Merge ref '8e3710ef31a0' from rust-lang/rust

Pull recent changes from https://github.com/rust-lang/rust via Josh.

Upstream ref: 8e3710ef31a0b2cdf5a1c2f3929b7735d1e28c20
Filtered ref: 3629e47f19f1c1c9710f45b80a31eb32d851baf6

This merge was created using https://github.com/rust-lang/josh-sync.

42 files changed, 162 insertions, 287 deletions

diff --git a/src/bootstrap/src/core/build_steps/gcc.rs b/src/bootstrap/src/core/build_steps/gcc.rs
index 2b36b0f2e27..77c9622a9bf 100644
--- a/src/bootstrap/src/core/build_steps/gcc.rs
+++ b/src/bootstrap/src/core/build_steps/gcc.rs
@@ -122,7 +122,7 @@ fn try_download_gcc(builder: &Builder<'_>, target: TargetSelection) -> Option<Pa
     match source {
         PathFreshness::LastModifiedUpstream { upstream } => {
             // Download from upstream CI
-            let root = ci_gcc_root(&builder.config);
+            let root = ci_gcc_root(&builder.config, target);
             let gcc_stamp = BuildStamp::new(&root).with_prefix("gcc").add_stamp(&upstream);
             if !gcc_stamp.is_up_to_date() && !builder.config.dry_run() {
                 builder.config.download_ci_gcc(&upstream, &root);
@@ -286,8 +286,8 @@ pub fn add_cg_gcc_cargo_flags(cargo: &mut Cargo, gcc: &GccOutput) {
 
 /// The absolute path to the downloaded GCC artifacts.
 #[cfg(not(test))]
-fn ci_gcc_root(config: &crate::Config) -> PathBuf {
-    config.out.join(config.host_target).join("ci-gcc")
+fn ci_gcc_root(config: &crate::Config, target: TargetSelection) -> PathBuf {
+    config.out.join(target).join("ci-gcc")
 }
 
 /// Detect whether GCC sources have been modified locally or not.
diff --git a/src/bootstrap/src/core/build_steps/llvm.rs b/src/bootstrap/src/core/build_steps/llvm.rs
index 260108292e0..024cac2f2fe 100644
--- a/src/bootstrap/src/core/build_steps/llvm.rs
+++ b/src/bootstrap/src/core/build_steps/llvm.rs
@@ -220,10 +220,6 @@ pub(crate) fn is_ci_llvm_available_for_target(
         ("armv7-unknown-linux-gnueabihf", false),
         ("loongarch64-unknown-linux-gnu", false),
         ("loongarch64-unknown-linux-musl", false),
-        ("mips-unknown-linux-gnu", false),
-        ("mips64-unknown-linux-gnuabi64", false),
-        ("mips64el-unknown-linux-gnuabi64", false),
-        ("mipsel-unknown-linux-gnu", false),
         ("powerpc-unknown-linux-gnu", false),
         ("powerpc64-unknown-linux-gnu", false),
         ("powerpc64le-unknown-linux-gnu", false),
diff --git a/src/bootstrap/src/core/build_steps/test.rs b/src/bootstrap/src/core/build_steps/test.rs
index e7a57a7f375..56e7582a6ff 100644
--- a/src/bootstrap/src/core/build_steps/test.rs
+++ b/src/bootstrap/src/core/build_steps/test.rs
@@ -1830,10 +1830,27 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
         cmd.arg("--host").arg(&*compiler.host.triple);
         cmd.arg("--llvm-filecheck").arg(builder.llvm_filecheck(builder.config.host_target));
 
-        if let Some(codegen_backend) = builder.config.default_codegen_backend(compiler.host) {
-            // Tells compiletest which codegen backend is used by default by the compiler.
+        if let Some(codegen_backend) = builder.config.cmd.test_codegen_backend() {
+            if !builder.config.enabled_codegen_backends(compiler.host).contains(codegen_backend) {
+                eprintln!(
+                    "\
+ERROR: No configured backend named `{name}`
+HELP: You can add it into `bootstrap.toml` in `rust.codegen-backends = [{name:?}]`",
+                    name = codegen_backend.name(),
+                );
+                crate::exit!(1);
+            }
+            // Tells compiletest that we want to use this codegen in particular and to override
+            // the default one.
+            cmd.arg("--override-codegen-backend").arg(codegen_backend.name());
+            // Tells compiletest which codegen backend to use.
+            // It is used to e.g. ignore tests that don't support that codegen backend.
+            cmd.arg("--default-codegen-backend").arg(codegen_backend.name());
+        } else {
+            // Tells compiletest which codegen backend to use.
             // It is used to e.g. ignore tests that don't support that codegen backend.
-            cmd.arg("--codegen-backend").arg(codegen_backend.name());
+            cmd.arg("--default-codegen-backend")
+                .arg(builder.config.default_codegen_backend(compiler.host).unwrap().name());
         }
 
         if builder.build.config.llvm_enzyme {
diff --git a/src/bootstrap/src/core/builder/cargo.rs b/src/bootstrap/src/core/builder/cargo.rs
index 69a744a86cb..72192403412 100644
--- a/src/bootstrap/src/core/builder/cargo.rs
+++ b/src/bootstrap/src/core/builder/cargo.rs
@@ -1326,7 +1326,12 @@ impl Builder<'_> {
 
             if let Some(limit) = limit
                 && (build_compiler_stage == 0
-                    || self.config.default_codegen_backend(target).unwrap_or_default().is_llvm())
+                    || self
+                        .config
+                        .default_codegen_backend(target)
+                        .cloned()
+                        .unwrap_or_default()
+                        .is_llvm())
             {
                 rustflags.arg(&format!("-Cllvm-args=-import-instr-limit={limit}"));
             }
diff --git a/src/bootstrap/src/core/builder/tests.rs b/src/bootstrap/src/core/builder/tests.rs
index a7db96055e6..a2fe546c60a 100644
--- a/src/bootstrap/src/core/builder/tests.rs
+++ b/src/bootstrap/src/core/builder/tests.rs
@@ -1591,7 +1591,7 @@ mod snapshot {
         insta::assert_snapshot!(
             ctx.config("check")
                 .path("compiler")
-                .render_steps(), @"[check] rustc 0 <host> -> rustc 1 <host> (73 crates)");
+                .render_steps(), @"[check] rustc 0 <host> -> rustc 1 <host> (74 crates)");
     }
 
     #[test]
@@ -1617,7 +1617,7 @@ mod snapshot {
             ctx.config("check")
                 .path("compiler")
                 .stage(1)
-                .render_steps(), @"[check] rustc 0 <host> -> rustc 1 <host> (73 crates)");
+                .render_steps(), @"[check] rustc 0 <host> -> rustc 1 <host> (74 crates)");
     }
 
