message: fix handling of rvalue reference variant elements wrt variant get overloads
diff: @@ -420,6 +420,12 @@ namespace ranges
  {
  *t_ = std::addressof(t.get());
  }
  + template<typename U>
  + void operator()(indexed_element<U &&, N> t) const noexcept
  + {
  + U &&u = t.get();
  + *t_ = std::addressof(u);
  + }
  void operator()(indexed_element<void, N>) const noexcept
  {}
  };
  