test x clippy --stage 0 in ci

Author: jyn514

src/ci/docker/host-x86_64/mingw-check/Dockerfile

@@ -39,8 +39,14 @@ COPY host-x86_64/mingw-check/validate-toolstate.sh /scripts/
 COPY host-x86_64/mingw-check/validate-error-codes.sh /scripts/
 
 ENV RUN_CHECK_WITH_PARALLEL_QUERIES 1
+
+# Run clippy just to make sure it doesn't error out; we don't actually want to gate on the warnings
+# though.
+# Ideally we'd use stage 1, but that ICEs: https://github.com/rust-lang/rust-clippy/issues/11230
+
 ENV SCRIPT python3 ../x.py --stage 2 test src/tools/expand-yaml-anchors && \
            python3 ../x.py check --target=i686-pc-windows-gnu --host=i686-pc-windows-gnu && \
+           python3 ../x.py clippy --stage 0 -Awarnings && \
            python3 ../x.py build --stage 0 src/tools/build-manifest && \
            python3 ../x.py test --stage 0 src/tools/compiletest && \
            python3 ../x.py test --stage 0 core alloc std test proc_macro && \