[Bug c++/122788] [[maybe_unused]] ignored in expansion statement

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=122788

--- Comment #4 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:cf865c811be1b83e960b3e661123cb19105d3181

commit r16-5507-gcf865c811be1b83e960b3e661123cb19105d3181
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Sat Nov 22 12:39:09 2025 +0100

    c++: Fix up [[maybe_unused]] handling on expansion stmts [PR122788]

    This PR complains that [[maybe_unused]] attribute is ignored on
    the range-for-declaration of expansion-statement.

    We copy DECL_ATTRIBUTES and apply late attributes, but early attributes
    don't have their handlers called again, so some extra flags need to be
    copied as well.
    This copies TREE_USED and DECL_READ_P flags.

    2025-11-22  Jakub Jelinek  <jakub@redhat.com>

            PR c++/122788
            * pt.cc (finish_expansion_stmt): Or in TREE_USED and DECL_READ_P
            flags from range_decl to decl or from corresponding structured
binding
            to this_decl.

            * g++.dg/cpp26/expansion-stmt27.C: New test.