anchor.diff:    @override
     Future<int> runInProject() async {
       return argResults['watch'] ? _analyzeWatch() : _analyzeOnce();
  +  }
  +
  +  List<String> flutterRootComponents;
  +  bool isFlutterLibrary(String filename) {
  +    flutterRootComponents ??= path.normalize(path.absolute(ArtifactStore.flutterRoot)).split(path.separator);
  +    List<String> filenameComponents = path.normalize(path.absolute(filename)).split(path.separator);
  +    if (filenameComponents.length < flutterRootComponents.length + 4) // the 4: 'packages', package_name, 'lib', file_name
  +      return false;
  +    for (int index = 0; index < flutterRootComponents.length; index += 1) {
  +      if (flutterRootComponents[index] != filenameComponents[index])
  +        return false;
  +    }
  +    if (filenameComponents[flutterRootComponents.length] != 'packages')
  +      return false;
  +    if (filenameComponents[flutterRootComponents.length + 1] == 'flutter_tools')
  +      return false;
  +    if (filenameComponents[flutterRootComponents.length + 2] != 'lib')
  +      return false;
  +    return true;
     }
   
     Future<int> _analyzeOnce() async {
  
positive.code:             colNumber = 1;
            }
            bool shouldIgnore = false;
            if (filename == mainFile.path) {
              Match libs = conflictingNamesPattern.firstMatch(errorMessage);
              Match missing = missingFilePattern.firstMatch(errorMessage);
              if (libs != null) {
  
negative.code:     RegExp constructorTearOffsPattern = new RegExp('.+#.+// analyzer doesn\'t like constructor tear-offs');
      RegExp conflictingNamesPattern = new RegExp('^The imported libraries \'([^\']+)\' and \'([^\']+)\' cannot have the same name \'([^\']+)\'\$');
      RegExp missingFilePattern = new RegExp('^Target of URI does not exist: \'([^\')]+)\'\$');
      RegExp documentAllMembersPattern = new RegExp('^Document all public memm?bers\$');
  
      Set<String> changedFiles = new Set<String>(); // files about which we've complained that they changed
  
  