https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79118
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Ah, g++ 6 ICEs with -Wall.
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=79118
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Ah, g++ 6 ICEs with -Wall.