diff --git a/library/core/src/slice/ascii.rs b/library/core/src/slice/ascii.rs
index 63715a6b86b..5e5399acc1b 100644
--- a/library/core/src/slice/ascii.rs
+++ b/library/core/src/slice/ascii.rs
@@ -215,8 +215,6 @@ fn next_back(&mut self) -> Option<u8> {
     }
 }
 #[stable(feature = "inherent_ascii_escape", since = "1.60.0")]
-impl<'a> iter::ExactSizeIterator for EscapeAscii<'a> {}
-#[stable(feature = "inherent_ascii_escape", since = "1.60.0")]
 impl<'a> iter::FusedIterator for EscapeAscii<'a> {}
 #[stable(feature = "inherent_ascii_escape", since = "1.60.0")]
 impl<'a> fmt::Display for EscapeAscii<'a> {