https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94538
--- Comment #4 from Wilco <wilco at gcc dot gnu.org> --- (In reply to Zdenek Sojka from comment #3) > (In reply to Wilco from comment #2) > > This was introduced by commit e24f6408d so only in GCC10. > > Thank you for checking this! > > I am quite sure this fails in gcc-9 as well: ... > Perhaps the offending commit, or part of it, was backported to gcc-9 as well? It's possible it was recently backported and our GCC9 builds don't yet have it. But that whole patch is badly broken and introduces multiple issues...