[Bug c++/114795] internal compiler error: in finish_member_declaration after module import in gcc 14.0.1 snapshot

["cvs-commit at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114795

--- Comment #8 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:4f9401d1a802325e5dfa2db841945e1a9c59a980

commit r14-10096-g4f9401d1a802325e5dfa2db841945e1a9c59a980
Author: Patrick Palka <ppalka@redhat.com>
Date:   Tue Apr 23 14:01:22 2024 -0400

    c++/modules: deduced return type merging [PR114795]

    When merging an imported function template specialization with an
    existing one, if the existing one has an undeduced return type and the
    imported one's is already deduced, we need to propagate the deduced type
    since once we install the imported definition we won't get a chance to
    deduce it by normal means.

    So this patch makes is_matching_decl propagate the deduced return
    type alongside our propagation of the exception specification.
    Another option would be to propagate it later when installing the
    imported definition from read_function_def, but it seems preferable
    to do it sooner rather than later.

            PR c++/114795

    gcc/cp/ChangeLog:

            * module.cc (trees_in::is_matching_decl): Propagate deduced
            function return type.

    gcc/testsuite/ChangeLog:

            * g++.dg/modules/auto-4_a.H: New test.
            * g++.dg/modules/auto-4_b.C: New test.

    Reviewed-by: Jason Merrill <jason@redhat.com>