https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120644
Giuseppe D'Angelo <peppe at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Ever confirmed|0 |1 Last reconfirmed| |2025-06-13 Status|UNCONFIRMED |NEW --- Comment #3 from Giuseppe D'Angelo <peppe at gcc dot gnu.org> --- Hi, Confirmed. I can easily push the workaround that you mentioned: diff --git a/libstdc++-v3/include/std/optional b/libstdc++-v3/include/std/optional index 2ae71f11e21..cc7af5bbd7d 100644 --- a/libstdc++-v3/include/std/optional +++ b/libstdc++-v3/include/std/optional @@ -1815,7 +1815,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION ranges::enable_view<optional<_Tp>> = true; template<typename _Tp> - inline constexpr auto + inline constexpr range_format format_kind<optional<_Tp>> = range_format::disabled; #endif // __cpp_lib_optional_range_support Which seems to fix the xtreme-header-2_b.C (... to 7, 8 looks like it's failing in something unrelated). But this seems to be fixing a symptom, not a cause, as the code is otherwise completely equivalent? Should I go ahead nonetheless to cleanup these new test failures?