https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115801
--- Comment #5 from GCC Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Nathaniel Shead <nsh...@gcc.gnu.org>: https://gcc.gnu.org/g:79209273663672ff05663554741fd2558b4aac99 commit r15-2808-g79209273663672ff05663554741fd2558b4aac99 Author: Nathaniel Shead <nathanielosh...@gmail.com> Date: Tue Aug 6 15:41:38 2024 +1000 c++/modules: Handle instantiating already tsubsted template friend classes [PR115801] With modules it may be the case that a template friend class provided with a qualified name is not found by name lookup at instantiation time, due to the class not being exported from its module. This causes issues in tsubst_friend_class which did not handle this case. This is caused by the named friend class not actually requiring tsubsting. This was already worked around for the "found by name lookup" case (g++.dg/template/friend5.C), but it looks like there's no need to do name lookup at all for this particular case to work. We do need to be careful to continue to do name lookup to handle templates from an outer current instantiation though; this patch adds a new testcase for this as well. This should not impact modules (because exportingness will only affect namespace lookup). PR c++/115801 gcc/cp/ChangeLog: * pt.cc (tsubst_friend_class): Return the type immediately when no tsubsting or name lookup is required. gcc/testsuite/ChangeLog: * g++.dg/modules/tpl-friend-16_a.C: New test. * g++.dg/modules/tpl-friend-16_b.C: New test. * g++.dg/template/friend82.C: New test. Signed-off-by: Nathaniel Shead <nathanielosh...@gmail.com> Reviewed-by: Patrick Palka <ppa...@redhat.com> Reviewed-by: Jason Merrill <ja...@redhat.com>
