anchor.diff:    final generated = generator(ruleName, toClassName(ruleName));
     if (outDir != null) {
       final outPath = '$outDir/$stubPath/$ruleName.dart';
  -    final outFile = new File(outPath);
  +    final outFile = File(outPath);
       if (outFile.existsSync()) {
         print('Warning: stub already exists at $outPath; skipping');
         return;
  
positive.code:   final outDir = options['out'];
  
    if (outDir != null) {
      final d = new Directory(outDir);
      if (!d.existsSync()) {
        print("Directory '${d.path}' does not exist");
        return;
  
negative.code: /// Generates rule and rule test stub files (into `src/rules` and `test/rules`
  /// respectively), as well as the rule index (`rules.dart`).
  void main([List<String> args]) {
    final parser = ArgParser(allowTrailingOptions: true)
      ..addOption('out', abbr: 'o', help: 'Specifies project root.')
      ..addOption('name',
          abbr: 'n', help: 'Specifies lower_underscore rule name.');
  