Use prototype inheritance to reduce number of is check properties.

tests/compiler/dart2js/is_test_with_type_parameters_test.dart

Index: tests/compiler/dart2js/is_test_with_type_parameters_test.dart
diff --git a/tests/compiler/dart2js/is_test_with_type_parameters_test.dart b/tests/compiler/dart2js/is_test_with_type_parameters_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..76847d8ceabb91ca0a01e61ba98901259906692a
--- /dev/null
+++ b/tests/compiler/dart2js/is_test_with_type_parameters_test.dart
@@ -0,0 +1,44 @@
+// 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";
+
+// Tests that is-tests are also available for superclasses if the class is
+// never instantiated and not explicitly tested against.
+
+class A {
+}
+
+class B extends A {
+}
+
+class C<T> implements A {
+}
+
+class D<T,L> {
+}
+
+class F {
+}
+
+class E<T,L> extends D<L,T> {
+}
+
+class G extends F {
+}
+
+main () {
+  var l = [new A(), new B(), new C<E<G, G>>()];
+  Expect.isTrue(l[0] is A);
+  Expect.isTrue(l[1] is B);
+  Expect.isTrue(l[2] is C<D<F, G>>);
+  for (int i = 0; i < l.length; i++) {
+    var e = l[i];
+    Expect.isTrue(e is A);
+    Expect.equals(e is B, i == 1);
+    Expect.isFalse(e is C<String>);
+    Expect.equals(e is C<D<F, G>>, i == 2);
+  }
+}
+