[Bug c++/118846] [modules] Unbound template arguments considered TU-local

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=118846

--- Comment #1 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Nathaniel Shead <nshead@gcc.gnu.org>:

https://gcc.gnu.org/g:9f1f4efc06f43b1ba8c1cf5a31d5b73d6a2bb12d

commit r15-7560-g9f1f4efc06f43b1ba8c1cf5a31d5b73d6a2bb12d
Author: Nathaniel Shead <nathanieloshead@gmail.com>
Date:   Wed Feb 12 19:15:22 2025 +1100

    c++/modules: Don't treat template parameters as TU-local [PR118846]

    There are two separate issues making various template parameters behave
    as if they were TU-local.

    Firstly, the TU-local detection code uses WILDCARD_TYPE_P to check for
    types that are not yet concrete; for some reason UNBOUND_CLASS_TEMPLATE
    is not on that list.  I don't see any particular reason why it shouldn't
    be, so this patch adds it; this may solve other latent issues as well.

    Secondly, the TEMPLATE_DECL for a type with expressions involving
    TEMPLATE_TEMPLATE_PARM_Ps is currently always constrained to internal
    linkage, because the result does not have TREE_PUBLIC set. Rather than
    messing with TREE_PUBLIC here, I think rather we just should ensure that
    we only attempt to constrain visiblity of templates of type, variable,
    or function decls.

            PR c++/118846

    gcc/cp/ChangeLog:

            * cp-tree.h (WILDCARD_TYPE_P): Include UNBOUND_CLASS_TEMPLATE.
            * decl2.cc (min_vis_expr_r): Don't assume a TEMPLATE_DECL will
            be a function or variable.

    gcc/testsuite/ChangeLog:

            * g++.dg/modules/pr118846_a.C: New test.
            * g++.dg/modules/pr118846_b.C: New test.

    Signed-off-by: Nathaniel Shead <nathanieloshead@gmail.com>
    Reviewed-by: Jason Merrill <jason@redhat.com>