import3.stderr
+++ b/src/test/ui/import3.stderr
@@ -2,7 +2,7 @@ error[E0432]: unresolved import `main`
   --> $DIR/import3.rs:2:5
    |
 LL | use main::bar;
-   |     ^^^^ maybe a missing `extern crate main;`?
+   |     ^^^^ maybe a missing crate `main`?
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/imports/issue-53269.stderr b/src/test/ui/imports/issue-53269.stderr
index 613c59867c9..bbec2aae825 100644
--- a/src/test/ui/imports/issue-53269.stderr
+++ b/src/test/ui/imports/issue-53269.stderr
@@ -2,7 +2,7 @@ error[E0432]: unresolved import `nonexistent_module`
   --> $DIR/issue-53269.rs:6:9
    |
 LL |     use nonexistent_module::mac;
-   |         ^^^^^^^^^^^^^^^^^^ maybe a missing `extern crate nonexistent_module;`?
+   |         ^^^^^^^^^^^^^^^^^^ maybe a missing crate `nonexistent_module`?
 
 error[E0659]: `mac` is ambiguous (`macro_rules` vs non-`macro_rules` from other module)
   --> $DIR/issue-53269.rs:8:5
diff --git a/src/test/ui/imports/issue-55457.stderr b/src/test/ui/imports/issue-55457.stderr
index 86a76c1d89c..aa103ba01e3 100644
--- a/src/test/ui/imports/issue-55457.stderr
+++ b/src/test/ui/imports/issue-55457.stderr
@@ -11,7 +11,7 @@ error[E0432]: unresolved import `non_existent`
   --> $DIR/issue-55457.rs:2:5
    |
 LL | use non_existent::non_existent;
-   |     ^^^^^^^^^^^^ maybe a missing `extern crate non_existent;`?
+   |     ^^^^^^^^^^^^ maybe a missing crate `non_existent`?
 
 error: cannot determine resolution for the derive macro `NonExistent`
   --> $DIR/issue-55457.rs:5:10
diff --git a/src/test/ui/imports/unresolved-imports-used.stderr b/src/test/ui/imports/unresolved-imports-used.stderr
index f20db881c86..e8c827a6179 100644
--- a/src/test/ui/imports/unresolved-imports-used.stderr
+++ b/src/test/ui/imports/unresolved-imports-used.stderr
@@ -8,7 +8,7 @@ error[E0432]: unresolved import `foo`
   --> $DIR/unresolved-imports-used.rs:10:5
    |
 LL | use foo::bar;
-   |     ^^^ maybe a missing `extern crate foo;`?
+   |     ^^^ maybe a missing crate `foo`?
 
 error[E0603]: function `quz` is private
   --> $DIR/unresolved-imports-used.rs:8:10
diff --git a/src/test/ui/issues/issue-1697.rs b/src/test/ui/issues/issue-1697.rs
index 30b2558dce9..5cd76d21f91 100644
--- a/src/test/ui/issues/issue-1697.rs
+++ b/src/test/ui/issues/issue-1697.rs
@@ -1,6 +1,6 @@
 // Testing that we don't fail abnormally after hitting the errors
 
 use unresolved::*; //~ ERROR unresolved import `unresolved` [E0432]
-                   //~^ maybe a missing `extern crate unresolved;`?
+                   //~^ maybe a missing crate `unresolved`?
 
 fn main() {}
diff --git a/src/test/ui/issues/issue-1697.stderr b/src/test/ui/issues/issue-1697.stderr
index 6ae5bd1fc26..a76fd309914 100644
--- a/src/test/ui/issues/issue-1697.stderr
+++ b/src/test/ui/issues/issue-1697.stderr
@@ -2,7 +2,7 @@ error[E0432]: unresolved import `unresolved`
   --> $DIR/issue-1697.rs:3:5
    |
 LL | use unresolved::*;
-   |     ^^^^^^^^^^ maybe a missing `extern crate unresolved;`?
+   |     ^^^^^^^^^^ maybe a missing crate `unresolved`?
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-33464.stderr b/src/test/ui/issues/issue-33464.stderr
index bbf8d21cf65..d3bf404c99a 100644
--- a/src/test/ui/issues/issue-33464.stderr
+++ b/src/test/ui/issues/issue-33464.stderr
@@ -2,19 +2,19 @@ error[E0432]: unresolved import `abc`
   --> $DIR/issue-33464.rs:3:5
    |
 LL | use abc::one_el;
-   |     ^^^ maybe a missing `extern crate abc;`?
+   |     ^^^ maybe a missing crate `abc`?
 
 error[E0432]: unresolved import `abc`
   --> $DIR/issue-33464.rs:5:5
    |
 LL | use abc::{a, bbb, cccccc};
-   |     ^^^ maybe a missing `extern crate abc;`?
+   |     ^^^ maybe a missing crate `abc`?
 
 error[E0432]: unresolved import `a_very_long_name`
   --> $DIR/issue-33464.rs:7:5
    |
 LL | use a_very_long_name::{el, el2};
-   |     ^^^^^^^^^^^^^^^^ maybe a missing `extern crate a_very_long_name;`?
+   |     ^^^^^^^^^^^^^^^^ maybe a missing crate `a_very_long_name`?
 
