anchor.diff:          findProcedure(coreLibrary, 'print'),
           findFactoryConstructor(completerClass, 'sync'),
           findConstructor(syncIterableClass, ''),
  +        findConstructor(streamIteratorClass , ''),
           findFactoryConstructor(futureClass, 'microtask'),
           findConstructor(streamControllerClass, ''),
           findProcedure(asyncLibrary, '_asyncThenWrapperHelper'),
  
positive.code: 
      var completerClass = findClass(asyncLibrary, 'Completer');
      var futureClass = findClass(asyncLibrary, 'Future');
      var syncIterableClass = findClass(coreLibrary, '_SyncIterable');
      var streamControllerClass = findClass(
          asyncLibrary, '_AsyncStarStreamController');
  
negative.code:       this.printProcedure,
        this.completerConstructor,
        this.syncIterableConstructor,
        this.streamIteratorConstructor,
        this.futureMicrotaskConstructor,
        this.streamControllerConstructor,
        this.asyncThenWrapper,
  