https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65923
--- Comment #5 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Richard Geary from comment #2) > This is still present in g++ 5.3.0, and also affects > std::literals::string_literals. The flag -Wno-literal-suffix does not turn > it off. It does for GCC 7+, that was PR 69523 (which looks like a transposition of this bug number, but isn't).