Add test.

Author: m-ou-se

src/test/ui/stability-attribute/stability-attribute-trait-impl.rs

@@ -1,4 +1,4 @@
-#![feature(staged_api)]
+#![feature(staged_api, never_type, c_unwind)]
 //~^ ERROR module has missing stability attribute
 
 #[stable(feature = "a", since = "1")]
@@ -23,6 +23,13 @@ impl StableTrait for UnstableType {}
 impl UnstableTrait for StableType {}
 
 #[unstable(feature = "h", issue = "none")]
+impl StableTrait for ! {}
+
+// Note: If C-unwind is stabilized, switch this to another (unstable) ABI.
+#[unstable(feature = "i", issue = "none")]
+impl StableTrait for extern "C-unwind" fn() {}
+
+#[unstable(feature = "j", issue = "none")]
 //~^ ERROR an `#[unstable]` annotation here has no effect [ineffective_unstable_trait_impl]
 impl StableTrait for StableType {}
 

src/test/ui/stability-attribute/stability-attribute-trait-impl.stderr

@@ -1,7 +1,7 @@
 error: an `#[unstable]` annotation here has no effect
-  --> $DIR/stability-attribute-trait-impl.rs:25:1
+  --> $DIR/stability-attribute-trait-impl.rs:32:1
    |
-LL | #[unstable(feature = "h", issue = "none")]
+LL | #[unstable(feature = "j", issue = "none")]
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: see issue #55436 <https://github.com/rust-lang/rust/issues/55436> for more information
@@ -10,7 +10,7 @@ LL | #[unstable(feature = "h", issue = "none")]
 error: module has missing stability attribute
   --> $DIR/stability-attribute-trait-impl.rs:1:1
    |
-LL | / #![feature(staged_api)]
+LL | / #![feature(staged_api, never_type, c_unwind)]
 LL | |
 LL | |
 LL | | #[stable(feature = "a", since = "1")]