  void initialize_definition_ids() const {
    std::call_once(definition_ids_init_, [&]() {
      AssignIDToDefinition vis;
      holder_->accept(vis);
      if (whitespaceOpe) { whitespaceOpe->accept(vis); }
      if (wordOpe) { wordOpe->accept(vis); }
      definition_ids_.swap(vis.ids);
    });
  }
Unknown