Fix the type of GcIndexMap::keys

Maybe we should try at least some basic testing...

Author: Techcable

src/hash_map/indexmap.rs

@@ -204,10 +204,10 @@ macro_rules! define_iterator {
  #[doc = concat!("An iterator over the ", $item_name, " of a [GcIndexMap]")]
  pub struct $name<'a, K: 'a, V: 'a>(core::slice::$wrapped<'a, Bucket<K, V>>);
  impl<'a, K: 'a, V: 'a> Iterator for $name<'a, K, V> {
- type Item = (&'a K, &'a V);
+ type Item = $item;
  #[inline]
  fn next(&mut self) -> Option<Self::Item> {
- self.0.next().map(|$bucket| (&$bucket.key, &$bucket.value))
+ self.0.next().map(|$bucket| $map)
  }
  #[inline]
  fn size_hint(&self) -> (usize, Option<usize>) {
@@ -217,7 +217,7 @@ macro_rules! define_iterator {
  impl<'a, K, V> DoubleEndedIterator for $name<'a, K, V> {
  #[inline]
  fn next_back(&mut self) -> Option<Self::Item> {
- self.0.next_back().map(|$bucket| (&$bucket.key, &$bucket.value))
+ self.0.next_back().map(|$bucket| $map)
  }
  }
  impl<'a, K, V> core::iter::ExactSizeIterator for $name<'a, K, V> {}