Auto merge of #102573 - RalfJung:mirisync, r=oli-obk

Miri sync

This is a Miri sync created with my experimental fork of josh. We should probably not merge this yet, but we can use this to check if the sync looks the way it should.

r? `@oli-obk`

.github/workflows/ci.yml

@@ -12,6 +12,9 @@ on:
   schedule:
     - cron: '5 15 * * *' # At 15:05 UTC every day.
 
+env:
+  CARGO_UNSTABLE_SPARSE_REGISTRY: 'true'
+
 jobs:
   build:
     runs-on: ${{ matrix.os }}
@@ -38,14 +41,6 @@ jobs:
         if: runner.os == 'Linux'
         run: echo "MIRIFLAGS=-Zmiri-tag-gc=1" >> $GITHUB_ENV
 
-      # We install gnu-tar because BSD tar is buggy on macOS builders of GHA.
-      # See <https://github.com/actions/cache/issues/403>.
-      - name: Install GNU tar
-        if: runner.os == 'macOS'
-        run: |
-          brew install gnu-tar
-          echo "/usr/local/opt/gnu-tar/libexec/gnubin" >> $GITHUB_PATH
-
       # Cache the global cargo directory, but NOT the local `target` directory which
       # we cannot reuse anyway when the nightly changes (and it grows quite large
       # over time).
@@ -62,15 +57,14 @@ jobs:
             # contains package information of crates installed via `cargo install`.
             ~/.cargo/.crates.toml
             ~/.cargo/.crates2.json
-          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock', 'cargo-miri/src/version.rs') }}
+          key: ${{ runner.os }}-cargo-${{ hashFiles('**/Cargo.lock') }}
           restore-keys: ${{ runner.os }}-cargo
 
-      - name: Install rustup-toolchain-install-master and xargo
-        if: ${{ steps.cache.outputs.cache-hit == 'false' }}
+      - name: Install rustup-toolchain-install-master
+        if: ${{ steps.cache-npm.outputs.cache-hit != 'true' }}
         shell: bash
         run: |
-          cargo install rustup-toolchain-install-master
-          cargo install xargo
+          cargo install -f rustup-toolchain-install-master
 
       - name: Install "master" toolchain
         shell: bash

CONTRIBUTING.md

@@ -38,7 +38,7 @@ for you. If you don't want all of these to happen, you can add individual `.auto
 ## Building and testing Miri
 
 Invoking Miri requires getting a bunch of flags right and setting up a custom
-sysroot with xargo. The `miri` script takes care of that for you. With the
+sysroot. The `miri` script takes care of that for you. With the
 build environment prepared, compiling Miri is just one command away:
 
 ```