Run clippy with only the declared syn features

Author: meithecatte

.github/workflows/rust.yml

@@ -21,7 +21,8 @@ jobs:
         toolchain: ${{ matrix.rust }}
         profile: minimal
         default: true
-    - run: cargo build
+    - uses: taiki-e/install-action@cargo-hack
+    - run: cargo hack build --feature-powerset
     - run: cargo test --all ${{ matrix.extra-test-opts }}
   clippy:
     runs-on: ubuntu-latest
@@ -33,4 +34,5 @@ jobs:
         toolchain: nightly
         override: true
         components: clippy
-    - run: cargo clippy --all --all-targets -- -D warnings
+    - uses: taiki-e/install-action@cargo-hack
+    - run: cargo hack clippy --workspace -- -D warnings