Implement DerefMut for String

SimonSapin · SimonSapin · commit 2d34a531f4ef · 2015-07-13T16:21:43.000+02:00
`&amp;mut str` is rarely useful, but it is for e.g.
`AsciiExt::make_ascii_lowercase`.
diff --git a/src/libcollections/string.rs b/src/libcollections/string.rs
@@ -989,6 +989,14 @@ impl ops::Deref for String {
     }
 }
 
+#[stable(feature = "derefmut_for_string", since = "1.2.0")]
+impl ops::DerefMut for String {
+    #[inline]
+    fn deref_mut(&mut self) -> &mut str {
+        unsafe { mem::transmute(&mut self.vec[..]) }
+    }
+}
+
 /// Wrapper type providing a `&String` reference via `Deref`.
 #[unstable(feature = "collections")]
 #[deprecated(since = "1.2.0",

Original file line number	Diff line number	Diff line change
`@@ -989,6 +989,14 @@ impl ops::Deref for String {`
`989`	`989`	`}`
`990`	`990`	`}`
`991`	`991`
	`992`	`+#[stable(feature = "derefmut_for_string", since = "1.2.0")]`
	`993`	`+impl ops::DerefMut for String {`
	`994`	`+ #[inline]`
	`995`	`+ fn deref_mut(&mut self) -> &mut str {`
	`996`	`+ unsafe { mem::transmute(&mut self.vec[..]) }`
	`997`	`+ }`
	`998`	`+}`
	`999`	`+`
`992`	`1000`	/// Wrapper type providing a `&String` reference via `Deref`.
`993`	`1001`	`#[unstable(feature = "collections")]`
`994`	`1002`	`#[deprecated(since = "1.2.0",`