Use stable Rust for address sanitizer (#734)

* Use stable Rust for address sanitizer

Nightly is broken today, which blocks our CI. This is the third or
fourth time this has happened to us, so let's switch over to using the
RUSTC_BOOTSTRAP hack to use nightly features on stable Rust. This is
scoped only to the ASan makefile target, so it won't actually allow us
to use nightly features in our code, just when running the sanitizers.

Signed-off-by: James Bornholt <[email protected]>

* Install stable Rust

Signed-off-by: James Bornholt <[email protected]>

---------

Signed-off-by: James Bornholt <[email protected]>

.github/workflows/integration.yml

@@ -200,7 +200,7 @@ jobs:
     - name: Install nightly Rust
       uses: actions-rs/toolchain@v1
       with:
-        toolchain: nightly
+        toolchain: stable
         override: true
         components: rust-src
     - name: Restore Cargo cache

Makefile

@@ -27,7 +27,8 @@ test:
 test-asan-working:
 	@packages=`echo "$(CRATES)" | sed -E 's/(^| )/ -p /g'`; \
 	RUSTFLAGS="-Zsanitizer=address" \
-	cargo +nightly test -Z build-std --target x86_64-unknown-linux-gnu --features $(RUST_FEATURES) $$packages -- --ignored test_asan_working 2>&1 \
+	RUSTC_BOOTSTRAP=1 \
+	cargo test -Z build-std --target x86_64-unknown-linux-gnu --features $(RUST_FEATURES) $$packages -- --ignored test_asan_working 2>&1 \
 	| tee /dev/stderr \
 	| grep "heap-use-after-free" \
 	  && echo "ASan is working" || (echo "ASan did not find the use-after-free; something's wrong"; exit 1)
@@ -37,7 +38,8 @@ test-asan:
 	@packages=`echo "$(CRATES)" | sed -E 's/(^| )/ -p /g'`; \
 	LSAN_OPTIONS=suppressions="$$(pwd)/lsan-suppressions.txt" \
 	RUSTFLAGS="-Zsanitizer=address" \
-	cargo +nightly test -Z build-std --target x86_64-unknown-linux-gnu --features $(RUST_FEATURES) $$packages -- \
+	RUSTC_BOOTSTRAP=1 \
+	cargo test -Z build-std --target x86_64-unknown-linux-gnu --features $(RUST_FEATURES) $$packages -- \
 	--skip reftest_ \
 	--skip proptest_ \
 	--skip fork_test \