1 files changed, 3 insertions, 0 deletions
diff --git a/src/libcore/ops.rs b/src/libcore/ops.rs
index 55ff3eb4d06..80232764ed4 100644
--- a/src/libcore/ops.rs
+++ b/src/libcore/ops.rs
@@ -1166,6 +1166,7 @@ impl<F,A,R> FnOnce<A,R> for F
 #[unstable(feature = "core",
            reason = "uncertain about variadic generics, input versus associated types")]
 #[cfg(not(stage0))]
+#[rustc_paren_sugar]
 pub trait Fn<Args> {
     type Output;
 
@@ -1178,6 +1179,7 @@ pub trait Fn<Args> {
 #[unstable(feature = "core",
            reason = "uncertain about variadic generics, input versus associated types")]
 #[cfg(not(stage0))]
+#[rustc_paren_sugar]
 pub trait FnMut<Args> {
     type Output;
 
@@ -1190,6 +1192,7 @@ pub trait FnMut<Args> {
 #[unstable(feature = "core",
            reason = "uncertain about variadic generics, input versus associated types")]
 #[cfg(not(stage0))]
+#[rustc_paren_sugar]
 pub trait FnOnce<Args> {
     type Output;