diff --git a/library/std/src/io/mod.rs b/library/std/src/io/mod.rs
index 766da2ed6264..754e22f22882 100644
--- a/library/std/src/io/mod.rs
+++ b/library/std/src/io/mod.rs
@@ -2471,7 +2471,6 @@ impl<R: Read> Iterator for Bytes<R> {
     }
 }
 
-#[stable(feature = "bufreader_size_hint", since = "1.51.0")]
 trait SizeHint {
     fn lower_bound(&self) -> usize;
 
@@ -2484,14 +2483,12 @@ trait SizeHint {
     }
 }
 
-#[stable(feature = "bufreader_size_hint", since = "1.51.0")]
 impl<T> SizeHint for T {
     default fn lower_bound(&self) -> usize {
         0
     }
 }
 
-#[stable(feature = "bufreader_size_hint", since = "1.51.0")]
 impl<T> SizeHint for BufReader<T> {
     fn lower_bound(&self) -> usize {
         self.buffer().len()