https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120644
--- Comment #11 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The trunk branch has been updated by Giuseppe D'Angelo <pe...@gcc.gnu.org>: https://gcc.gnu.org/g:f6f4efdf397269793167fb1303967e7ad0e467a7 commit r16-1501-gf6f4efdf397269793167fb1303967e7ad0e467a7 Author: Giuseppe D'Angelo <giuseppe.dang...@kdab.com> Date: Fri Jun 13 11:38:23 2025 +0200 libstdc++: add a workaround for format_kind<optional<T>> [PR120644] The specialization of format_kind for optional is causing a problem when optional is imported and included. The comments on the PR strongly suggest that this is a frontend bug; this commit just works around the issue by specifying the type of format_kind<optional<T>> to be `range_format`, rather than leaving the compiler deduce it via `auto`. PR c++/120644 libstdc++-v3/ChangeLog: * include/std/optional (format_kind): Do not use `auto`.
