Support runtime check of function types.

tests/language/function_subtype_cast3_test.dart

Index: tests/language/function_subtype_cast3_test.dart
diff --git a/tests/language/function_subtype_cast3_test.dart b/tests/language/function_subtype_cast3_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..ba6f4acfff9013f8f4d0e964ed5a3dcfd626b3db
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+++ b/tests/language/function_subtype_cast3_test.dart
@@ -0,0 +1,33 @@
+// 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.
+// Dart test program for constructors and initializers.
+
+// Check function subtyping casts.
+
+import 'package:expect/expect.dart';
+
+typedef void Foo<T>(T t);
+typedef void Bar(int i);
+
+class Class<T> {
+  test(bool expectedResult, var o, String typeName) {
+    void local() {
+      if (expectedResult) {
+        Expect.isNotNull(o as Foo<T>, "bar as Foo<$typeName>");
+      } else {
+        Expect.throws(() => o as Foo<T>, (e) => true, "bar as Foo<$typeName>");
+      }
+      Expect.isNotNull(o as Bar, "bar as Bar");
+    }
+    local();
+  }
+}
+
+void bar(int i) {}
+
+void main() {
+  new Class().test(true, bar, "dynamic");
+  new Class<int>().test(true, bar, "int");
+  new Class<bool>().test(false, bar, "bool");
+}