Implement is-checks against type variables.

tests/compiler/dart2js_extra/generics_factories_test.dart

Index: tests/compiler/dart2js_extra/generics_factories_test.dart
diff --git a/tests/compiler/dart2js_extra/generics_factories_test.dart b/tests/compiler/dart2js_extra/generics_factories_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..2de75016d583a9044035063795e812c3e67b5f85
--- /dev/null
+++ b/tests/compiler/dart2js_extra/generics_factories_test.dart
@@ -0,0 +1,22 @@
+// 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.
+
+// Test that factories are marked as needing rti.
+
+class A<T> {
+  foo(o) => o is T;
+  factory A.c() => new B<T>();
+  A();
+}
+
+class B<T> extends A<T> {}
+
+class C {}
+
+class D {}
+
+main() {
+  Expect.isTrue(new A<C>.c().foo(new C()));
+  Expect.isFalse(new A<C>.c().foo(new D()));
+}