Add token invariant to DiagnosticReporter

pkg/compiler/lib/src/resolution/enum_creator.dart

 // 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.
 
 library dart2js.resolution.enum_creator;
 
 import '../common.dart';
 import '../core_types.dart' show
     CoreTypes;
 import '../dart_types.dart';
@@ skipping 162 matching lines @@
     return new LiteralMap(
         null, // Type arguments.
         new NodeList(symbolToken(Precedence.OPEN_CURLY_BRACKET_INFO),
                      linkedList(entries),
                      symbolToken(Precedence.CLOSE_CURLY_BRACKET_INFO),
                      ','),
         isConst ? keywordToken('const') : null);
   }
 }
 
+// TODO(johnniwinther): Avoid creating synthesized ASTs for enums when SSA is
+// removed.
 class EnumCreator {
   final DiagnosticReporter reporter;
   final CoreTypes coreTypes;
   final EnumClassElementX enumClass;
 
   EnumCreator(this.reporter, this.coreTypes, this.enumClass);
 
   void createMembers() {
     Enum node = enumClass.node;
     InterfaceType enumType = enumClass.thisType;
@@ skipping 109 matching lines @@
     EnumMethodElementX toString = new EnumMethodElementX('toString',
         enumClass, Modifiers.EMPTY, toStringNode);
     FunctionSignatureX toStringSignature = new FunctionSignatureX(
         type: new FunctionType(toString, stringType));
     toString.functionSignature = toStringSignature;
     enumClass.addMember(toString, reporter);
 
     enumClass.enumValues = enumValues;
   }
 }