diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index cd54b8cc5699..53da24409459 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -2495,7 +2495,7 @@ trait SizeHint {
 }
 
 #[stable(feature = "bufreader_size_hint", since = "1.51.0")]
-impl<T> SizeHint for T;
+impl<T> SizeHint for T {}
 
 #[stable(feature = "bufreader_size_hint", since = "1.51.0")]
 impl<T> SizeHint for BufReader<T> {