https://gcc.gnu.org/bugzilla/show_bug.cgi?id=59526
--- Comment #4 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Francois Dumont <fdum...@gcc.gnu.org>: https://gcc.gnu.org/g:92456291849fe88303bbcab366f41dcd4a885ad5 commit r14-3926-g92456291849fe88303bbcab366f41dcd4a885ad5 Author: François Dumont <fdum...@gcc.gnu.org> Date: Wed Aug 23 19:15:43 2023 +0200 libstdc++: [_GLIBCXX_INLINE_VERSION] Fix <format> friend declaration GCC do not consider the inline namespace in friend function declarations. This is PR c++/59526, we need to explicit this namespace. libstdc++-v3/ChangeLog: * include/std/format (std::__format::_Arg_store): Explicit version namespace on make_format_args friend declaration.