anchor.diff:  }
   
   class FixesResponse {
  -  final Fixes fixes;
  +  final List<ProblemFix> fixes;
   
     FixesResponse(List<AnalysisErrorFixes> analysisErrorFixes) :
       this.fixes = _convert(analysisErrorFixes);
  
positive.code: 
    Future<FixesResponse> getFixes(String src, int offset) async {
      var results = _getFixesImpl(src, offset);
  
      return results.then((fixes) {
          return new FixesResponse(fixes.fixes);
      });
    }
  
  
negative.code:   /**
     * Convert any non-string values from the contained maps.
     */
    static List<ProblemFix> _convert(List<AnalysisErrorFixes> list) {
      var problemsAndFixes = new List<ProblemFix>();
      list.forEach((analysisErrorFix)
          => problemsAndFixes.add(_convertAnalysisErrorFix(analysisErrorFix)));
  
      return problemsAndFixes;
    }
  
    static ProblemFix _convertAnalysisErrorFix(AnalysisErrorFixes analysisErrFix) {
      String problemMessage = analysisErrFix.error.message;
      int problemOffset = analysisErrFix.error.location.offset;
      int problemLength = analysisErrFix.error.location.length;
  
      List<Fix> possibleFixes = new List<Fix>();
  
      for (var sourceChange in analysisErrFix.fixes) {
        List<Edit> edits = new List<Edit>();
        for (var sourceFileEdit in sourceChange.edits) {
          for (var sourceEdit in sourceFileEdit.edits) {
            edits.add(new Edit(
                sourceEdit.offset,
                sourceEdit.length,
                sourceEdit.replacement));
          }
        }
        Fix possibleFix = new Fix(sourceChange.message, edits);
        possibleFixes.add(possibleFix);
      }
  
      return new ProblemFix(
          possibleFixes,
          problemMessage,
          problemOffset,
          problemLength);
    }
  
  }
  
  /// Set of fixes for a particular problem.
  class ProblemFix {
    final List<Fix> fixes;
    final String problemMessage;
    final int offset;
    final int length;
  
    ProblemFix(this.fixes, this.problemMessage, this.offset, this.length);
  }
  
  /// A single way of fixing a particular problem
  class Fix {
    final String message;
    final List<Edit> edits;
  