https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94645
--- Comment #11 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:f9f166251f181ddcee64092d89aecbc1166ca706 commit r10-7932-gf9f166251f181ddcee64092d89aecbc1166ca706 Author: Patrick Palka <ppa...@redhat.com> Date: Thu Apr 23 17:29:55 2020 -0400 c++: Lambda in friend of constrained class [PR94645] In the testcase below, when grokfndecl processes the operator() decl for the lambda inside the friend function foo, processing_template_decl is rightly 1, but template_class_depth on the lambda's closure type incorrectly returns 0 instead of 1. Since processing_template_decl > template_class_depth, this makes grokfndecl think that the operator() has its own set of template arguments, and so we attach the innermost set of constraints -- those belonging to struct l -- to the operator() decl. We then get confused when checking constraints_satisfied_p on the operator() because it doesn't have template information and yet has constraints associated with it. This patch fixes template_class_depth to return the correct template nesting level in cases like these, in that when it hits a friend function it walks into the DECL_FRIEND_CONTEXT of the friend rather than into the CP_DECL_CONTEXT. gcc/cp/ChangeLog: PR c++/94645 * pt.c (template_class_depth): Walk into the DECL_FRIEND_CONTEXT of a friend declaration rather than into its CP_DECL_CONTEXT. gcc/testsuite/ChangeLog: PR c++/94645 * g++.dg/cpp2a/concepts-lambda6.C: New test.
