anchor.diff:  class ExpressionBuilder
       extends GeneralizingAstVisitor /* <ast.Expression | Accessor> */ {
     final ExpressionScope scope;
  -  final ast.VariableDeclaration cascadeReceiver;
  -  ExpressionBuilder(this.scope, [this.cascadeReceiver]);
  +  ast.VariableDeclaration cascadeReceiver;
  +  ExpressionBuilder(this.scope);
   
     ast.Expression build(Expression node) {
       var result = node.accept(this);
  
positive.code: class TypeScope extends ReferenceScope {
    final Map<TypeParameterElement, ast.TypeParameter> localTypeParameters =
        <TypeParameterElement, ast.TypeParameter>{};
  
    TypeScope(ReferenceLevelLoader loader) : super(loader);
  
    String get location => '?';
  
  
negative.code:     // Add the 'values' field.
      var valuesFieldElement = element.fields.firstWhere(_isValuesField);
      ast.Field valuesField = scope.getMemberReference(valuesFieldElement);
      var enumType = classNode.rawType;
      valuesField.type = new ast.InterfaceType(
          scope.loader.getCoreClassReference('List'), <ast.DartType>[enumType]);
      valuesField.initializer = new ast.ListLiteral(
  