https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78488
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> --- clang version 4.0.0 (trunk 291659) accepts this with -std=c++1z as well as -std=c++14 and -std=c++11.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78488
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> --- clang version 4.0.0 (trunk 291659) accepts this with -std=c++1z as well as -std=c++14 and -std=c++11.