https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109162
--- Comment #9 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Tomasz Kaminski <tkami...@gcc.gnu.org>: https://gcc.gnu.org/g:84d668b0ca67c5d3fe6430f101d61e60aa796a81 commit r15-9198-g84d668b0ca67c5d3fe6430f101d61e60aa796a81 Author: Tomasz KamiÅski <tkami...@redhat.com> Date: Thu Apr 3 17:22:39 2025 +0200 libstdc++: Provide formatter for vector<bool>::reference [PR109162] This patch implement formatter for vector<bool>::reference which is part of P2286R8. To indicate partial support we define __glibcxx_format_ranges macro value 1, without defining __cpp_lib_format_ranges. To avoid including the whole content of the <format> header, we introduce new bits/formatfwd.h forward declares classes required for newly introduce formatter. The signatures of the user-facing parse and format method of the provided formatters deviate from the standard by constraining types of params: * _Bit_reference instead T satisfying is-vector-bool-reference<T> * _CharT is constrained __formatter::__char * basic_format_parse_context<_CharT> for parse argument * basic_format_context<_Out, _CharT> for format second argument The standard specifies last three of above as unconstrained types, which leads to formattable<vector<bool>::reference, char32_t> (and any other type as char) being true. PR libstdc++/109162 libstdc++-v3/ChangeLog: * include/Makefile.am: Add bits/formatfwd.h. * include/Makefile.in: Add bits/formatfwd.h. * include/bits/version.def: Define __glibcxx_format_ranges without corresponding std name. * include/bits/version.h: Regenerate. * include/std/format (basic_format_context, __format::__char): Move declartions to bits/formatfwd.h. (formatter<_Tp, _CharT>): Remove default argument for _CharT parameter, now specified in forward declaration in bits/formatfwd.h. * include/std/vector (formatter<_Bit_reference, _CharT>): Define. * include/bits/formatfwd.h: New file with forward declarations for bits of std/format. * testsuite/23_containers/vector/bool/format.cc: New test. Reviewed-by: Jonathan Wakely <jwak...@redhat.com> Signed-off-by: Tomasz KamiÅski <tkami...@redhat.com>
