Add deprecated_safe feature gate and attribute, cc #94978

2 files changed, 7 insertions, 0 deletions

diff --git a/compiler/rustc_feature/src/active.rs b/compiler/rustc_feature/src/active.rs
index d9748b19e13..02cdaa3b958 100644
--- a/compiler/rustc_feature/src/active.rs
+++ b/compiler/rustc_feature/src/active.rs
@@ -364,6 +364,8 @@ declare_features! (
     (active, default_alloc_error_handler, "1.48.0", Some(66741), None),
     /// Allows default type parameters to influence type inference.
     (active, default_type_parameter_fallback, "1.3.0", Some(27336), None),
+    /// Allows using `#[deprecated_safe]` to deprecate the safeness of a function or trait
+    (active, deprecated_safe, "1.61.0", Some(94978), None),
     /// Allows having using `suggestion` in the `#[deprecated]` attribute.
     (active, deprecated_suggestion, "1.61.0", Some(94785), None),
     /// Allows `#[derive(Default)]` and `#[default]` on enums.
diff --git a/compiler/rustc_feature/src/builtin_attrs.rs b/compiler/rustc_feature/src/builtin_attrs.rs
index 9c7b8f80324..e2f0b413ff3 100644
--- a/compiler/rustc_feature/src/builtin_attrs.rs
+++ b/compiler/rustc_feature/src/builtin_attrs.rs
@@ -452,6 +452,11 @@ pub const BUILTIN_ATTRIBUTES: &[BuiltinAttribute] = &[
         "`default_method_body_is_const` is a temporary placeholder for declaring default bodies \
         as `const`, which may be removed or renamed in the future."
     ),
+    // lang-team MCP 147
+    gated!(
+        deprecated_safe, Normal, template!(List: r#"since = "version", note = "...""#), ErrorFollowing,
+        experimental!(deprecated_safe),
+    ),
 
     // ==========================================================================
     // Internal attributes: Stability, deprecation, and unsafe: