diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index 493cf3117edf6..45333f38d8fc3 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -2393,7 +2393,7 @@ impl<T: ?Sized> Clone for Weak<T> {
 }
 
 #[stable(feature = "rc_weak", since = "1.4.0")]
-impl<T: ?Sized + fmt::Debug> fmt::Debug for Weak<T> {
+impl<T: ?Sized> fmt::Debug for Weak<T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "(Weak)")
     }
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index b75e9a2f3c71e..a3422fb93c87a 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -303,7 +303,7 @@ impl<T: ?Sized + Unsize<U>, U: ?Sized> CoerceUnsized<Weak<U>> for Weak<T> {}
 impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Weak<U>> for Weak<T> {}
 
 #[stable(feature = "arc_weak", since = "1.4.0")]
-impl<T: ?Sized + fmt::Debug> fmt::Debug for Weak<T> {
+impl<T: ?Sized> fmt::Debug for Weak<T> {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
         write!(f, "(Weak)")
     }