Support runtime check of function types.

tests/language/function_subtype_not3_test.dart

+// 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 negative function subtyping tests.
+
+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() {
+      Expect.equals(expectedResult, o is! Foo<T>, "bar is! Foo<$typeName>");
+      Expect.isFalse(o is! Bar, "bar is! Bar");
+    }
+    local();
+  }
+}
+
+void bar(int i) {}
+
+void main() {
+  new Class().test(false, bar, "dynamic");
+  new Class<int>().test(false, bar, "int");
+  new Class<bool>().test(true, bar, "bool");
+}