[Bug c++/93083] [C++20] copy deduction rejected when doing CTAD for NTTP

[cvs-commit at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93083

--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-10 branch has been updated by Jason Merrill
<ja...@gcc.gnu.org>:

https://gcc.gnu.org/g:e6e42891d80c12c4fac36d6273b8d4e31a3d0a2a

commit r10-9133-ge6e42891d80c12c4fac36d6273b8d4e31a3d0a2a
Author: Jason Merrill <ja...@redhat.com>
Date:   Wed Nov 25 17:05:24 2020 -0500

    c++: Fix deduction from auto template parameter [PR93083]

    The check in do_class_deduction to handle passing one class placeholder
    template parm as an argument for itself needed to be extended to also
handle
    equivalent parms from other templates.

    gcc/cp/ChangeLog:

            PR c++/93083
            * pt.c (convert_template_argument): Handle equivalent placeholders.
            (do_class_deduction): Look through EXPR_PACK_EXPANSION, too.

    gcc/testsuite/ChangeLog:

            PR c++/93083
            * g++.dg/cpp2a/nontype-class40.C: New test.