http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44436
--- Comment #21 from Kira Backes <Kira.Backes at NRWsoft dot de> 2011-06-09 12:21:07 UTC --- Hi, I don't mean a pair of unique_ptr, just any combination with a unique_ptr. I for example very often need: std::map<uint32_t, unique_ptr<User>> instancesByIds_; Now if I want to insert a User, with a shared_ptr I'd have to do: instancesByIds_[id] = user; Now with a unique_ptr I'd like to do the same: instancesByIds_[id] = user; instancesByIds_[id] = std::move(user); Both doesnt work. Emplace is the practical solution (please correct me if there's a better way): instancesByIds_.emplace(id, std::move(user)); rgds, Kira