From 3eee486e270347f39e41f4429cdb253b40219b89 Mon Sep 17 00:00:00 2001
From: F001 <changchun.fan@qq.com>
Date: Thu, 7 Jun 2018 17:47:55 +0800
Subject: [PATCH] impl DerefMut for Cell<[T]>

---
 src/libcore/cell.rs | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/libcore/cell.rs b/src/libcore/cell.rs
index a85eee854509..7e2ece0f02c1 100644
--- a/src/libcore/cell.rs
+++ b/src/libcore/cell.rs
@@ -559,6 +559,16 @@ impl<T> Deref for Cell<[T]> {
     }
 }
 
+#[unstable(feature = "as_cell", issue="43038")]
+impl<T> DerefMut for Cell<[T]> {
+    #[inline]
+    fn deref_mut(&mut self) -> &mut [Cell<T>] {
+        unsafe {
+            &mut *(self as *mut Cell<[T]> as *mut [Cell<T>])
+        }
+    }
+}
+
 /// A mutable memory location with dynamically checked borrow rules
 ///
 /// See the [module-level documentation](index.html) for more.