diff --git a/src/liballoc/collections/vec_deque.rs b/src/liballoc/collections/vec_deque.rs index 42c00fd121d..0bf573f5e25 100644 --- a/src/liballoc/collections/vec_deque.rs +++ b/src/liballoc/collections/vec_deque.rs @@ -2286,6 +2286,16 @@ impl<'a, T> Iterator for Iter<'a, T> { final_res } + fn nth(&mut self, n: usize) -> Option { + if n >= count(self.tail, self.head, self.ring.len()) { + self.tail = self.head; + None + } else { + self.tail = wrap_index(self.tail.wrapping_add(n), self.ring.len()); + self.next() + } + } + #[inline] fn last(mut self) -> Option<&'a T> { self.next_back() @@ -2404,6 +2414,16 @@ impl<'a, T> Iterator for IterMut<'a, T> { back.iter_mut().fold(accum, &mut f) } + fn nth(&mut self, n: usize) -> Option { + if n >= count(self.tail, self.head, self.ring.len()) { + self.tail = self.head; + None + } else { + self.tail = wrap_index(self.tail.wrapping_add(n), self.ring.len()); + self.next() + } + } + #[inline] fn last(mut self) -> Option<&'a mut T> { self.next_back()