3 files changed, 16 insertions, 0 deletions
diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index 84bbc5a2973..f0cdb1e4e0f 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -56,6 +56,7 @@
 //! [`Rc`]: rc
 //! [`RefCell`]: core::cell
 
+#![allow(incomplete_features)]
 #![allow(unused_attributes)]
 #![stable(feature = "alloc", since = "1.36.0")]
 #![doc(
@@ -112,6 +113,7 @@
 #![feature(deprecated_suggestion)]
 #![feature(deref_pure_trait)]
 #![feature(dispatch_from_dyn)]
+#![feature(ergonomic_clones)]
 #![feature(error_generic_member_access)]
 #![feature(exact_size_is_empty)]
 #![feature(extend_one)]
diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index fe0b25f31b9..fc1cee28d03 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -245,6 +245,7 @@ use core::any::Any;
 use core::cell::Cell;
 #[cfg(not(no_global_oom_handling))]
 use core::clone::CloneToUninit;
+use core::clone::UseCloned;
 use core::cmp::Ordering;
 use core::hash::{Hash, Hasher};
 use core::intrinsics::abort;
@@ -2327,6 +2328,9 @@ impl<T: ?Sized, A: Allocator + Clone> Clone for Rc<T, A> {
     }
 }
 
+#[unstable(feature = "ergonomic_clones", issue = "132290")]
+impl<T: ?Sized, A: Allocator + Clone> UseCloned for Rc<T, A> {}
+
 #[cfg(not(no_global_oom_handling))]
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Default> Default for Rc<T> {
@@ -3490,6 +3494,9 @@ impl<T: ?Sized, A: Allocator + Clone> Clone for Weak<T, A> {
     }
 }
 
+#[unstable(feature = "ergonomic_clones", issue = "132290")]
+impl<T: ?Sized, A: Allocator + Clone> UseCloned for Weak<T, A> {}
+
 #[stable(feature = "rc_weak", since = "1.4.0")]
 impl<T: ?Sized, A: Allocator> fmt::Debug for Weak<T, A> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index faee15ab0c6..4999319f618 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -11,6 +11,7 @@
 use core::any::Any;
 #[cfg(not(no_global_oom_handling))]
 use core::clone::CloneToUninit;
+use core::clone::UseCloned;
 use core::cmp::Ordering;
 use core::hash::{Hash, Hasher};
 use core::intrinsics::abort;
@@ -2197,6 +2198,9 @@ impl<T: ?Sized, A: Allocator + Clone> Clone for Arc<T, A> {
     }
 }
 
+#[unstable(feature = "ergonomic_clones", issue = "132290")]
+impl<T: ?Sized, A: Allocator + Clone> UseCloned for Arc<T, A> {}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized, A: Allocator> Deref for Arc<T, A> {
     type Target = T;
@@ -3158,6 +3162,9 @@ impl<T: ?Sized, A: Allocator + Clone> Clone for Weak<T, A> {
     }
 }
 
+#[unstable(feature = "ergonomic_clones", issue = "132290")]
+impl<T: ?Sized, A: Allocator + Clone> UseCloned for Weak<T, A> {}
+
 #[stable(feature = "downgraded_weak", since = "1.10.0")]
 impl<T> Default for Weak<T> {
     /// Constructs a new `Weak<T>`, without allocating memory.