     #[test]
@@ -1631,7 +1631,7 @@ mod snapshot {
         [build] llvm <host>
         [build] rustc 0 <host> -> rustc 1 <host>
         [build] rustc 1 <host> -> std 1 <host>
-        [check] rustc 1 <host> -> rustc 2 <host> (73 crates)
+        [check] rustc 1 <host> -> rustc 2 <host> (74 crates)
         ");
     }
 
@@ -1647,7 +1647,7 @@ mod snapshot {
         [build] rustc 0 <host> -> rustc 1 <host>
         [build] rustc 1 <host> -> std 1 <host>
         [check] rustc 1 <host> -> std 1 <target1>
-        [check] rustc 1 <host> -> rustc 2 <target1> (73 crates)
+        [check] rustc 1 <host> -> rustc 2 <target1> (74 crates)
         [check] rustc 1 <host> -> rustc 2 <target1>
         [check] rustc 1 <host> -> Rustdoc 2 <target1>
         [check] rustc 1 <host> -> rustc_codegen_cranelift 2 <target1>
@@ -1743,7 +1743,7 @@ mod snapshot {
             ctx.config("check")
                 .paths(&["library", "compiler"])
                 .args(&args)
-                .render_steps(), @"[check] rustc 0 <host> -> rustc 1 <host> (73 crates)");
+                .render_steps(), @"[check] rustc 0 <host> -> rustc 1 <host> (74 crates)");
     }
 
     #[test]
diff --git a/src/bootstrap/src/core/config/config.rs b/src/bootstrap/src/core/config/config.rs
index 5eea5436023..d0647537e56 100644
--- a/src/bootstrap/src/core/config/config.rs
+++ b/src/bootstrap/src/core/config/config.rs
@@ -1755,8 +1755,8 @@ impl Config {
 
     /// Returns the codegen backend that should be configured as the *default* codegen backend
     /// for a rustc compiled by bootstrap.
-    pub fn default_codegen_backend(&self, target: TargetSelection) -> Option<CodegenBackendKind> {
-        self.enabled_codegen_backends(target).first().cloned()
+    pub fn default_codegen_backend(&self, target: TargetSelection) -> Option<&CodegenBackendKind> {
+        self.enabled_codegen_backends(target).first()
     }
 
     pub fn jemalloc(&self, target: TargetSelection) -> bool {
diff --git a/src/bootstrap/src/core/config/flags.rs b/src/bootstrap/src/core/config/flags.rs
index 17bfb388280..c01b71b9260 100644
--- a/src/bootstrap/src/core/config/flags.rs
+++ b/src/bootstrap/src/core/config/flags.rs
@@ -15,7 +15,7 @@ use crate::core::build_steps::setup::Profile;
 use crate::core::builder::{Builder, Kind};
 use crate::core::config::Config;
 use crate::core::config::target_selection::{TargetSelectionList, target_selection_list};
-use crate::{Build, DocTests};
+use crate::{Build, CodegenBackendKind, DocTests};
 
 #[derive(Copy, Clone, Default, Debug, ValueEnum)]
 pub enum Color {
@@ -419,6 +419,9 @@ pub enum Subcommand {
         #[arg(long)]
         /// don't capture stdout/stderr of tests
         no_capture: bool,
+        #[arg(long)]
+        /// Use a different codegen backend when running tests.
+        test_codegen_backend: Option<CodegenBackendKind>,
     },
     /// Build and run some test suites *in Miri*
     Miri {
@@ -658,6 +661,13 @@ impl Subcommand {
             _ => vec![],
         }
     }
+
+    pub fn test_codegen_backend(&self) -> Option<&CodegenBackendKind> {
+        match self {
+            Subcommand::Test { test_codegen_backend, .. } => test_codegen_backend.as_ref(),
+            _ => None,
+        }
+    }
 }
 
 /// Returns the shell completion for a given shell, if the result differs from the current
diff --git a/src/bootstrap/src/lib.rs b/src/bootstrap/src/lib.rs
index 8f766ed00a5..ec7edbf7531 100644
--- a/src/bootstrap/src/lib.rs
+++ b/src/bootstrap/src/lib.rs
@@ -165,6 +165,20 @@ impl CodegenBackendKind {
     }
 }
 
+impl std::str::FromStr for CodegenBackendKind {
+    type Err = &'static str;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        match s.to_lowercase().as_str() {
+            "" => Err("Invalid empty backend name"),
+            "gcc" => Ok(Self::Gcc),
+            "llvm" => Ok(Self::Llvm),
+            "cranelift" => Ok(Self::Cranelift),
+            _ => Ok(Self::Custom(s.to_string())),
+        }
+    }
+}
+
 #[derive(PartialEq, Eq, Copy, Clone, Debug)]
 pub enum DocTests {
     /// Run normal tests and doc tests (default).
diff --git a/src/bootstrap/src/utils/change_tracker.rs b/src/bootstrap/src/utils/change_tracker.rs
index b2f9960a449..4fb5891ed18 100644
--- a/src/bootstrap/src/utils/change_tracker.rs
+++ b/src/bootstrap/src/utils/change_tracker.rs
@@ -507,6 +507,11 @@ pub const CONFIG_CHANGE_HISTORY: &[ChangeInfo] = &[
         summary: "It is no longer possible to `x clippy` with stage 0. All clippy commands have to be on stage 1+.",
     },
     ChangeInfo {
+        change_id: 145256,
+        severity: ChangeSeverity::Info,
+        summary: "Added `--test-codegen-backend` CLI option for tests",
+    },
+    ChangeInfo {
         change_id: 145379,
         severity: ChangeSeverity::Info,
         summary: "Build/check now supports forwarding `--timings` flag to cargo.",
diff --git a/src/ci/github-actions/jobs.yml b/src/ci/github-actions/jobs.yml
index 8cfcc0c5b15..409d2cba821 100644
--- a/src/ci/github-actions/jobs.yml
+++ b/src/ci/github-actions/jobs.yml
@@ -28,7 +28,6 @@ runners:
 
   - &job-windows
     os: windows-2025
-    free_disk: true
     <<: *base-job
 
   - &job-windows-8c
diff --git a/src/ci/scripts/free-disk-space-windows-start.py b/src/ci/scripts/free-disk-space-windows-start.py
deleted file mode 100644
index fbaad722bff..00000000000
--- a/src/ci/scripts/free-disk-space-windows-start.py
+++ /dev/null
@@ -1,72 +0,0 @@
-"""
-Start freeing disk space on Windows in the background by launching
-the PowerShell cleanup script, and recording the PID in a file,
-so later steps can wait for completion.
-"""
-
-import subprocess
-from pathlib import Path
-from free_disk_space_windows_util import get_pid_file, get_log_file, run_main
-
-
-def get_cleanup_script() -> Path:
-    script_dir = Path(__file__).resolve().parent
-    cleanup_script = script_dir / "free-disk-space-windows.ps1"
-    if not cleanup_script.exists():
-        raise Exception(f"Cleanup script '{cleanup_script}' not found")
-    return cleanup_script
-
-
-def write_pid(pid: int):
-    pid_file = get_pid_file()
-    if pid_file.exists():
-        raise Exception(f"Pid file '{pid_file}' already exists")
-    pid_file.write_text(str(pid))
-    print(f"wrote pid {pid} in file {pid_file}")
-
-
-def launch_cleanup_process():
-    cleanup_script = get_cleanup_script()
-    log_file_path = get_log_file()
-    # Launch the PowerShell cleanup in the background and redirect logs.
-    try:
-        with open(log_file_path, "w", encoding="utf-8") as log_file:
-            proc = subprocess.Popen(
-                [
-                    "pwsh",
-                    # Suppress PowerShell startup banner/logo for cleaner logs.
-                    "-NoLogo",
-                    # Don't load user/system profiles. Ensures a clean, predictable environment.
-                    "-NoProfile",
-                    # Disable interactive prompts. Required for CI to avoid hangs.
-                    "-NonInteractive",
-                    # Execute the specified script file (next argument).
-                    "-File",
-                    str(cleanup_script),
-                ],
-                # Write child stdout to the log file.
-                stdout=log_file,
-                # Merge stderr into stdout for a single, ordered log stream.
-                stderr=subprocess.STDOUT,
-            )
-            print(
-                f"Started free-disk-space cleanup in background. "
-                f"pid={proc.pid}; log_file={log_file_path}"
-            )
-            return proc
-    except FileNotFoundError as e:
-        raise Exception("pwsh not found on PATH; cannot start disk cleanup.") from e
-
-
-def main() -> int:
-    proc = launch_cleanup_process()
-
-    # Write pid of the process to a file, so that later steps can read it and wait
-    # until the process completes.
-    write_pid(proc.pid)
-
-    return 0
-
-
-if __name__ == "__main__":
-    run_main(main)
diff --git a/src/ci/scripts/free-disk-space-windows-wait.py b/src/ci/scripts/free-disk-space-windows-wait.py
deleted file mode 100644
index d510781d534..00000000000
--- a/src/ci/scripts/free-disk-space-windows-wait.py
+++ /dev/null
@@ -1,92 +0,0 @@
-"""
-Wait for the background Windows disk cleanup process.
-"""
-
-import ctypes
-import time
-from free_disk_space_windows_util import get_pid_file, get_log_file, run_main
-
-
-def is_process_running(pid: int) -> bool:
-    PROCESS_QUERY_LIMITED_INFORMATION = 0x1000
-    processHandle = ctypes.windll.kernel32.OpenProcess(
-        PROCESS_QUERY_LIMITED_INFORMATION, 0, pid
-    )
-    if processHandle == 0:
-        # The process is not running.
-        # If you don't have the sufficient rights to check if a process is running,
-        # zero is also returned. But in GitHub Actions we have these rights.
-        return False
-    else:
-        ctypes.windll.kernel32.CloseHandle(processHandle)
-        return True
-
-
-def print_logs():
-    """Print the logs from the cleanup script."""
-    log_file = get_log_file()
-    if log_file.exists():
-        print("free-disk-space logs:")
-        # Print entire log; replace undecodable bytes to avoid exceptions.
-        try:
-            with open(log_file, "r", encoding="utf-8", errors="replace") as f:
-                print(f.read())
-        except Exception as e:
-            raise Exception(f"Failed to read log file '{log_file}'") from e
-    else:
-        print(f"::warning::Log file '{log_file}' not found")
-
-
-def read_pid_from_file() -> int:
-    """Read the PID from the pid file."""
-
-    pid_file = get_pid_file()
-    if not pid_file.exists():
-        raise Exception(
-            f"No background free-disk-space process to wait for: pid file {pid_file} not found"
-        )
-
-    pid_file_content = pid_file.read_text().strip()
-
-    # Delete the file if it exists
-    pid_file.unlink(missing_ok=True)
-
-    try:
-        # Read the first line and convert to int.
-        pid = int(pid_file_content.splitlines()[0])
-        return pid
-    except Exception as e:
-        raise Exception(
-            f"Error while parsing the pid file with content '{pid_file_content!r}'"
-        ) from e
-
-
-def wait_for_process(pid: int):
-    timeout_duration_seconds = 5 * 60
-    interval_seconds = 3
-    max_attempts = timeout_duration_seconds / interval_seconds
-    attempts = 0
-
-    # Poll until process exits
-    while is_process_running(pid):
-        if attempts >= max_attempts:
-            print(
-                "::warning::Timeout expired while waiting for the disk cleanup process to finish."
-            )
-            break
-        time.sleep(interval_seconds)
-        attempts += 1
-
-
-def main() -> int:
-    pid = read_pid_from_file()
-
-    wait_for_process(pid)
-
-    print_logs()
-
-    return 0
-
-
-if __name__ == "__main__":
-    run_main(main)
diff --git a/src/ci/scripts/free-disk-space-windows.ps1 b/src/ci/scripts/free-disk-space-windows.ps1
deleted file mode 100644
index 8a4677bd2ab..00000000000
--- a/src/ci/scripts/free-disk-space-windows.ps1
+++ /dev/null
@@ -1,35 +0,0 @@
-# Free disk space on Windows GitHub action runners.
-
-$ErrorActionPreference = 'Stop'
-
-Get-Volume | Out-String | Write-Output
-
-$available = $(Get-Volume C).SizeRemaining
-
-$dirs = 'C:\Program Files\Microsoft Visual Studio\2022\Enterprise\VC\Tools\Llvm',
-'C:\rtools45', 'C:\ghcup', 'C:\Program Files (x86)\Android',
-'C:\Program Files\Google\Chrome', 'C:\Program Files (x86)\Microsoft\Edge',
-'C:\Program Files\Mozilla Firefox', 'C:\Program Files\MySQL', 'C:\Julia',
-'C:\Program Files\MongoDB', 'C:\Program Files\Azure Cosmos DB Emulator',
-'C:\Program Files\PostgreSQL', 'C:\Program Files\Unity Hub',
-'C:\Strawberry', 'C:\hostedtoolcache\windows\Java_Temurin-Hotspot_jdk'
-
-foreach ($dir in $dirs) {
-    Start-ThreadJob -InputObject $dir {
-        Remove-Item -Recurse -Force -LiteralPath $input
-    } | Out-Null
-}
-
-foreach ($job in Get-Job) {
-    Wait-Job $job  | Out-Null
-    if ($job.Error) {
-        Write-Output "::warning file=$PSCommandPath::$($job.Error)"
-    }
-    Remove-Job $job
-}
-
-Get-Volume | Out-String | Write-Output
-
-$saved = ($(Get-Volume C).SizeRemaining - $available) / 1gb
-$savedRounded = [math]::Round($saved, 3)
-Write-Output "total space saved: $savedRounded GB"
diff --git a/src/ci/scripts/free-disk-space.sh b/src/ci/scripts/free-disk-space.sh
deleted file mode 100755
index 9264fe4de6d..00000000000
--- a/src/ci/scripts/free-disk-space.sh
+++ /dev/null
@@ -1,10 +0,0 @@
-#!/bin/bash
-set -euo pipefail
-
-script_dir=$(dirname "$0")
-
-if [[ "${RUNNER_OS:-}" == "Windows" ]]; then
-    python3 "$script_dir/free-disk-space-windows-start.py"
-else
-    $script_dir/free-disk-space-linux.sh
-fi
diff --git a/src/ci/scripts/free_disk_space_windows_util.py b/src/ci/scripts/free_disk_space_windows_util.py
deleted file mode 100644
index 488187864c2..00000000000
--- a/src/ci/scripts/free_disk_space_windows_util.py
+++ /dev/null
@@ -1,29 +0,0 @@
-"""
-Utilities for Windows disk space cleanup scripts.
-"""
-
-import os
-from pathlib import Path
-import sys
-
-
-def get_temp_dir() -> Path:
-    """Get the temporary directory set by GitHub Actions."""
-    return Path(os.environ.get("RUNNER_TEMP"))
-
-
-def get_pid_file() -> Path:
-    return get_temp_dir() / "free-disk-space.pid"
-
-
-def get_log_file() -> Path:
-    return get_temp_dir() / "free-disk-space.log"
-
-
-def run_main(main_fn):
-    exit_code = 1
-    try:
-        exit_code = main_fn()
-    except Exception as e:
-        print(f"::error::{e}")
-    sys.exit(exit_code)
diff --git a/src/doc/rustc-dev-guide/src/autodiff/internals.md b/src/doc/rustc-dev-guide/src/autodiff/internals.md
index c1b31a0e4bd..c8e304f814b 100644
--- a/src/doc/rustc-dev-guide/src/autodiff/internals.md
+++ b/src/doc/rustc-dev-guide/src/autodiff/internals.md
@@ -17,7 +17,7 @@ fn main() {
 
