anchor.diff:  
   /// Analyzes set of libraries by getting a mirror system and triggers the
   /// documentation of the libraries.
  -Future<MirrorSystem> getMirrorSystem(List<String> libraries,
  +Future<MirrorSystem> getMirrorSystem(List<Uri> libraries,
       {String packageRoot, bool parseSdk: false}) {
     if (libraries.isEmpty) throw new StateError('No Libraries.');
     // Finds the root of SDK library based off the location of docgen.
  
positive.code:   return contents;
  }
  
  List<String> _listLibraries(List<String> args) {
    var libraries = new List<String>();
    for (var arg in args) {
      var type = FileSystemEntity.typeSync(arg);
  
      if (type == FileSystemEntityType.FILE) {
        if (arg.endsWith('.dart')) {
          libraries.add(path.absolute(arg));
          logger.info('Added to libraries: ${libraries.last}');
        }
      } else {
  
negative.code:       _coreLibrary = _sdkLibraries.singleWhere((lib) =>
            lib.uri.toString().startsWith('dart:core'));
        var availableLibrariesByPath = new Map.fromIterables(
            availableLibraries.map((each) => each.uri),
            availableLibraries);
        var librariesToDocument = requestedLibraries.map(
            (each) => availableLibrariesByPath.putIfAbsent(each,
  