[Bug c++/115194] [modules] "reference to <symbol> is ambiguous" when multiple paths to same symbol exist through module

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115194

--- Comment #1 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The trunk branch has been updated by Jason Merrill <jason@gcc.gnu.org>:

https://gcc.gnu.org/g:8878fecc251762bc32c24e659695557797e03fd9

commit r15-1296-g8878fecc251762bc32c24e659695557797e03fd9
Author: Jason Merrill <jason@redhat.com>
Date:   Wed Jun 12 21:44:10 2024 -0400

    c++/modules: multiple usings of the same decl [PR115194]

    add_binding_entity creates an OVERLOAD to represent a using-declaration in
    module purview of a declaration in the global module, even for
    non-functions, and we were failing to merge that with the original
    declaration in name lookup.

    It's not clear to me that building the OVERLOAD is what should be
happening,
    but let's work around it for now pending an overhaul of using-decl handling
    for c++/114683.

            PR c++/115194

    gcc/cp/ChangeLog:

            * name-lookup.cc (name_lookup::process_module_binding): Strip an
            OVERLOAD from a non-function.

    gcc/testsuite/ChangeLog:

            * g++.dg/modules/using-23_a.C: New test.
            * g++.dg/modules/using-23_b.C: New test.