[Bug libstdc++/126800] Heterogeneous insertion into unordered_map doesn't work.

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126800

--- Comment #2 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Nathan Myers <ncm@gcc.gnu.org>:

https://gcc.gnu.org/g:54f01c74b1b43836d72c3ba8244fd1e679f3b3b3

commit r17-3903-g54f01c74b1b43836d72c3ba8244fd1e679f3b3b3
Author: Nathan Myers <ncm@cantrip.org>
Date:   Wed Sep 2 09:43:15 2026 -0400

    libstdc++: fix unordered_map heterogeneous insertion copying [PR126800]

    PR126800 reports that heterogeneous insertions fail to avoid
    copying the key when no insertion occurs. They call an existing
    member try_emplace that had invoked the wrong helper for their
    new usage case, and tests failed to detect the error. This patch
    calls the correct helper, and amends tests for heterogeneous
    insert operations op[], at(), try_emplace(), and
    insert_or_replace().

    libstdc++-v3/Changelog:
            PR libstdc++/126800
            * include/bits/hashtable.h: (try_emplace): Call correct helper.
            * testsuite/23_containers/unordered_map/modifiers/hetero/insert.cc:
            Check whether key arguments have been copied.