https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64813
--- Comment #4 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Dominique d'Humieres from comment #3) > Revision r219696 is OK, r219776 gives the ICE, likely r219737. Unlikely, the only file changed by r219737 isn't even included in the failing tests, and even if it was would not define anything without -std=c++14. This is a compiler bug, not a library bug. The bug is the ICE, which is in the compiler.