Gather test coverage with stable rust

.github/workflows/ci.yml

@@ -303,7 +303,7 @@ jobs:
         continue-on-error: true
       - uses: actions-rs/toolchain@v1
         with:
-          toolchain: nightly
+          toolchain: stable
           override: true
           profile: minimal
           components: llvm-tools-preview

src/lib.rs

@@ -20,7 +20,6 @@
     ),
     allow(unused_variables, unused_assignments)
 )))]
-#![cfg_attr(coverage, feature(no_coverage))] // used in src/test_hygiene.rs
 
 //! Rust bindings to the Python interpreter.
 //!

src/test_hygiene/mod.rs

@@ -1,9 +1,6 @@
 // The modules in this test are used to check PyO3 macro expansion is hygienic. By locating the test
 // inside the crate the global `::pyo3` namespace is not available, so in combination with
 // #[pyo3(crate = "crate")] this validates that all macro expansion respects the setting.
-//
-// The generated code is never executed (these tests are checking compile time correctness.)
-#![cfg_attr(coverage, no_coverage)]
 
 mod misc;
 mod pyclass;