Make sure to bind a method to its receiver if it is stored in a temporary.

tests/language/async_this_bound_test.dart

+// Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+
+class A {
+  int a = -1;
+
+  @NoInline()
+  foo(ignored, val) {
+    Expect.equals(val, this.a);
+  }
+}
+
+testA() async {
+  var a = new A();
+  a.foo(await false, -1);
+  a.a = 0;
+  a.foo(await false, 0);
+}
+
+@NoInline()
+@AssumeDynamic()
+confuse(x) => x;
+
+class B {
+  var f;
+  @NoInline()
+  var b = 10;
+  B(this.f);
+
+  bar(x) => b;
+}
+
+foo(x) => 499;
+bar(x) => 42;
+
+change(x) {
+  x.f = (x) => 99;
+}
+
+testB() async {
+  var b = confuse(new B(foo));
+  Expect.equals(99, b.f(await change(b)));
+  var b2 = confuse(new B(bar));
+  Expect.equals(10, b2.f(await (b2.f = b2.bar)));
+}
+
+test() async {
+  await testA();
+  await testB();
+}
+
+void main() {
+  asyncStart();
+  test().then((_) => asyncEnd());
+}