Add tests for coverage attribute on trait functions

tests/coverage/attr/trait-impl-inherit.cov-map

@@ -0,0 +1,9 @@
+Function name: <trait_impl_inherit::S as trait_impl_inherit::T>::f
+Raw bytes (9): 0x[01, 01, 00, 01, 01, 11, 05, 02, 06]
+Number of files: 1
+- file 0 => global file 1
+Number of expressions: 0
+Number of file 0 mappings: 1
+- Code(Counter(0)) at (prev + 17, 5) to (start + 2, 6)
+Highest counter ID seen: c0
+

tests/coverage/attr/trait-impl-inherit.coverage

@@ -0,0 +1,26 @@
+   LL|       |#![feature(coverage_attribute)]
+   LL|       |// Checks that `#[coverage(..)]` in a trait method is not inherited in an
+   LL|       |// implementation.
+   LL|       |//@ edition: 2021
+   LL|       |//@ reference: attributes.coverage.trait-impl-inherit
+   LL|       |
+   LL|       |trait T {
+   LL|       |    #[coverage(off)]
+   LL|       |    fn f(&self) {
+   LL|       |        println!("default");
+   LL|       |    }
+   LL|       |}
+   LL|       |
+   LL|       |struct S;
+   LL|       |
+   LL|       |impl T for S {
+   LL|      1|    fn f(&self) {
+   LL|      1|        println!("impl S");
+   LL|      1|    }
+   LL|       |}
+   LL|       |
+   LL|       |#[coverage(off)]
+   LL|       |fn main() {
+   LL|       |    S.f();
+   LL|       |}
+

tests/coverage/attr/trait-impl-inherit.rs

@@ -0,0 +1,25 @@
+#![feature(coverage_attribute)]
+// Checks that `#[coverage(..)]` in a trait method is not inherited in an
+// implementation.
+//@ edition: 2021
+//@ reference: attributes.coverage.trait-impl-inherit
+
+trait T {
+    #[coverage(off)]
+    fn f(&self) {
+        println!("default");
+    }
+}
+
+struct S;
+
+impl T for S {
+    fn f(&self) {
+        println!("impl S");
+    }
+}
+
+#[coverage(off)]
+fn main() {
+    S.f();
+}

tests/ui/coverage-attr/no-coverage.rs

@@ -15,6 +15,12 @@ trait Trait {
     type T;
 
     type U;
+
+    #[coverage(off)] //~ ERROR attribute should be applied to a function definition or closure
+    fn f(&self);
+
+    #[coverage(off)] //~ ERROR attribute should be applied to a function definition or closure
+    fn g();
 }
 
 #[coverage(off)]
@@ -26,6 +32,9 @@ impl Trait for () {
 
     #[coverage(off)] //~ ERROR attribute should be applied to a function definition or closure
     type U = impl Trait; //~ ERROR unconstrained opaque type
+
+    fn f(&self) {}
+    fn g() {}
 }
 
 extern "C" {

tests/ui/coverage-attr/no-coverage.stderr

@@ -7,28 +7,28 @@ LL | / trait Trait {
 LL | |     #[coverage(off)]
 LL | |     const X: u32;
 ...  |
-LL | |     type U;
+LL | |     fn g();
 LL | | }
    | |_- not a function or closure
 
 error[E0788]: attribute should be applied to a function definition or closure
-  --> $DIR/no-coverage.rs:41:5
+  --> $DIR/no-coverage.rs:50:5
    |
 LL |     #[coverage(off)]
    |     ^^^^^^^^^^^^^^^^
 LL |     let _ = ();
    |     ----------- not a function or closure
 
 error[E0788]: attribute should be applied to a function definition or closure
-  --> $DIR/no-coverage.rs:45:9
+  --> $DIR/no-coverage.rs:54:9
    |
 LL |         #[coverage(off)]
    |         ^^^^^^^^^^^^^^^^
 LL |         () => (),
    |         -------- not a function or closure
 
 error[E0788]: attribute should be applied to a function definition or closure
-  --> $DIR/no-coverage.rs:49:5
+  --> $DIR/no-coverage.rs:58:5
    |
 LL |     #[coverage(off)]
    |     ^^^^^^^^^^^^^^^^
@@ -52,45 +52,61 @@ LL |     type T;
    |     ------- not a function or closure
 
 error[E0788]: attribute should be applied to a function definition or closure
-  --> $DIR/no-coverage.rs:24:5
+  --> $DIR/no-coverage.rs:19:5
+   |
+LL |     #[coverage(off)]
+   |     ^^^^^^^^^^^^^^^^
+LL |     fn f(&self);
+   |     ------------ not a function or closure
+
+error[E0788]: attribute should be applied to a function definition or closure
+  --> $DIR/no-coverage.rs:22:5
+   |
+LL |     #[coverage(off)]
+   |     ^^^^^^^^^^^^^^^^
+LL |     fn g();
+   |     ------- not a function or closure
+
+error[E0788]: attribute should be applied to a function definition or closure
+  --> $DIR/no-coverage.rs:30:5
    |
 LL |     #[coverage(off)]
    |     ^^^^^^^^^^^^^^^^
 LL |     type T = Self;
    |     -------------- not a function or closure
 
 error[E0788]: attribute should be applied to a function definition or closure
-  --> $DIR/no-coverage.rs:27:5
+  --> $DIR/no-coverage.rs:33:5
    |
 LL |     #[coverage(off)]
    |     ^^^^^^^^^^^^^^^^
 LL |     type U = impl Trait;
    |     -------------------- not a function or closure
 
 error[E0788]: attribute should be applied to a function definition or closure
-  --> $DIR/no-coverage.rs:32:5
+  --> $DIR/no-coverage.rs:41:5
    |
 LL |     #[coverage(off)]
    |     ^^^^^^^^^^^^^^^^
 LL |     static X: u32;
    |     -------------- not a function or closure
 
 error[E0788]: attribute should be applied to a function definition or closure
-  --> $DIR/no-coverage.rs:35:5
+  --> $DIR/no-coverage.rs:44:5
    |
 LL |     #[coverage(off)]
    |     ^^^^^^^^^^^^^^^^
 LL |     type T;
    |     ------- not a function or closure
 
 error: unconstrained opaque type
-  --> $DIR/no-coverage.rs:28:14
+  --> $DIR/no-coverage.rs:34:14
    |
 LL |     type U = impl Trait;
    |              ^^^^^^^^^^
    |
    = note: `U` must be used in combination with a concrete type within the same impl
 
-error: aborting due to 11 previous errors
+error: aborting due to 13 previous errors
 
 For more information about this error, try `rustc --explain E0788`.