Add a test to test that substitutions are emitted for classes that are only used as type arguments.

tests/language/type_argument_substitution_test.dart

Index: tests/language/type_argument_substitution_test.dart
diff --git a/tests/language/type_argument_substitution_test.dart b/tests/language/type_argument_substitution_test.dart
new file mode 100644
index 0000000000000000000000000000000000000000..1383c4f67778b0de7ebab7ee60b627c0ad32a188
--- /dev/null
+++ b/tests/language/type_argument_substitution_test.dart
@@ -0,0 +1,22 @@
+// Copyright (c) 2014, 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 substitutions are emitted for classes that are only used as
+// type arguments.
+
+import 'package:expect/expect.dart';
+
+class K {}
+
+class A<T> {}
+
+class B extends A<K> {}
+
+class X<T> {}
+
+main() {
+  var v = new DateTime.now().millisecondsSinceEpoch != 42
+    ? new X<B>() : new X<A<String>>();
+  Expect.isFalse(v is X<A<String>>);
+}