https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65291
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Manuel López-Ibáñez from comment #3) > BTW, clang rejects the 'using': > > 10 : error: using declaration cannot refer to a constructor You need to compile as C++11.
