anchor.diff:          ?.toList(),
       json['fitness'] == null
           ? null
  -        : new Fitness.fromJson(json['fitness'] as Map<dynamic, dynamic>),
  +        : new Fitness.fromJson(json['fitness'] as Map),
       json['maintenance'] == null
           ? null
           : new Maintenance.fromJson(json['maintenance'] as Map<String, dynamic>),
  
positive.code:         ? null
          : new PkgResolution.fromJson(
              json['pkgResolution'] as Map<String, dynamic>),
      json['dartFiles'] == null
          ? null
          : new Map<String, DartFileSummary>.fromIterables(
              (json['dartFiles'] as Map<String, dynamic>).keys,
              (json['dartFiles'] as Map).values.map((e) => e == null
                  ? null
                  : new DartFileSummary.fromJson(e as Map<String, dynamic>))),
      json['platform'] == null
          ? null
          : new DartPlatform.fromJson(json['platform'] as Map<String, dynamic>),
  
negative.code:     writeNotNull('components', components);
      writeNotNull(
          'uses',
          uses?.map((k, e) =>
              new MapEntry(k, e == null ? null : e.toString().split('.')[1])));
      writeNotNull('reason', reason);
      return val;
    }
  