 The detailed documentation for the `std::autodiff` module is available at [std::autodiff](https://doc.rust-lang.org/std/autodiff/index.html).
 
-Differentiable programing is used in various fields like numerical computing, [solid mechanics][ratel], [computational chemistry][molpipx], [fluid dynamics][waterlily] or for Neural Network training via Backpropagation, [ODE solver][diffsol], [differentiable rendering][libigl], [quantum computing][catalyst], and climate simulations.
+Differentiable programming is used in various fields like numerical computing, [solid mechanics][ratel], [computational chemistry][molpipx], [fluid dynamics][waterlily] or for Neural Network training via Backpropagation, [ODE solver][diffsol], [differentiable rendering][libigl], [quantum computing][catalyst], and climate simulations.
 
 [ratel]: https://gitlab.com/micromorph/ratel
 [molpipx]: https://arxiv.org/abs/2411.17011v
diff --git a/src/doc/rustc-dev-guide/src/solve/candidate-preference.md b/src/doc/rustc-dev-guide/src/solve/candidate-preference.md
index 89605294735..8b28f56760a 100644
--- a/src/doc/rustc-dev-guide/src/solve/candidate-preference.md
+++ b/src/doc/rustc-dev-guide/src/solve/candidate-preference.md
@@ -95,7 +95,7 @@ fn overflow<T: Trait>() {
 ```
 
 This preference causes a lot of issues. See [#24066]. Most of the
-issues are caused by prefering where-bounds over impls even if the where-bound guides type inference:
+issues are caused by preferring where-bounds over impls even if the where-bound guides type inference:
 ```rust
 trait Trait<T> {
     fn call_me(&self, x: T) {}
diff --git a/src/doc/rustc/src/platform-support/wasm32-wali-linux.md b/src/doc/rustc/src/platform-support/wasm32-wali-linux.md
index 3213e2b0c8f..001159b0d32 100644
--- a/src/doc/rustc/src/platform-support/wasm32-wali-linux.md
+++ b/src/doc/rustc/src/platform-support/wasm32-wali-linux.md
@@ -31,7 +31,7 @@ This target is cross-compiled and requires an installation of the [WALI compiler
 > **Note**: Users can expect that new enabled-by-default Wasm features for LLVM are transitively incorporatable into this target -- see [wasm32-unknown-unknown](wasm32-unknown-unknown.md) for detailed information on WebAssembly features.
 
 
-> **Note**: The WALI ABI is similar to default Clang wasm32 ABIs but *not identical*. The primary difference is 64-bit `long` types as opposed to 32-bit for wasm32. This is required to mantain minimum source code changes for 64-bit host platforms currently supported. This may change in the future as the spec evolves.
+> **Note**: The WALI ABI is similar to default Clang wasm32 ABIs but *not identical*. The primary difference is 64-bit `long` types as opposed to 32-bit for wasm32. This is required to maintain minimum source code changes for 64-bit host platforms currently supported. This may change in the future as the spec evolves.
 
 ### Execution
 Running generated WALI binaries also requires a supported compliant engine implementation -- a working implementation in the [WebAssembly Micro-Runtime (WAMR)](https://github.com/arjunr2/WALI) is included in the repo.
diff --git a/src/doc/unstable-book/src/compiler-flags/randomize-layout.md b/src/doc/unstable-book/src/compiler-flags/randomize-layout.md
index 84c6712bc23..81da0503d7f 100644
--- a/src/doc/unstable-book/src/compiler-flags/randomize-layout.md
+++ b/src/doc/unstable-book/src/compiler-flags/randomize-layout.md
@@ -7,7 +7,7 @@ The tracking issue for this feature is: [#106764](https://github.com/rust-lang/r
 The `-Zrandomize-layout` flag changes the layout algorithm for `repr(Rust)` types defined in the current crate from its normal
 optimization goals to pseudorandomly rearranging fields within the degrees of freedom provided by the largely unspecified
 default representation. This also affects type sizes and padding.
-Downstream intantiations of generic types defined in a crate with randomization enabled will also be randomized.
+Downstream instantiations of generic types defined in a crate with randomization enabled will also be randomized.
 
