diff --git a/src/stream/stream/max_by.rs b/src/stream/stream/max_by.rs
index a41f49a..6cd9e56 100644
--- a/src/stream/stream/max_by.rs
+++ b/src/stream/stream/max_by.rs
@@ -31,7 +31,6 @@ impl<S, F, T> MaxByFuture<S, F, T> {
 impl<S, F> Future for MaxByFuture<S, F, S::Item>
 where
     S: Stream,
-    S::Item: Copy,
     F: FnMut(&S::Item, &S::Item) -> Ordering,
 {
     type Output = Option<S::Item>;