[Bug c++/78446] Ambiguous member lookup for operator() in a function call expression treated as hard error in SFINAE context

[cvs-commit at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78446

--- Comment #2 from CVS Commits <cvs-commit at gcc dot gnu.org> ---
The master branch has been updated by Patrick Palka <ppa...@gcc.gnu.org>:

https://gcc.gnu.org/g:098cf31aa2631db6922d4de5661c1b0ce19af0aa

commit r11-399-g098cf31aa2631db6922d4de5661c1b0ce19af0aa
Author: Patrick Palka <ppa...@redhat.com>
Date:   Thu May 14 12:56:18 2020 -0400

    c++: Missing SFINAE with lookup_fnfields [PR78446]

    Here we're failing to do SFINAE in build_op_call when looking up the
    class's operator() via lookup_fnfields, which calls lookup_member always
    with complain=tf_warning_or_error; from there we would complain
    about an ambiguous lookup for operator().

    This patch fixes this by adding a tsubst_flags_t parameter to
    lookup_fnfields and adjusting all its callers appropriately.

    gcc/cp/ChangeLog:

            PR c++/78446
            * call.c (build_op_call): Pass complain to lookup_fnfields.
            (build_special_member_call): Likewise.
            * class.c (type_requires_array_cookie): Pass tf_warning_or_error
            to lookup_fnfields.
            * cp-tree.h (lookup_fnfields): Add tsubst_flags_t parameter.
            * except.c (build_throw): Pass tf_warning_or_error to
            lookup_fnfields.
            * init.c (build_new_1): Pass complain to lookup_fnfields.
            * method.c (locate_fn_flags): Likewise.
            * name-lookup.c (lookup_name_real_1): Pass tf_warning_or_error
            to lookup_fnfields.
            * pt.c (tsubst_baselink): Pass complain to lookup_fnfields.
            * search.c (lookup_fnfields): New 'complain' parameter.  Pass it
            to lookup_member.

    gcc/testsuite/ChangeLog:

            PR c++/78446
            * g++.dg/template/sfinae31.C: New test.