Rollup merge of #37587 - ollie27:to_mut, r=alexcrichton

Jonathan Turner · web-flow · commit c5a8dd3f050b · 2016-11-05T08:47:15.000-04:00
Remove recursive call from Cow::to_mut

It seems to prevent it from being inlined.
diff --git a/src/libcollections/borrow.rs b/src/libcollections/borrow.rs
@@ -160,7 +160,10 @@ impl<'a, B: ?Sized> Cow<'a, B> where B: ToOwned {
         match *self {
             Borrowed(borrowed) => {
                 *self = Owned(borrowed.to_owned());
-                self.to_mut()
+                match *self {
+                    Borrowed(..) => unreachable!(),
+                    Owned(ref mut owned) => owned,
+                }
             }
             Owned(ref mut owned) => owned,
         }

Original file line number	Diff line number	Diff line change
`@@ -160,7 +160,10 @@ impl<'a, B: ?Sized> Cow<'a, B> where B: ToOwned {`
`160`	`160`	`match *self {`
`161`	`161`	`Borrowed(borrowed) => {`
`162`	`162`	`*self = Owned(borrowed.to_owned());`
`163`		`- self.to_mut()`
	`163`	`+ match *self {`
	`164`	`+ Borrowed(..) => unreachable!(),`
	`165`	`+ Owned(ref mut owned) => owned,`
	`166`	`+ }`
`164`	`167`	`}`
`165`	`168`	`Owned(ref mut owned) => owned,`
`166`	`169`	`}`