https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110739
--- Comment #6 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:3cc45681c66e7385299cb8bdb0aa5b5123a9524e commit r16-1735-g3cc45681c66e7385299cb8bdb0aa5b5123a9524e Author: Tomasz KamiÅski <tkami...@redhat.com> Date: Fri Jun 27 12:35:53 2025 +0200 libstdc++: Fix warnings introduced by type-erasing for chrono commits [PR110739] The r16-1709-g4b3cefed1a08344495fedec4982d85168bd8173f caused `-Woverflow` in empty_spec.cc file. This warning is not cause by any issue in shipping code, and results in taking to much shortcut when implementing a test-only custom representation type Rep, where long was always used to store a value. In particular common type for Rep and long long int, was de-facto long. This is addressed by adding Under template parameter, that controls the type of stored value, and handling it properly in common_type specializations. No changes to shipping code are necessary. Secondly, extracting _M_locale_fmt calls in r16-1712-gcaac94, resulted in __ctx format parameter no longer being used. This patch removes such parameter entirely, and replace _FormatContext template parameter, with _OutIter parameter for __out. For consistency type of the __out is decoupled from _FormatContext, for functions that still need context: * to extract locale (_M_A_a, _M_B_b, _M_c, _M_p, _M_r, _M_subsecs) * perform formatting for duration/subseconds (_M_Q, _M_T, _M_S, _M_subsecs) PR libstdc++/110739 libstdc++-v3/ChangeLog: * include/bits/chrono_io.h (__formatter_chrono::_M_format_to): Rename _Out to _OutIter for consistency, and update calls to specifier functions. (__formatter_chrono::_M_wi, __formatter_chrono::_M_C_y_Y) (__formatter_chrono::_M_D_x, __formatter_chrono::_M_d_e) (__formatter_chrono::_M_F, __formatter_chrono::_M_g_G) (__formatter_chrono::_M_H_I, __formatter_chrono::_M_j) (__formatter_chrono::_M_m, __formatter_chrono::_M_M) (__formatter_chrono::_M_q, __formatter_chrono::_M_R_X) (__formatter_chrono::_M_u_w, __formatter_chrono::_M_U_V_W) (__formatter_chrono::_M_z, __formatter_chrono::_M_z): Remove _FormatContext parameter, and introduce _OutIter for __out type. (__formatter_chrono::_M_a_A, __formatter_chrono::_M_B_b) (__formatter_chrono::_M_p, __formatter_chrono::_M_Q) (__formatter_chrono::_M_r, __formatter_chrono::_M_S) (__formatter_chrono::_M_subsecs, __formatter_chrono::_M_T): Introduce separate _OutIter template parameter for __out. (__formatter_chrono::_M_c, __formatter_chrono::_M_T): Likewise, and adjust calls to specifiers functions. * testsuite/std/time/format/empty_spec.cc: Make underlying type for Rep configurable.
