diff --git a/src/libserialize/serialize.rs b/src/libserialize/serialize.rs
index 8e1229f9c43..8ef8c2b4c0a 100644
--- a/src/libserialize/serialize.rs
+++ b/src/libserialize/serialize.rs
@@ -911,5 +911,5 @@ impl<T: UseSpecializedDecodable> Decodable for T {
 impl<'a, T: ?Sized + Encodable> UseSpecializedEncodable for &'a T {}
 impl<T: ?Sized + Encodable> UseSpecializedEncodable for Box<T> {}
 impl<T: Decodable> UseSpecializedDecodable for Box<T> {}
-impl<'a, T: ?Sized + Decodable> UseSpecializedDecodable for &'a T {}
-impl<'a, T: ?Sized + Decodable> UseSpecializedDecodable for &'a [T] {}
+impl<'a, T: Decodable> UseSpecializedDecodable for &'a T {}
+impl<'a, T: Decodable> UseSpecializedDecodable for &'a [T] {}