 It can be used to find unsafe code that accidentally relies on unspecified behavior.
 
diff --git a/src/etc/completions/x.fish b/src/etc/completions/x.fish
index 0b9af334214..544f9b97237 100644
--- a/src/etc/completions/x.fish
+++ b/src/etc/completions/x.fish
@@ -305,6 +305,7 @@ complete -c x -n "__fish_x_using_subcommand test" -l extra-checks -d 'comma-sepa
 complete -c x -n "__fish_x_using_subcommand test" -l compare-mode -d 'mode describing what file the actual ui output will be compared to' -r
 complete -c x -n "__fish_x_using_subcommand test" -l pass -d 'force {check,build,run}-pass tests to this mode' -r
 complete -c x -n "__fish_x_using_subcommand test" -l run -d 'whether to execute run-* tests' -r
+complete -c x -n "__fish_x_using_subcommand test" -l test-codegen-backend -d 'Use a different codegen backend when running tests' -r
 complete -c x -n "__fish_x_using_subcommand test" -l config -d 'TOML configuration file for build' -r -F
 complete -c x -n "__fish_x_using_subcommand test" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
 complete -c x -n "__fish_x_using_subcommand test" -l build -d 'host target of the stage0 compiler' -r -f
diff --git a/src/etc/completions/x.ps1 b/src/etc/completions/x.ps1
index 95cee4b6336..b03acf930f7 100644
--- a/src/etc/completions/x.ps1
+++ b/src/etc/completions/x.ps1
@@ -351,6 +351,7 @@ Register-ArgumentCompleter -Native -CommandName 'x' -ScriptBlock {
             [CompletionResult]::new('--compare-mode', '--compare-mode', [CompletionResultType]::ParameterName, 'mode describing what file the actual ui output will be compared to')
             [CompletionResult]::new('--pass', '--pass', [CompletionResultType]::ParameterName, 'force {check,build,run}-pass tests to this mode')
             [CompletionResult]::new('--run', '--run', [CompletionResultType]::ParameterName, 'whether to execute run-* tests')
+            [CompletionResult]::new('--test-codegen-backend', '--test-codegen-backend', [CompletionResultType]::ParameterName, 'Use a different codegen backend when running tests')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
             [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
diff --git a/src/etc/completions/x.py.fish b/src/etc/completions/x.py.fish
index 6fba6a45623..08e4cd26ce8 100644
--- a/src/etc/completions/x.py.fish
+++ b/src/etc/completions/x.py.fish
@@ -305,6 +305,7 @@ complete -c x.py -n "__fish_x.py_using_subcommand test" -l extra-checks -d 'comm
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l compare-mode -d 'mode describing what file the actual ui output will be compared to' -r
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l pass -d 'force {check,build,run}-pass tests to this mode' -r
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l run -d 'whether to execute run-* tests' -r
+complete -c x.py -n "__fish_x.py_using_subcommand test" -l test-codegen-backend -d 'Use a different codegen backend when running tests' -r
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l config -d 'TOML configuration file for build' -r -F
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l build-dir -d 'Build directory, overrides `build.build-dir` in `bootstrap.toml`' -r -f -a "(__fish_complete_directories)"
 complete -c x.py -n "__fish_x.py_using_subcommand test" -l build -d 'host target of the stage0 compiler' -r -f
diff --git a/src/etc/completions/x.py.ps1 b/src/etc/completions/x.py.ps1
index 458879a17a7..3d95d88af49 100644
--- a/src/etc/completions/x.py.ps1
+++ b/src/etc/completions/x.py.ps1
@@ -351,6 +351,7 @@ Register-ArgumentCompleter -Native -CommandName 'x.py' -ScriptBlock {
             [CompletionResult]::new('--compare-mode', '--compare-mode', [CompletionResultType]::ParameterName, 'mode describing what file the actual ui output will be compared to')
             [CompletionResult]::new('--pass', '--pass', [CompletionResultType]::ParameterName, 'force {check,build,run}-pass tests to this mode')
             [CompletionResult]::new('--run', '--run', [CompletionResultType]::ParameterName, 'whether to execute run-* tests')
+            [CompletionResult]::new('--test-codegen-backend', '--test-codegen-backend', [CompletionResultType]::ParameterName, 'Use a different codegen backend when running tests')
             [CompletionResult]::new('--config', '--config', [CompletionResultType]::ParameterName, 'TOML configuration file for build')
             [CompletionResult]::new('--build-dir', '--build-dir', [CompletionResultType]::ParameterName, 'Build directory, overrides `build.build-dir` in `bootstrap.toml`')
             [CompletionResult]::new('--build', '--build', [CompletionResultType]::ParameterName, 'host target of the stage0 compiler')
diff --git a/src/etc/completions/x.py.sh b/src/etc/completions/x.py.sh
index e003bf7fd0b..8ff0eaf35c8 100644
--- a/src/etc/completions/x.py.sh
+++ b/src/etc/completions/x.py.sh
@@ -3875,7 +3875,7 @@ _x.py() {
             return 0
             ;;
         x.py__test)
-            opts="-v -i -j -h --no-fail-fast --test-args --compiletest-rustc-args --no-doc --doc --bless --extra-checks --force-rerun --only-modified --compare-mode --pass --run --rustfix-coverage --no-capture --verbose --incremental --config --build-dir --build --host --target --exclude --skip --include-default-paths --rustc-error-format --on-fail --dry-run --dump-bootstrap-shims --stage --keep-stage --keep-stage-std --src --jobs --warnings --json-output --compile-time-deps --color --bypass-bootstrap-lock --rust-profile-generate --rust-profile-use --llvm-profile-use --llvm-profile-generate --enable-bolt-settings --skip-stage0-validation --reproducible-artifact --set --ci --skip-std-check-if-no-download-rustc --help [PATHS]... [ARGS]..."
+            opts="-v -i -j -h --no-fail-fast --test-args --compiletest-rustc-args --no-doc --doc --bless --extra-checks --force-rerun --only-modified --compare-mode --pass --run --rustfix-coverage --no-capture --test-codegen-backend --verbose --incremental --config --build-dir --build --host --target --exclude --skip --include-default-paths --rustc-error-format --on-fail --dry-run --dump-bootstrap-shims --stage --keep-stage --keep-stage-std --src --jobs --warnings --json-output --compile-time-deps --color --bypass-bootstrap-lock --rust-profile-generate --rust-profile-use --llvm-profile-use --llvm-profile-generate --enable-bolt-settings --skip-stage0-validation --reproducible-artifact --set --ci --skip-std-check-if-no-download-rustc --help [PATHS]... [ARGS]..."
             if [[ ${cur} == -* || ${COMP_CWORD} -eq 2 ]] ; then
                 COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                 return 0
@@ -3905,6 +3905,10 @@ _x.py() {
                     COMPREPLY=($(compgen -f "${cur}"))
                     return 0
                     ;;
+                --test-codegen-backend)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
                 --config)
                     local oldifs
                     if [ -n "${IFS+x}" ]; then
diff --git a/src/etc/completions/x.py.zsh b/src/etc/completions/x.py.zsh
index b82c2d65e86..9d2d73e582e 100644
--- a/src/etc/completions/x.py.zsh
+++ b/src/etc/completions/x.py.zsh
@@ -351,6 +351,7 @@ _arguments "${_arguments_options[@]}" : \
 '--compare-mode=[mode describing what file the actual ui output will be compared to]:COMPARE MODE:_default' \
 '--pass=[force {check,build,run}-pass tests to this mode]:check | build | run:_default' \
 '--run=[whether to execute run-* tests]:auto | always | never:_default' \
+'--test-codegen-backend=[Use a different codegen backend when running tests]:TEST_CODEGEN_BACKEND:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
 '--build=[host target of the stage0 compiler]:BUILD:' \
diff --git a/src/etc/completions/x.sh b/src/etc/completions/x.sh
index c2cb7710020..c1b73fb7c9e 100644
--- a/src/etc/completions/x.sh
+++ b/src/etc/completions/x.sh
@@ -3875,7 +3875,7 @@ _x() {
             return 0
             ;;
         x__test)
-            opts="-v -i -j -h --no-fail-fast --test-args --compiletest-rustc-args --no-doc --doc --bless --extra-checks --force-rerun --only-modified --compare-mode --pass --run --rustfix-coverage --no-capture --verbose --incremental --config --build-dir --build --host --target --exclude --skip --include-default-paths --rustc-error-format --on-fail --dry-run --dump-bootstrap-shims --stage --keep-stage --keep-stage-std --src --jobs --warnings --json-output --compile-time-deps --color --bypass-bootstrap-lock --rust-profile-generate --rust-profile-use --llvm-profile-use --llvm-profile-generate --enable-bolt-settings --skip-stage0-validation --reproducible-artifact --set --ci --skip-std-check-if-no-download-rustc --help [PATHS]... [ARGS]..."
+            opts="-v -i -j -h --no-fail-fast --test-args --compiletest-rustc-args --no-doc --doc --bless --extra-checks --force-rerun --only-modified --compare-mode --pass --run --rustfix-coverage --no-capture --test-codegen-backend --verbose --incremental --config --build-dir --build --host --target --exclude --skip --include-default-paths --rustc-error-format --on-fail --dry-run --dump-bootstrap-shims --stage --keep-stage --keep-stage-std --src --jobs --warnings --json-output --compile-time-deps --color --bypass-bootstrap-lock --rust-profile-generate --rust-profile-use --llvm-profile-use --llvm-profile-generate --enable-bolt-settings --skip-stage0-validation --reproducible-artifact --set --ci --skip-std-check-if-no-download-rustc --help [PATHS]... [ARGS]..."
             if [[ ${cur} == -* || ${COMP_CWORD} -eq 2 ]] ; then
                 COMPREPLY=( $(compgen -W "${opts}" -- "${cur}") )
                 return 0
@@ -3905,6 +3905,10 @@ _x() {
                     COMPREPLY=($(compgen -f "${cur}"))
                     return 0
                     ;;
+                --test-codegen-backend)
+                    COMPREPLY=($(compgen -f "${cur}"))
+                    return 0
+                    ;;
                 --config)
                     local oldifs
                     if [ -n "${IFS+x}" ]; then
diff --git a/src/etc/completions/x.zsh b/src/etc/completions/x.zsh
index 49139e70f7f..29237ef9bf8 100644
--- a/src/etc/completions/x.zsh
+++ b/src/etc/completions/x.zsh
@@ -351,6 +351,7 @@ _arguments "${_arguments_options[@]}" : \
 '--compare-mode=[mode describing what file the actual ui output will be compared to]:COMPARE MODE:_default' \
 '--pass=[force {check,build,run}-pass tests to this mode]:check | build | run:_default' \
 '--run=[whether to execute run-* tests]:auto | always | never:_default' \
+'--test-codegen-backend=[Use a different codegen backend when running tests]:TEST_CODEGEN_BACKEND:_default' \
 '--config=[TOML configuration file for build]:FILE:_files' \
 '--build-dir=[Build directory, overrides \`build.build-dir\` in \`bootstrap.toml\`]:DIR:_files -/' \
 '--build=[host target of the stage0 compiler]:BUILD:' \
diff --git a/src/librustdoc/html/static/js/search.js b/src/librustdoc/html/static/js/search.js
index d55208150b8..42b87d56252 100644
--- a/src/librustdoc/html/static/js/search.js
+++ b/src/librustdoc/html/static/js/search.js
@@ -5252,7 +5252,7 @@ if (typeof window !== "undefined") {
         },
         loadTreeByHash: hashHex => {
             const script = document.createElement("script");
-            script.src = `${ROOT_PATH}/search.index/${hashHex}.js`;
+            script.src = `${ROOT_PATH}search.index/${hashHex}.js`;
             script.onerror = e => {
                 if (databaseCallbacks) {
                     databaseCallbacks.err_rn_(hashHex, e);
@@ -5262,7 +5262,7 @@ if (typeof window !== "undefined") {
         },
         loadDataByNameAndHash: (name, hashHex) => {
             const script = document.createElement("script");
-            script.src = `${ROOT_PATH}/search.index/${name}/${hashHex}.js`;
+            script.src = `${ROOT_PATH}search.index/${name}/${hashHex}.js`;
             script.onerror = e => {
                 if (databaseCallbacks) {
                     databaseCallbacks.err_rd_(hashHex, e);
diff --git a/src/tools/clippy/clippy_lints/src/duplicate_mod.rs b/src/tools/clippy/clippy_lints/src/duplicate_mod.rs
index ce551a64d99..759b7b6837b 100644
--- a/src/tools/clippy/clippy_lints/src/duplicate_mod.rs
+++ b/src/tools/clippy/clippy_lints/src/duplicate_mod.rs
@@ -63,7 +63,7 @@ impl_lint_pass!(DuplicateMod => [DUPLICATE_MOD]);
 
