https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78446
--- Comment #2 from CVS Commits ---
The master branch has been updated by Patrick Palka :
https://gcc.gnu.org/g:098cf31aa2631db6922d4de5661c1b0ce19af0aa
commit r11-399-g098cf31aa2631db6922d4de5661c1b0ce19af0aa
Author: Patrick Palka
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.
