https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93467
--- 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:11c7261128ad3ee136508703b20e45cbe04f8dd0 commit r11-1243-g11c7261128ad3ee136508703b20e45cbe04f8dd0 Author: Patrick Palka <ppa...@redhat.com> Date: Thu Jun 11 16:33:41 2020 -0400 c++: constrained class template friend [PR93467] This fixes two issues in our handling of constrained class template friend declarations. The first issue is that we fail to set the constraints on the injected class template declaration during tsubst_friend_class. The second issue is that the template parameter levels within the parsed constraints of a class template friend declaration are shifted if the enclosing class is a template, and this shift leads to spurious constraint mismatch errors in associate_classtype_constraints if the friend declaration refers to an already declared class template. gcc/cp/ChangeLog: PR c++/93467 * constraint.cc (associate_classtype_constraints): If there is a discrepancy between the current template depth and the template depth of the original declaration, then adjust the template parameter depth within the current constraints appropriately. * pt.c (tsubst_friend_class): Substitute into and set the constraints on the injected declaration. gcc/testsuite/ChangeLog: PR c++/93467 * g++.dg/cpp2a/concepts-friend6.C: New test. * g++.dg/cpp2a/concepts-friend7.C: New test.
