public void addChild(NodeDescriptor parent, NodeDescriptor child) {
    List<NodeDescriptor> children;

    if (parent == null) {
      children = myRootChildren;
    }
    else {
      children = myChildrenMap.computeIfAbsent(parent, c -> new ArrayList<>());
    }
    children.add(child);
    if (myInitial && child instanceof LocalVariableDescriptorImpl) {
      ((LocalVariableDescriptorImpl)child).setNewLocal(false);
    }
  }
public void addChild(NodeDescriptor parent, NodeDescriptor child)