anchor.diff:        : super(helper, astFactory);
   
     @override
  -  DartType buildErroneousTypeNotAPrefix(fasta.Identifier suffix) {
  -    // TODO: implement buildErroneousTypeNotAPrefix
  -    throw new UnimplementedError();
  -  }
  -
  -  @override
  -  Expression buildError(Arguments arguments,
  -      {bool isGetter: false, bool isSetter: false, int offset}) {
  -    // TODO: implement buildError
  -    throw new UnimplementedError();
  -  }
  -
  -  @override
     Expression buildSimpleRead() => astFactory.simpleIdentifier(token);
  -
  -  @override
  -  void printOn(StringSink sink) {
  -    sink.write(", name: ");
  -    sink.write(name.name);
  -  }
   }
   
   class AnalyzerUnresolvedNameGenerator extends AnalyzerExpressionGenerator
  
positive.code: 
    @override
    Expression buildSimpleRead() => astFactory.simpleIdentifier(token);
  
    @override
    void printOn(StringSink sink) {
      sink.write(", name: ");
      sink.write(name.name);
    }
  }
  
  class AnalyzerVariableUseGenerator extends AnalyzerExpressionGenerator
  
negative.code: }
  
  class AnalyzerUnlinkedNameGenerator extends AnalyzerExpressionGenerator
      with fasta.UnlinkedGenerator<Expression, Statement, Arguments> {
    @override
    final Token token;
  
  