Try to add nightly feature to CI

Fix stray "

.github/workflows/ci.yml

@@ -118,6 +118,16 @@ jobs:
               }
             msrv: "MSRV"
 
+          # Test the `nightly` feature
+          - rust: nightly
+            python-version: "3.10"
+            platform:
+              {
+                os: "ubuntu-latest",
+                python-architecture: "x64",
+                rust-target: "x86_64-unknown-linux-gnu",
+              }
+            extra_features: "nightly"
     steps:
       - uses: actions/checkout@v2
 
@@ -153,7 +163,7 @@ jobs:
           cargo update -p hashbrown:0.11.2 --precise 0.9.1
 
       - name: Build docs
-        run: cargo doc --no-deps --no-default-features --features full
+        run: cargo doc --no-deps --no-default-features --features "full ${{ matrix.extra_features }}"
 
       - name: Build (no features)
         run: cargo build --lib --tests --no-default-features
@@ -176,26 +186,26 @@ jobs:
           cargo test --no-default-features
 
       - name: Build (all additive features)
-        run: cargo build --lib --tests --no-default-features --features full
+        run: cargo build --lib --tests --no-default-features --features "full ${{ matrix.extra_features }}"
 
       - if: ${{ startsWith(matrix.python-version, 'pypy') }}
         name: Build PyPy (abi3-py37)
-        run: cargo build --lib --tests --no-default-features --features "abi3-py37 full"
+        run: cargo build --lib --tests --no-default-features --features "abi3-py37 full ${{ matrix.extra_features }}"
 
       # Run tests (except on PyPy, because no embedding API).
       - if: ${{ !startsWith(matrix.python-version, 'pypy') }}
         name: Test
-        run: cargo test --no-default-features --features full
+        run: cargo test --no-default-features --features "full ${{ matrix.extra_features }}"
 
       # Run tests again, but in abi3 mode
       - if: ${{ !startsWith(matrix.python-version, 'pypy') }}
         name: Test (abi3)
-        run: cargo test --no-default-features --features "abi3 full"
+        run: cargo test --no-default-features --features "abi3 full ${{ matrix.extra_features }}"
 
       # Run tests again, for abi3-py37 (the minimal Python version)
       - if: ${{ (!startsWith(matrix.python-version, 'pypy')) && (matrix.python-version != '3.7') }}
         name: Test (abi3-py37)
-        run: cargo test --no-default-features --features "abi3-py37 full"
+        run: cargo test --no-default-features --features "abi3-py37 full ${{ matrix.extra_features }}"
 
       - name: Test proc-macro code
         run: cargo test --manifest-path=pyo3-macros-backend/Cargo.toml

tests/test_compile_error.rs

@@ -7,6 +7,7 @@ fn test_compile_errors() {
     _test_compile_errors()
 }
 
+#[cfg(not(feature = "nightly"))]
 #[rustversion::nightly]
 #[test]
 fn test_compile_errors() {
@@ -15,6 +16,15 @@ fn test_compile_errors() {
     let _ = std::panic::catch_unwind(_test_compile_errors);
 }
 
+#[cfg(feature = "nightly")]
+#[rustversion::nightly]
+#[test]
+fn test_compile_errors() {
+    // nightly - don't care if test output is potentially wrong, to avoid churn in PyO3's CI thanks
+    // to diagnostics changing on nightly.
+    _test_compile_errors()
+}
+
 #[cfg(not(feature = "nightly"))]
 fn _test_compile_errors() {
     let t = trybuild::TestCases::new();