From 74b4312a32b98b68a59c9401ba92ea65246c57dc Mon Sep 17 00:00:00 2001
From: Josh Stone <cuviper@gmail.com>
Date: Tue, 8 Feb 2022 17:14:59 -0800
Subject: [PATCH] impl Debug for IterMut and ValuesMut

(cherry picked from commit 4ddce3a976c1bc88a6373391da542729c4bb1815)
---
 RELEASES.md |  2 ++
 src/map.rs  | 14 ++++++++++++--
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/RELEASES.md b/RELEASES.md
index d556b677..1c1bf069 100644
--- a/RELEASES.md
+++ b/RELEASES.md
@@ -4,6 +4,8 @@
 
   - The `hashbrown` dependency has been updated to version 0.12.
 
+  - `IterMut` and `ValuesMut` now implement `Debug`.
+
 - 1.8.2
 
   - Bump the `rustc-rayon` dependency, for compiler use only.
diff --git a/src/map.rs b/src/map.rs
index 9e4d1113..4a24f04a 100644
--- a/src/map.rs
+++ b/src/map.rs
@@ -999,7 +999,12 @@ 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`.
 ///
@@ -1110,7 +1115,12 @@ 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`.
 ///