 error: aborting due to 3 previous errors
 
diff --git a/src/test/ui/issues/issue-36881.stderr b/src/test/ui/issues/issue-36881.stderr
index 07d2c99d7d2..caf9d5d6d62 100644
--- a/src/test/ui/issues/issue-36881.stderr
+++ b/src/test/ui/issues/issue-36881.stderr
@@ -2,7 +2,7 @@ error[E0432]: unresolved import `issue_36881_aux`
   --> $DIR/issue-36881.rs:5:9
    |
 LL |     use issue_36881_aux::Foo;
-   |         ^^^^^^^^^^^^^^^ maybe a missing `extern crate issue_36881_aux;`?
+   |         ^^^^^^^^^^^^^^^ maybe a missing crate `issue_36881_aux`?
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/issues/issue-37887.stderr b/src/test/ui/issues/issue-37887.stderr
index b1b9754523f..6ef5359f980 100644
--- a/src/test/ui/issues/issue-37887.stderr
+++ b/src/test/ui/issues/issue-37887.stderr
@@ -2,7 +2,7 @@ error[E0432]: unresolved import `libc`
   --> $DIR/issue-37887.rs:3:9
    |
 LL |     use libc::*;
-   |         ^^^^ maybe a missing `extern crate libc;`?
+   |         ^^^^ maybe a missing crate `libc`?
 
 error[E0658]: use of unstable library feature 'rustc_private': this crate is being loaded from the sysroot, an unstable location; did you mean to load this crate from crates.io via `Cargo.toml` instead?
   --> $DIR/issue-37887.rs:2:5
diff --git a/src/test/ui/macros/meta-item-absolute-path.stderr b/src/test/ui/macros/meta-item-absolute-path.stderr
index 23933f730aa..711fa4dd405 100644
--- a/src/test/ui/macros/meta-item-absolute-path.stderr
+++ b/src/test/ui/macros/meta-item-absolute-path.stderr
@@ -1,8 +1,8 @@
-error[E0433]: failed to resolve: maybe a missing `extern crate Absolute;`?
+error[E0433]: failed to resolve: maybe a missing crate `Absolute`?
   --> $DIR/meta-item-absolute-path.rs:1:12
    |
 LL | #[derive(::Absolute)]
-   |            ^^^^^^^^ maybe a missing `extern crate Absolute;`?
+   |            ^^^^^^^^ maybe a missing crate `Absolute`?
 
 error: aborting due to previous error
 
diff --git a/src/test/ui/privacy/restricted/test.rs b/src/test/ui/privacy/restricted/test.rs
index f208696c86f..a8c269378c2 100644
--- a/src/test/ui/privacy/restricted/test.rs
+++ b/src/test/ui/privacy/restricted/test.rs
@@ -47,6 +47,6 @@ fn main() {
 }
 
 mod pathological {
-    pub(in bad::path) mod m1 {} //~ ERROR failed to resolve: maybe a missing `extern crate bad;`?
+    pub(in bad::path) mod m1 {} //~ ERROR failed to resolve: maybe a missing crate `bad`?
     pub(in foo) mod m2 {} //~ ERROR visibilities can only be restricted to ancestor modules
 }
diff --git a/src/test/ui/privacy/restricted/test.stderr b/src/test/ui/privacy/restricted/test.stderr
index fa78ae759c7..a23973d0853 100644
--- a/src/test/ui/privacy/restricted/test.stderr
+++ b/src/test/ui/privacy/restricted/test.stderr
@@ -1,8 +1,8 @@
-error[E0433]: failed to resolve: maybe a missing `extern crate bad;`?
+error[E0433]: failed to resolve: maybe a missing crate `bad`?
   --> $DIR/test.rs:50:12
    |
 LL |     pub(in bad::path) mod m1 {}
-   |            ^^^ maybe a missing `extern crate bad;`?
+   |            ^^^ maybe a missing crate `bad`?
 
 error: visibilities can only be restricted to ancestor modules
   --> $DIR/test.rs:51:12
diff --git a/src/test/ui/unresolved/unresolved-import.rs b/src/test/ui/unresolved/unresolved-import.rs
index 4c7d4bb9353..b65c3dfb90b 100644
--- a/src/test/ui/unresolved/unresolved-import.rs
+++ b/src/test/ui/unresolved/unresolved-import.rs
@@ -1,5 +1,5 @@
 use foo::bar; //~ ERROR unresolved import `foo` [E0432]
-              //~^ maybe a missing `extern crate foo;`?
+              //~^ maybe a missing crate `foo`?
 
 use bar::Baz as x; //~ ERROR unresolved import `bar::Baz` [E0432]
                    //~| no `Baz` in `bar`
diff --git a/src/test/ui/unresolved/unresolved-import.stderr b/src/test/ui/unresolved/unresolved-import.stderr
index fb5c0760d15..d4bfea57809 100644
--- a/src/test/ui/unresolved/unresolved-import.stderr
+++ b/src/test/ui/unresolved/unresolved-import.stderr
@@ -2,7 +2,7 @@ error[E0432]: unresolved import `foo`
   --> $DIR/unresolved-import.rs:1:5
    |
 LL | use foo::bar;
-   |     ^^^ maybe a missing `extern crate foo;`?
+   |     ^^^ maybe a missing crate `foo`?
 
 error[E0432]: unresolved import `bar::Baz`
   --> $DIR/unresolved-import.rs:4:5
diff --git a/src/test/ui/use/use-mod/use-mod-4.stderr b/src/test/ui/use/use-mod/use-mod-4.stderr
index df9898844d3..e30e5c3ceb1 100644
--- a/src/test/ui/use/use-mod/use-mod-4.stderr
+++ b/src/test/ui/use/use-mod/use-mod-4.stderr
@@ -14,7 +14,7 @@ error[E0432]: unresolved import `foo`
   --> $DIR/use-mod-4.rs:1:5
    |
 LL | use foo::self;
-   |     ^^^ maybe a missing `extern crate foo;`?
+   |     ^^^ maybe a missing crate `foo`?
 
 error: aborting due to 3 previous errors
 
diff --git a/src/tools/miri b/src/tools/miri
-Subproject 39a524f694e42cfb178639d490d3fdbbaf8569d
+Subproject b12ebfc3de853abf6b4260c44a71cd51323803c