anchor.diff:      if (info.isConst) {
         result['const'] = true;
         if (info.initializer != null) {
  -        result['initializer'] = idFor(info.initializer).serializedId;
  +        result['initializer'] = idFor(info.initializer!).serializedId;
         }
       }
       return result;
  
positive.code:   }
  
    OutputUnitInfo parseOutputUnit(Map json) {
      OutputUnitInfo result = parseId(json['id']);
      result
        ..filename = json['filename']
        ..name = json['name']
        ..size = json['size'];
      result.imports
          .addAll((json['imports'] as List).map((s) => s as String) ?? const []);
      return result;
    }
  
    LibraryInfo parseLibrary(Map json) {
      LibraryInfo result = parseId(json['id']);
      result
        ..name = json['name']
        ..uri = Uri.parse(json['canonicalUri'])
        ..outputUnit = parseId(json['outputUnit'])
        ..size = json['size'];
      for (var child in json['children'].map(parseId)) {
        if (child is FunctionInfo) {
          result.topLevelFunctions.add(child);
        } else if (child is FieldInfo) {
  
negative.code:   }
  
    ClassTypeInfo parseClassType(Map json) {
      final result = parseId(json['id']) as ClassTypeInfo;
      result
        ..name = json['name']
        ..parent = parseId(json['parent'])
        ..outputUnit = parseId(json['outputUnit']) as OutputUnitInfo?
        ..size = json['size'];
      return result;
    }
  
    FieldInfo parseField(Map json) {
      final result = parseId(json['id']) as FieldInfo;
      return result
        ..name = json['name']
        ..parent = parseId(json['parent'])
        ..coverageId = json['coverageId']
        ..outputUnit = parseId(json['outputUnit']) as OutputUnitInfo?
        ..size = json['size']
        ..type = json['type']
        ..inferredType = json['inferredType']
        ..code = parseCode(json['code'])
        ..isConst = json['const'] ?? false
        ..initializer = parseId(json['initializer']) as ConstantInfo?
        ..closures = (json['children'] as List)
            .map<ClosureInfo>((c) => parseId(c) as ClosureInfo)
            .toList();
    }
  
    ConstantInfo parseConstant(Map json) {
      final result = parseId(json['id']) as ConstantInfo;
      return result
        ..name = json['name']
        ..code = parseCode(json['code'])
        ..size = json['size']
        ..outputUnit = parseId(json['outputUnit']) as OutputUnitInfo?;
    }
  
    TypedefInfo parseTypedef(Map json) {
      final result = parseId(json['id']) as TypedefInfo;
      return result
        ..name = json['name']
        ..parent = parseId(json['parent'])
  