From a4eba4f79a98dc0035d446ad88ac05fcec740453 Mon Sep 17 00:00:00 2001
From: Amanieu d'Antras <amanieu@gmail.com>
Date: Thu, 30 May 2019 21:06:32 +0100
Subject: [PATCH] Fix the bounds on K for the Send impl of IterMut

---
 src/map.rs | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/map.rs b/src/map.rs
index 6017295759..ad5602a997 100644
--- a/src/map.rs
+++ b/src/map.rs
@@ -1119,6 +1119,11 @@ pub struct IterMut<'a, K, V> {
     marker: PhantomData<(&'a K, &'a mut V)>,
 }
 
+// We override the default Send impl which has K: Sync instead of K: Send. Both
+// are correct, but this one is more general since it allows keys which
+// implement Send but not Sync.
+unsafe impl<K: Send, V: Send> Send for IterMut<'_, K, V> {}
+
 impl<K, V> IterMut<'_, K, V> {
     /// Returns a iterator of references over the remaining items.
     #[inline]