Revert stabilization of the #[coverage(..)] attribute

compiler/rustc_feature/src/accepted.rs

@@ -157,9 +157,6 @@ declare_features! (
     (accepted, const_refs_to_static, "1.83.0", Some(119618)),
     /// Allows implementing `Copy` for closures where possible (RFC 2132).
     (accepted, copy_closures, "1.26.0", Some(44490)),
-    /// Allows function attribute `#[coverage(on/off)]`, to control coverage
-    /// instrumentation of that function.
-    (accepted, coverage_attribute, "CURRENT_RUSTC_VERSION", Some(84605)),
     /// Allows `crate` in paths.
     (accepted, crate_in_paths, "1.30.0", Some(45477)),
     /// Allows users to provide classes for fenced code block using `class:classname`.

compiler/rustc_feature/src/builtin_attrs.rs

@@ -480,9 +480,10 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         template!(List: "address, kcfi, memory, thread"), DuplicatesOk,
         EncodeCrossCrate::No, experimental!(no_sanitize)
     ),
-    ungated!(
+    gated!(
         coverage, Normal, template!(OneOf: &[sym::off, sym::on]),
         ErrorPreceding, EncodeCrossCrate::No,
+        coverage_attribute, experimental!(coverage)
     ),
 
     ungated!(

compiler/rustc_feature/src/unstable.rs

@@ -447,6 +447,9 @@ declare_features! (
     (unstable, coroutine_clone, "1.65.0", Some(95360)),
     /// Allows defining coroutines.
     (unstable, coroutines, "1.21.0", Some(43122)),
+    /// Allows function attribute `#[coverage(on/off)]`, to control coverage
+    /// instrumentation of that function.
+    (unstable, coverage_attribute, "1.74.0", Some(84605)),
     /// Allows non-builtin attributes in inner attribute position.
     (unstable, custom_inner_attributes, "1.30.0", Some(54726)),
     /// Allows custom test frameworks with `#![test_runner]` and `#[test_case]`.

library/core/src/cmp.rs

@@ -348,7 +348,7 @@ pub trait Eq: PartialEq<Self> {
 #[rustc_builtin_macro]
 #[stable(feature = "builtin_macro_prelude", since = "1.38.0")]
 #[allow_internal_unstable(core_intrinsics, derive_eq, structural_match)]
-#[cfg_attr(bootstrap, allow_internal_unstable(coverage_attribute))]
+#[allow_internal_unstable(coverage_attribute)]
 pub macro Eq($item:item) {
     /* compiler built-in */
 }

library/core/src/lib.rs

@@ -107,13 +107,13 @@
 //
 // Library features:
 // tidy-alphabetical-start
-#![cfg_attr(bootstrap, feature(coverage_attribute))]
 #![cfg_attr(bootstrap, feature(do_not_recommend))]
 #![feature(array_ptr_get)]
 #![feature(asm_experimental_arch)]
 #![feature(const_eval_select)]
 #![feature(const_typed_swap)]
 #![feature(core_intrinsics)]
+#![feature(coverage_attribute)]
 #![feature(internal_impls_macro)]
 #![feature(ip)]
 #![feature(is_ascii_octdigit)]

library/core/src/macros/mod.rs

@@ -1673,8 +1673,7 @@ pub(crate) mod builtin {
     ///
     /// [the reference]: ../../../reference/attributes/testing.html#the-test-attribute
     #[stable(feature = "rust1", since = "1.0.0")]
-    #[allow_internal_unstable(test, rustc_attrs)]
-    #[cfg_attr(bootstrap, allow_internal_unstable(coverage_attribute))]
+    #[allow_internal_unstable(test, rustc_attrs, coverage_attribute)]
     #[rustc_builtin_macro]
     pub macro test($item:item) {
         /* compiler built-in */
@@ -1687,8 +1686,7 @@ pub(crate) mod builtin {
         soft,
         reason = "`bench` is a part of custom test frameworks which are unstable"
     )]
-    #[allow_internal_unstable(test, rustc_attrs)]
-    #[cfg_attr(bootstrap, allow_internal_unstable(coverage_attribute))]
+    #[allow_internal_unstable(test, rustc_attrs, coverage_attribute)]
     #[rustc_builtin_macro]
     pub macro bench($item:item) {
         /* compiler built-in */

src/doc/unstable-book/src/language-features/coverage-attribute.md

@@ -0,0 +1,30 @@
+# `coverage_attribute`
+
+The tracking issue for this feature is: [#84605]
+
+[#84605]: https://github.com/rust-lang/rust/issues/84605
+
+---
+
+The `coverage` attribute can be used to selectively disable coverage
+instrumentation in an annotated function. This might be useful to:
+
+-   Avoid instrumentation overhead in a performance critical function
+-   Avoid generating coverage for a function that is not meant to be executed,
+    but still target 100% coverage for the rest of the program.
+
+## Example
+
+```rust
+#![feature(coverage_attribute)]
+
+// `foo()` will get coverage instrumentation (by default)
+fn foo() {
+  // ...
+}
+
+#[coverage(off)]
+fn bar() {
+  // ...
+}
+```

src/tools/rust-analyzer/crates/hir-expand/src/inert_attr_macro.rs

@@ -237,7 +237,7 @@ pub const INERT_ATTRIBUTES: &[BuiltinAttribute] = &[
         template!(List: "address, kcfi, memory, thread"), DuplicatesOk,
         experimental!(no_sanitize)
     ),
-    ungated!(coverage, Normal, template!(Word, List: "on|off"), WarnFollowing),
+    gated!(coverage, Normal, template!(Word, List: "on|off"), WarnFollowing, coverage_attribute, experimental!(coverage)),
 
     ungated!(
         doc, Normal, template!(List: "hidden|inline|...", NameValueStr: "string"), DuplicatesOk