---

yaml
---
r: 143917
b: refs/heads/try2
c: 31f9b51
h: refs/heads/master
i:
  143915: 437b4f4
v: v3

Author: bblum

[refs]

@@ -5,7 +5,7 @@ refs/heads/snap-stage3: 78a7676898d9f80ab540c6df5d4c9ce35bb50463
 refs/heads/try: 519addf6277dbafccbb4159db4b710c37eaa2ec5
 refs/tags/release-0.1: 1f5c5126e96c79d22cb7862f75304136e204f105
 refs/heads/ndm: f3868061cd7988080c30d6d5bf352a5a5fe2460b
-refs/heads/try2: c8c09d40fc3e34b1e8cc2cd58fd644488aa71327
+refs/heads/try2: 31f9b5159297ffbc6da8f6e640cd6f4f8ed7c44d
 refs/heads/dist-snap: ba4081a5a8573875fed17545846f6f6902c8ba8d
 refs/tags/release-0.2: c870d2dffb391e14efb05aa27898f1f6333a9596
 refs/tags/release-0.3: b5f0d0f648d9a6153664837026ba1be43d3e2503

branches/try2/src/libstd/cell.rs

@@ -13,6 +13,7 @@
 #[missing_doc];
 
 use cast::transmute_mut;
+use unstable::finally::Finally;
 use prelude::*;
 
 /*
@@ -65,18 +66,17 @@ impl<T> Cell<T> {
 
     /// Calls a closure with a reference to the value.
     pub fn with_ref<R>(&self, op: &fn(v: &T) -> R) -> R {
-        let v = self.take();
-        let r = op(&v);
-        self.put_back(v);
-        r
+        do self.with_mut_ref |ptr| { op(ptr) }
     }
 
     /// Calls a closure with a mutable reference to the value.
     pub fn with_mut_ref<R>(&self, op: &fn(v: &mut T) -> R) -> R {
-        let mut v = self.take();
-        let r = op(&mut v);
-        self.put_back(v);
-        r
+        let mut v = Some(self.take());
+        do (|| {
+            op(v.get_mut_ref())
+        }).finally {
+            self.put_back(v.take_unwrap());
+        }
     }
 }