diff --git a/library/core/src/iter/traits/double_ended.rs b/library/core/src/iter/traits/double_ended.rs
index d370c16ea5a..16bee0e2eee 100644
--- a/library/core/src/iter/traits/double_ended.rs
+++ b/library/core/src/iter/traits/double_ended.rs
@@ -123,7 +123,7 @@ pub trait DoubleEndedIterator: Iterator {
     /// assert_eq!(iter.advance_back_by(100), Err(1)); // only `&3` was skipped
     /// ```
     #[inline]
-    #[unstable(feature = "iter_advance_by", reason = "recently added", issue = "none")]
+    #[unstable(feature = "iter_advance_by", reason = "recently added", issue = "77404")]
     fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
         for i in 0..n {
             self.next_back().ok_or(i)?;
diff --git a/library/core/src/iter/traits/iterator.rs b/library/core/src/iter/traits/iterator.rs
index 36d4a50856f..813afcc0ec6 100644
--- a/library/core/src/iter/traits/iterator.rs
+++ b/library/core/src/iter/traits/iterator.rs
@@ -314,7 +314,7 @@ pub trait Iterator {
     /// assert_eq!(iter.advance_by(100), Err(1)); // only `&4` was skipped
     /// ```
     #[inline]
-    #[unstable(feature = "iter_advance_by", reason = "recently added", issue = "none")]
+    #[unstable(feature = "iter_advance_by", reason = "recently added", issue = "77404")]
     fn advance_by(&mut self, n: usize) -> Result<(), usize> {
         for i in 0..n {
             self.next().ok_or(i)?;