impl Debug for IterMut and ValuesMut

Author: cuviper

RELEASES.md

@@ -13,6 +13,8 @@
   - `IndexMap::get_index_mut` now returns `Option<(&K, &mut V)>`, changing
     the key part from `&mut K` to `&K`. There is also a new alternative
     `MutableKeys::get_index_mut2` to access the former behavior.
+
+  - `IterMut` and `ValuesMut` now implement `Debug`.
 
 
 - 1.8.0

src/map.rs

@@ -984,7 +984,12 @@ impl<K, V> ExactSizeIterator for ValuesMut<'_, K, V> {
 
 impl<K, V> FusedIterator for ValuesMut<'_, K, V> {}
 
-// TODO: `impl Debug for ValuesMut` once we have MSRV 1.53 for `slice::IterMut::as_slice`
+impl<K, V: fmt::Debug> fmt::Debug for ValuesMut<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.iter.as_slice().iter().map(Bucket::value_ref);
+        f.debug_list().entries(iter).finish()
+    }
+}
 
 /// An owning iterator over the values of a `IndexMap`.
 ///
@@ -1095,7 +1100,12 @@ impl<K, V> ExactSizeIterator for IterMut<'_, K, V> {
 
 impl<K, V> FusedIterator for IterMut<'_, K, V> {}
 
-// TODO: `impl Debug for IterMut` once we have MSRV 1.53 for `slice::IterMut::as_slice`
+impl<K: fmt::Debug, V: fmt::Debug> fmt::Debug for IterMut<'_, K, V> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        let iter = self.iter.as_slice().iter().map(Bucket::refs);
+        f.debug_list().entries(iter).finish()
+    }
+}
 
 /// An owning iterator over the entries of a `IndexMap`.
 ///