Ensure that type of the AssertAssignable instruction is recomputed.

tests/language/type_propagation_assert_assignable_test.dart

Index: tests/language/type_propagation_assert_assignable_test.dart
diff --git a/tests/language/type_propagation_assert_assignable_test.dart b/tests/language/type_propagation_assert_assignable_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..56089e60467bc4b2f2a419ae77acf8fbacb19afd
--- /dev/null
+++ b/tests/language/type_propagation_assert_assignable_test.dart
@@ -0,0 +1,44 @@
+// Copyright (c) 2013, 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.
+// Check that type of the AssertAssignable is recomputed correctly.
+
+import "package:expect/expect.dart";
+
+class A {
+  final p;
+  final _b;
+
+  b() {
+    try { return _b; } catch (e) { }
+  }
+
+  A(this.p, this._b);
+}
+
+class B extends A {
+  B(p, b) : super(p, b);
+}
+
+bar(v) {
+  for (var x = v; x != null; x = x.p) {
+    if (x.b()) {
+      return x;
+    }
+  }
+  return null;
+}
+
+foo(v) {
+  A x = bar(v);
+  return x != null;
+}
+
+main() {
+  final a = new A(new B(new A("haha", true), false), false);
+
+  for (var i = 0; i < 10000; i++) {
+    Expect.isTrue(foo(a));
+  }
+  Expect.isTrue(foo(a));
+}