deps: update loom to 0.4 (#452)

Author: taiki-e

.github/workflows/ci.yml

@@ -75,14 +75,11 @@ jobs:
   # Nightly
   nightly:
     name: nightly
-    env:
-      # Pin nightly to avoid being impacted by breakage
-      RUST_VERSION: nightly-2019-09-25
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
       - name: Install Rust
-        run: rustup update $RUST_VERSION && rustup default $RUST_VERSION
+        run: rustup update $nightly && rustup default $nightly
       - name: Test
         run: . ci/test-stable.sh test
 
@@ -130,14 +127,11 @@ jobs:
   # Loom
   loom:
     name: loom
-    env:
-      # Pin nightly to avoid being impacted by breakage
-      RUST_VERSION: nightly-2020-05-19
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2
       - name: Install Rust
-        run: rustup update $RUST_VERSION && rustup default $RUST_VERSION
+        run: rustup update $nightly && rustup default $nightly
       - name: Loom tests
         run: RUSTFLAGS="--cfg loom -Dwarnings" cargo test --lib
 
@@ -150,6 +144,8 @@ jobs:
       - nightly
       - minrust
       - cross
+      - tsan
+      - loom
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2

Cargo.toml

@@ -32,4 +32,4 @@ serde = { version = "1.0.60", optional = true, default-features = false, feature
 serde_test = "1.0"
 
 [target.'cfg(loom)'.dev-dependencies]
-loom = "0.3"
+loom = "0.4"