Pin rustc nightly to nightly-2025-07-18 for miri tests

ShaharNaveh · web-flow · commit 4cf5b5bde8fe · 2025-07-19T11:21:29.000+02:00
Closes #5998
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
@@ -352,7 +352,7 @@ jobs:
       - uses: actions/checkout@v4
       - uses: dtolnay/rust-toolchain@master
         with:
-            toolchain: nightly
+            toolchain: nightly-2025-07-18 # TODO: Set to "nightly" once https://github.com/rust-lang/rust/issues/144168 is fixed
             components: miri
 
       - uses: Swatinem/rust-cache@v2
