https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110358
--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> --- Patch for [[gnu::non_owning]] posted: https://gcc.gnu.org/pipermail/gcc-patches/2024-January/643998.html Not sure how important it is to accept the optional argument.
