[Bug c++/123977] [16 Regression] ICE on member function pointer in C++26 since r16-4338

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=123977

--- Comment #6 from GCC Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Jakub Jelinek <jakub@gcc.gnu.org>:

https://gcc.gnu.org/g:5f75fc37b131c701a5b5c627239fa4e4dfabe230

commit r16-7358-g5f75fc37b131c701a5b5c627239fa4e4dfabe230
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Fri Feb 6 11:27:52 2026 +0100

    tree: Fix up build_function_type for (...) fntypes [PR123977]

    The following testcase ICEs in -std=c++26 mode since my r16-4338 C++26
    va_start changes.
    The problem is that if we have anything non-canonical in a function
    type with (...) in C++26 (or C23/C2Y) mode, in this case the R typedef
    on return type rather than void, then we try to build TYPE_CANONICAL
    for that, but weren't passing in the no_named_args_stdarg_p, so
    a type with TYPE_NO_NAMED_ARGS_STDARG_P flag set got TYPE_CANONICAL
    with TYPE_NO_NAMED_ARGS_STDARG_P flag cleared and comptypes then
    didn't like that as those aren't really compatible types
    (...) vs. the C89-ish () which even C++ uses for some type-generic
    etc. builtins.

    2026-02-05  Jakub Jelinek  <jakub@redhat.com>

            PR c++/123977
            * tree.cc (build_function_type): Pass no_named_args_stdarg_p
            as last argument to recursive call.

            * g++.dg/cpp26/stdarg10.C: New test.