diff --git a/library/alloc/src/borrow.rs b/library/alloc/src/borrow.rs
index 904a53bb4ac..83a1385599b 100644
--- a/library/alloc/src/borrow.rs
+++ b/library/alloc/src/borrow.rs
@@ -21,7 +21,6 @@ use Cow::*;
 impl<'a, B: ?Sized> Borrow<B> for Cow<'a, B>
 where
     B: ToOwned,
-    <B as ToOwned>::Owned: 'a,
 {
     fn borrow(&self) -> &B {
         &**self