std::unique_ptr WithTags()

in spectator/id.h [107:111]

• 5 lines of code
• 2 McCabe index (conditional complexity)

  std::unique_ptr<Id> WithTags(Tags&& extra_tags) const {
    Tags tags{GetTags()};
    tags.move_all(std::move(extra_tags));
    return std::make_unique<Id>(Name(), tags);
  }