[Bug libstdc++/122022] bind_front/bind_back/not_fn pass function parameters by value

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122022

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Tomasz Kaminski <tkaminsk@gcc.gnu.org>:

https://gcc.gnu.org/g:f27b8040ec8f2273cffbce7b66e94c323c53c32c

commit r16-4601-gf27b8040ec8f2273cffbce7b66e94c323c53c32c
Author: Tomasz KamiÅski <tkaminsk@redhat.com>
Date:   Fri Oct 24 09:37:13 2025 +0200

    libstdc++: Forward arguments for bind_front<f>,bind_back<f>,nttp<f>
[PR122022]

    This patch fixes a missing forwarding-reference (&&) in
_Bind_fn_t::operator()
    and lambda returned from not_fn<f>.

    The bind_front<f>/bind_back<f> tests were updated to use a structure
similar
    to r16-3398-g250dd5b5604fbc to cover cases involving zero, one, and many
bound
    arguments.

            PR libstdc++/122022

    libstdc++-v3/ChangeLog:

            * include/std/functional (_Bind_fn_t): Use forwarding reference as
            paremeter.
            (std::not_fn<f>): Use forwarding reference as lambda parameter.
            * testsuite/20_util/function_objects/bind_back/nttp.cc: Rework
tests.
            * testsuite/20_util/function_objects/bind_front/nttp.cc: Likewise.
            * testsuite/20_util/function_objects/not_fn/nttp.cc: Add test for
            argument forwarding.