anchor.diff:    Future<List<Assist>> compute() async {
       // TODO(brianwilkerson) Determine whether this await is necessary.
       await null;
  -    if (!setupCompute()) {
  +    if (!_setupCompute()) {
         return assists;
       }
   
  
positive.code:   }
  
    Future<List<Assist>> computeAssist(AssistKind assistKind) async {
      if (!setupCompute()) {
        return assists;
      }
  
  
negative.code:     return utils.getRangeText(range);
    }
  
    bool _setupCompute() {
      try {
        utils = new CorrectionUtils(unit);
      } catch (e) {
        throw new CancelCorrectionException(exception: e);
      }
  
      node = new NodeLocator(selectionOffset, selectionEnd).searchWithin(unit);
      return node != null;
    }
  
    Future<void> _swapParentAndChild(InstanceCreationExpression parent,
        InstanceCreationExpression child, AssistKind kind) async {
      // TODO(brianwilkerson) Determine whether this await is necessary.
  