Support type literals as compile-time constants.

sdk/lib/_internal/compiler/implementation/resolved_visitor.dart

 // 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.
 
 part of dart2js;
 
 abstract class ResolvedVisitor<R> extends Visitor<R> {
   TreeElements elements;
 
   ResolvedVisitor(this.elements);
@@ skipping 42 matching lines @@
     }
   }
 
   R visitSuperSend(Send node);
   R visitOperatorSend(Send node);
   R visitGetterSend(Send node);
   R visitClosureSend(Send node);
   R visitDynamicSend(Send node);
   R visitForeignSend(Send node);
   R visitStaticSend(Send node);
-  abstract R visitTypeReferenceSend(Send node);
+  R visitTypeReferenceSend(Send node);
 
   void internalError(String reason, {Node node});
 
   R visitNode(Node node) {
     internalError("Unhandled node", node: node);
   }
 }