 impl EarlyLintPass for DuplicateMod {
     fn check_item(&mut self, cx: &EarlyContext<'_>, item: &Item) {
-        if let ItemKind::Mod(_, _, ModKind::Loaded(_, Inline::No, mod_spans, _)) = &item.kind
+        if let ItemKind::Mod(_, _, ModKind::Loaded(_, Inline::No { .. }, mod_spans)) = &item.kind
             && let FileName::Real(real) = cx.sess().source_map().span_to_filename(mod_spans.inner_span)
             && let Some(local_path) = real.into_local_path()
             && let Ok(absolute_path) = local_path.canonicalize()
diff --git a/src/tools/clippy/clippy_lints/src/empty_line_after.rs b/src/tools/clippy/clippy_lints/src/empty_line_after.rs
index 3bd74856165..76e67b1154b 100644
--- a/src/tools/clippy/clippy_lints/src/empty_line_after.rs
+++ b/src/tools/clippy/clippy_lints/src/empty_line_after.rs
@@ -442,7 +442,7 @@ impl EmptyLineAfter {
                 None => span.shrink_to_lo(),
             },
             mod_items: match kind {
-                ItemKind::Mod(_, _, ModKind::Loaded(items, _, _, _)) => items
+                ItemKind::Mod(_, _, ModKind::Loaded(items, _, _)) => items
                     .iter()
                     .filter(|i| !matches!(i.span.ctxt().outer_expn_data().kind, ExpnKind::AstPass(_)))
                     .map(|i| i.id)
diff --git a/src/tools/clippy/clippy_lints/src/excessive_nesting.rs b/src/tools/clippy/clippy_lints/src/excessive_nesting.rs
index 1d3ae894944..5368701c304 100644
--- a/src/tools/clippy/clippy_lints/src/excessive_nesting.rs
+++ b/src/tools/clippy/clippy_lints/src/excessive_nesting.rs
@@ -164,7 +164,7 @@ impl Visitor<'_> for NestingVisitor<'_, '_> {
         }
 
