https://gcc.gnu.org/bugzilla/show_bug.cgi?id=69600
--- Comment #3 from sshannin at gmail dot com --- (In reply to Jonathan Wakely from comment #2) > The value_type of your map is pair<const std::string, inner_data_t> an you > can't move the first part of that pair, and you can't copy the second part > of that pair, so you can't move or copy it. I'm not sure exactly what you mean/what the value_type typedef inside the map has to do with this. Note that std::map<std::string, unique_ptr<int>> does seem to work here (where presumably value_type is pair<const string, unique_ptr<int>>). Also, I just confirmed this did previously work on gcc-4.8.2
