VM can parse and ignore metadata

tests/language/metadata_lib.dart

Index: tests/language/metadata_lib.dart
===================================================================
--- tests/language/metadata_lib.dart	(revision 0)
+++ tests/language/metadata_lib.dart	(revision 0)
@@ -0,0 +1,13 @@
+// Copyright (c) 2012, 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.
+
+#library("metadata.dart");
+
+class Alien {
+  final String qwrrkz;
+  const Alien(this.qwrrkz);
+  const Alien.unknown() : qwrrkz = "???";
+}
+
+const Klingon = const Alien("Klingon");