         match &item.kind {
-            ItemKind::Trait(_) | ItemKind::Impl(_) | ItemKind::Mod(.., ModKind::Loaded(_, Inline::Yes, _, _)) => {
+            ItemKind::Trait(_) | ItemKind::Impl(_) | ItemKind::Mod(.., ModKind::Loaded(_, Inline::Yes, _)) => {
                 self.nest_level += 1;
 
                 if !self.check_indent(item.span, item.id) {
diff --git a/src/tools/clippy/clippy_utils/src/ast_utils/mod.rs b/src/tools/clippy/clippy_utils/src/ast_utils/mod.rs
index 24e017f7cf7..d80a9d9dd07 100644
--- a/src/tools/clippy/clippy_utils/src/ast_utils/mod.rs
+++ b/src/tools/clippy/clippy_utils/src/ast_utils/mod.rs
@@ -403,7 +403,7 @@ pub fn eq_item_kind(l: &ItemKind, r: &ItemKind) -> bool {
             ls == rs
                 && eq_id(*li, *ri)
                 && match (lmk, rmk) {
-                    (ModKind::Loaded(litems, linline, _, _), ModKind::Loaded(ritems, rinline, _, _)) => {
+                    (ModKind::Loaded(litems, linline, _), ModKind::Loaded(ritems, rinline, _)) => {
                         linline == rinline && over(litems, ritems, |l, r| eq_item(l, r, eq_item_kind))
                     },
                     (ModKind::Unloaded, ModKind::Unloaded) => true,
diff --git a/src/tools/compiletest/src/common.rs b/src/tools/compiletest/src/common.rs
index 2d49b1a7097..7fc80c1edb1 100644
--- a/src/tools/compiletest/src/common.rs
+++ b/src/tools/compiletest/src/common.rs
@@ -692,7 +692,9 @@ pub struct Config {
     pub minicore_path: Utf8PathBuf,
 
     /// Current codegen backend used.
-    pub codegen_backend: CodegenBackend,
+    pub default_codegen_backend: CodegenBackend,
+    /// Name/path of the backend to use instead of `default_codegen_backend`.
+    pub override_codegen_backend: Option<String>,
 }
 
 impl Config {
@@ -796,7 +798,8 @@ impl Config {
             profiler_runtime: Default::default(),
             diff_command: Default::default(),
             minicore_path: Default::default(),
-            codegen_backend: CodegenBackend::Llvm,
+            default_codegen_backend: CodegenBackend::Llvm,
+            override_codegen_backend: None,
         }
     }
 
diff --git a/src/tools/compiletest/src/directives.rs b/src/tools/compiletest/src/directives.rs
index 13e694b7f03..00007aa1d66 100644
--- a/src/tools/compiletest/src/directives.rs
+++ b/src/tools/compiletest/src/directives.rs
@@ -1624,7 +1624,7 @@ fn ignore_backends(
                 }
             }
         }) {
-            if config.codegen_backend == backend {
+            if config.default_codegen_backend == backend {
                 return IgnoreDecision::Ignore {
                     reason: format!("{} backend is marked as ignore", backend.as_str()),
                 };
@@ -1651,12 +1651,12 @@ fn needs_backends(
                     panic!("Invalid needs-backends value `{backend}` in `{path}`: {error}")
                 }
             })
-            .any(|backend| config.codegen_backend == backend)
+            .any(|backend| config.default_codegen_backend == backend)
         {
             return IgnoreDecision::Ignore {
                 reason: format!(
                     "{} backend is not part of required backends",
-                    config.codegen_backend.as_str()
+                    config.default_codegen_backend.as_str()
                 ),
             };
         }
diff --git a/src/tools/compiletest/src/directives/directive_names.rs b/src/tools/compiletest/src/directives/directive_names.rs
index f7955429d83..59690ff2602 100644
--- a/src/tools/compiletest/src/directives/directive_names.rs
+++ b/src/tools/compiletest/src/directives/directive_names.rs
@@ -194,6 +194,7 @@ pub(crate) const KNOWN_DIRECTIVE_NAMES: &[&str] = &[
     "only-bpf",
     "only-cdb",
     "only-dist",
+    "only-eabihf",
     "only-elf",
     "only-emscripten",
     "only-gnu",
diff --git a/src/tools/compiletest/src/lib.rs b/src/tools/compiletest/src/lib.rs
index f5409e78341..469dd68207e 100644
--- a/src/tools/compiletest/src/lib.rs
+++ b/src/tools/compiletest/src/lib.rs
@@ -212,9 +212,15 @@ pub fn parse_config(args: Vec<String>) -> Config {
         )
         .optopt(
             "",
-            "codegen-backend",
+            "default-codegen-backend",
             "the codegen backend currently used",
             "CODEGEN BACKEND NAME",
+        )
+        .optopt(
+            "",
+            "override-codegen-backend",
+            "the codegen backend to use instead of the default one",
+            "CODEGEN BACKEND [NAME | PATH]",
         );
 
     let (argv0, args_) = args.split_first().unwrap();
@@ -276,14 +282,17 @@ pub fn parse_config(args: Vec<String>) -> Config {
             || directives::extract_llvm_version_from_binary(&matches.opt_str("llvm-filecheck")?),
         );
 
-    let codegen_backend = match matches.opt_str("codegen-backend").as_deref() {
+    let default_codegen_backend = match matches.opt_str("default-codegen-backend").as_deref() {
         Some(backend) => match CodegenBackend::try_from(backend) {
             Ok(backend) => backend,
-            Err(error) => panic!("invalid value `{backend}` for `--codegen-backend`: {error}"),
+            Err(error) => {
+                panic!("invalid value `{backend}` for `--defalt-codegen-backend`: {error}")
+            }
         },
         // By default, it's always llvm.
         None => CodegenBackend::Llvm,
     };
+    let override_codegen_backend = matches.opt_str("override-codegen-backend");
 
     let run_ignored = matches.opt_present("ignored");
     let with_rustc_debug_assertions = matches.opt_present("with-rustc-debug-assertions");
@@ -472,7 +481,8 @@ pub fn parse_config(args: Vec<String>) -> Config {
 
         minicore_path: opt_path(matches, "minicore-path"),
 
-        codegen_backend,
+        default_codegen_backend,
+        override_codegen_backend,
     }
 }
 
