message: Fixed wrong base branch.
diff: @@ -796,7 +796,7 @@ class Builder {
  // add without a tag
  template <typename T>
  uint8_t* addInternal(T const& sub) {
  - if (_stack.empty()) {
  + if (_stack.empty() || std::is_same<T, Serializable>::value) {
  return set(sub);
  }
  