anchor.diff:    }
   
     LibraryInfo parseLibrary(Map json) {
  -    var result = parseId(json['id'])
  -        ..name = json['name']
  +    LibraryInfo result = parseId(json['id']);
  +    result..name = json['name']
           ..uri = Uri.parse(json['canonicalUri'])
           ..outputUnit = parseId(json['outputUnit'])
           ..size = json['size'];
  -    assert(result is LibraryInfo);
       for (var child in json['children'].map(parseId)) {
         if (child is FunctionInfo) {
           result.topLevelFunctions.add(child);
  
positive.code:   }
  
    ClassInfo parseClass(Map json) {
      var result = parseId(json['id'])
          ..name = json['name']
          ..outputUnit = parseId(json['outputUnit'])
          ..size = json['size']
          ..isAbstract = json['modifiers']['abstract'] == true;
  
negative.code:   }
  
    FieldInfo parseField(Map json) {
      FieldInfo result = parseId(json['id']);
      return result..name = json['name']
        ..outputUnit = parseId(json['outputUnit'])
        ..size = json['size']
        ..type = json['type']
  