@@ -812,13 +822,13 @@ fn collect_tests_from_dir(
         && let Some(Utf8Component::Normal(parent)) = components.next()
         && parent == "tests"
         && let Ok(backend) = CodegenBackend::try_from(backend)
-        && backend != cx.config.codegen_backend
+        && backend != cx.config.default_codegen_backend
     {
         // We ignore asm tests which don't match the current codegen backend.
         warning!(
             "Ignoring tests in `{dir}` because they don't match the configured codegen \
              backend (`{}`)",
-            cx.config.codegen_backend.as_str(),
+            cx.config.default_codegen_backend.as_str(),
         );
         return Ok(TestCollector::new());
     }
diff --git a/src/tools/compiletest/src/runtest.rs b/src/tools/compiletest/src/runtest.rs
index 821cb128647..2402ed9a950 100644
--- a/src/tools/compiletest/src/runtest.rs
+++ b/src/tools/compiletest/src/runtest.rs
@@ -1558,6 +1558,11 @@ impl<'test> TestCx<'test> {
             rustc.arg("--sysroot").arg(&self.config.sysroot_base);
         }
 
+        // If the provided codegen backend is not LLVM, we need to pass it.
+        if let Some(ref backend) = self.config.override_codegen_backend {
+            rustc.arg(format!("-Zcodegen-backend={}", backend));
+        }
+
         // Optionally prevent default --target if specified in test compile-flags.
         let custom_target = self.props.compile_flags.iter().any(|x| x.starts_with("--target"));
 
diff --git a/src/tools/miri/tests/panic/oob_subslice.stderr b/src/tools/miri/tests/panic/oob_subslice.stderr
index f8270f4ad4d..e1e5bd33d31 100644
--- a/src/tools/miri/tests/panic/oob_subslice.stderr
+++ b/src/tools/miri/tests/panic/oob_subslice.stderr
@@ -1,5 +1,5 @@
 
 thread 'main' ($TID) panicked at tests/panic/oob_subslice.rs:LL:CC:
-range end index 5 out of range for slice of length 4
+range end index 4 out of range for slice of length 4
 note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
 note: in Miri, you may have to set `MIRIFLAGS=-Zmiri-env-forward=RUST_BACKTRACE` for the environment variable to have an effect
diff --git a/src/tools/rustfmt/src/items.rs b/src/tools/rustfmt/src/items.rs
index 10df6f96702..6555679c394 100644
--- a/src/tools/rustfmt/src/items.rs
+++ b/src/tools/rustfmt/src/items.rs
@@ -3600,7 +3600,7 @@ pub(crate) fn rewrite_extern_crate(
 pub(crate) fn is_mod_decl(item: &ast::Item) -> bool {
     !matches!(
         item.kind,
-        ast::ItemKind::Mod(_, _, ast::ModKind::Loaded(_, ast::Inline::Yes, _, _))
+        ast::ItemKind::Mod(_, _, ast::ModKind::Loaded(_, ast::Inline::Yes, _))
     )
 }
 
diff --git a/src/tools/rustfmt/src/modules.rs b/src/tools/rustfmt/src/modules.rs
index 3bc656b64b3..af9feccb32e 100644
--- a/src/tools/rustfmt/src/modules.rs
+++ b/src/tools/rustfmt/src/modules.rs
@@ -316,11 +316,12 @@ impl<'ast, 'psess, 'c> ModResolver<'ast, 'psess> {
             self.directory = directory;
         }
         match (sub_mod.ast_mod_kind, sub_mod.items) {
-            (Some(Cow::Borrowed(ast::ModKind::Loaded(items, _, _, _))), _) => {
+            (Some(Cow::Borrowed(ast::ModKind::Loaded(items, _, _))), _) => {
                 self.visit_mod_from_ast(items)
             }
-            (Some(Cow::Owned(ast::ModKind::Loaded(items, _, _, _))), _)
-            | (_, Cow::Owned(items)) => self.visit_mod_outside_ast(items),
+            (Some(Cow::Owned(ast::ModKind::Loaded(items, _, _))), _) | (_, Cow::Owned(items)) => {
+                self.visit_mod_outside_ast(items)
+            }
             (_, _) => Ok(()),
         }
     }
diff --git a/src/tools/rustfmt/src/visitor.rs b/src/tools/rustfmt/src/visitor.rs
index 23d07c930d9..a3acbb218ff 100644
--- a/src/tools/rustfmt/src/visitor.rs
+++ b/src/tools/rustfmt/src/visitor.rs
@@ -942,7 +942,7 @@ impl<'b, 'a: 'b> FmtVisitor<'a> {
         let ident_str = rewrite_ident(&self.get_context(), ident).to_owned();
         self.push_str(&ident_str);
 
-        if let ast::ModKind::Loaded(ref items, ast::Inline::Yes, ref spans, _) = mod_kind {
+        if let ast::ModKind::Loaded(ref items, ast::Inline::Yes, ref spans) = mod_kind {
             let ast::ModSpans {
                 inner_span,
                 inject_use_span: _,
diff --git a/src/tools/tidy/src/deps.rs b/src/tools/tidy/src/deps.rs
index 858b058cb7d..80b6d54ce1c 100644
--- a/src/tools/tidy/src/deps.rs
+++ b/src/tools/tidy/src/deps.rs
@@ -592,6 +592,8 @@ pub fn check(root: &Path, cargo: &Path, bless: bool, bad: &mut bool) {
 
         if workspace == "library" {
             check_runtime_license_exceptions(&metadata, bad);
+            check_runtime_no_duplicate_dependencies(&metadata, bad);
+            check_runtime_no_proc_macros(&metadata, bad);
             checked_runtime_licenses = true;
         }
     }
@@ -790,6 +792,37 @@ fn check_license_exceptions(
     }
 }
 
+fn check_runtime_no_duplicate_dependencies(metadata: &Metadata, bad: &mut bool) {
+    let mut seen_pkgs = HashSet::new();
+    for pkg in &metadata.packages {
+        if pkg.source.is_none() {
+            continue;
+        }
+
+        if !seen_pkgs.insert(&*pkg.name) {
+            tidy_error!(
+                bad,
+                "duplicate package `{}` is not allowed for the standard library",
+                pkg.name
+            );
+        }
+    }
+}
+
+fn check_runtime_no_proc_macros(metadata: &Metadata, bad: &mut bool) {
+    for pkg in &metadata.packages {
+        if pkg.targets.iter().any(|target| target.is_proc_macro()) {
+            tidy_error!(
+                bad,
+                "proc macro `{}` is not allowed as standard library dependency.\n\
+                Using proc macros in the standard library would break cross-compilation \
+                as proc-macros don't get shipped for the host tuple.",
+                pkg.name
+            );
+        }
+    }
+}
+
 /// Checks the dependency of `restricted_dependency_crates` at the given path. Changes `bad` to
 /// `true` if a check failed.
 ///