anchor.diff:  import 'dart:mirrors';
   import 'dart:io';
   import 'package:path/path.dart' as path;
  -
   
   Future<String> httpGet(String url) {
     HttpClient client = new HttpClient();
  
positive.code:   }).toList();
  }
  
  
  /// Takes a list of paths and if an element is a directory it expands it to
  /// the Dart source files contained by this directory, otherwise the element is
  /// added to the result unchanged.
  
negative.code:     if (directory.existsSync()) {
        for (var entry
            in directory.listSync(recursive: true, followLinks: false)) {
          var relative = path.relative(entry.path, from: directory.path);
          if (_isDartFileName(entry.path) && !_isInHiddenDir(relative)) {
            files.add(entry.path);
          }
        }
  