https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99680
--- Comment #2 from Vladimir Makarov <vmakarov at gcc dot gnu.org> --- Sorry for the troubles with my previous patch. I should have not be in hurry to fix PR99663. I'll fix it today. Jakub's patch could be a candidate but I prefer check constraint[0] on '\0'.
