diff --git a/library/core/src/iter/traits/collect.rs b/library/core/src/iter/traits/collect.rs
index 7b75ab96ee7..e6900742c31 100644
--- a/library/core/src/iter/traits/collect.rs
+++ b/library/core/src/iter/traits/collect.rs
@@ -267,8 +267,9 @@ pub trait IntoIterator {
     fn into_iter(self) -> Self::IntoIter;
 }
 
+#[rustc_const_unstable(feature = "const_intoiterator_identity", issue = "90603")]
 #[stable(feature = "rust1", since = "1.0.0")]
-impl<I: Iterator> IntoIterator for I {
+impl<I: ~const Iterator> const IntoIterator for I {
     type Item = I::Item;
     type IntoIter = I;