fn next_back(&mut self) -> Option<(&'a T)> { self.iter.next_back() }
}
-impl<'a, T> ExactSize<&'a T> for Items<'a, T> {}
+impl<'a, T> ExactSizeIterator<&'a T> for Items<'a, T> {}
/// An iterator that moves out of a `BinaryHeap`.
pub struct MoveItems<T> {