[Bug c++/102547] [11 Regression] g++ 11. ICE with NTTPs and partial specialization

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102547

--- Comment #8 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The releases/gcc-11 branch has been updated by Patrick Palka
<ppalka@gcc.gnu.org>:

https://gcc.gnu.org/g:1aef951f1aa0b50a8da12f6fe6e80f3fdaa4d98e

commit r11-9086-g1aef951f1aa0b50a8da12f6fe6e80f3fdaa4d98e
Author: Patrick Palka <ppalka@redhat.com>
Date:   Tue Oct 5 15:35:21 2021 -0400

    c++: unifying equal NONTYPE_ARGUMENT_PACKs [PR102547]

    Here during partial ordering of the two partial specializations we end
    up in unify with parm=arg=NONTYPE_ARGUMENT_PACK<V0, V1>, and crash shortly
    thereafter because uses_template_parms(parms) calls potential_const_expr
    which doesn't handle NONTYPE_ARGUMENT_PACK.

    This patch fixes this by extending potential_constant_expression to handle
    NONTYPE_ARGUMENT_PACK appropriately.

            PR c++/102547

    gcc/cp/ChangeLog:

            * constexpr.c (potential_constant_expression_1): Handle
            NONTYPE_ARGUMENT_PACK.

    gcc/testsuite/ChangeLog:

            * g++.dg/cpp0x/variadic-partial2.C: New test.
            * g++.dg/cpp0x/variadic-partial2a.C: New test.

    (cherry picked from commit d4c470c376b4cb82c9a0b7e8a4b88c44d5e4289d)