1 files changed, 15 insertions, 1 deletions
diff --git a/library/core/src/array/iter.rs b/library/core/src/array/iter.rs
index 5cecc4086d8..f4885ed9ffb 100644
--- a/library/core/src/array/iter.rs
+++ b/library/core/src/array/iter.rs
@@ -266,7 +266,7 @@ impl<T, const N: usize> Iterator for IntoIter<T, N> {
         Fold: FnMut(Acc, Self::Item) -> Acc,
     {
         let data = &mut self.data;
-        self.alive.by_ref().fold(init, |acc, idx| {
+        iter::ByRefSized(&mut self.alive).fold(init, |acc, idx| {
             // SAFETY: idx is obtained by folding over the `alive` range, which implies the
             // value is currently considered alive but as the range is being consumed each value
             // we read here will only be read once and then considered dead.
@@ -323,6 +323,20 @@ impl<T, const N: usize> DoubleEndedIterator for IntoIter<T, N> {
         })
     }
 
+    #[inline]
+    fn rfold<Acc, Fold>(mut self, init: Acc, mut rfold: Fold) -> Acc
+    where
+        Fold: FnMut(Acc, Self::Item) -> Acc,
+    {
+        let data = &mut self.data;
+        iter::ByRefSized(&mut self.alive).rfold(init, |acc, idx| {
+            // SAFETY: idx is obtained by folding over the `alive` range, which implies the
+            // value is currently considered alive but as the range is being consumed each value
+            // we read here will only be read once and then considered dead.
+            rfold(acc, unsafe { data.get_unchecked(idx).assume_init_read() })
+        })
+    }
+
     fn advance_back_by(&mut self, n: usize) -> Result<(), usize> {
         let len = self.len();