https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100592
--- 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:d999d9b7e53b9a9cd2004a19e84c637e5e5013f5 commit r12-1183-gd999d9b7e53b9a9cd2004a19e84c637e5e5013f5 Author: Patrick Palka <ppa...@redhat.com> Date: Thu Jun 3 09:39:13 2021 -0400 c++: cv-qualified dependent name of alias tmpl [PR100592] Here, the dependent template name in the return type of f() resolves to an alias of int& after substitution, and we end up complaining about qualifying this reference type with 'const' from cp_build_qualified_type rather than just silently dropping the qualification as per [dcl.ref]/1. The problem is ultimately that make_typename_type ignores the tf_keep_type_decl flag when the dependent name is a template-id. This in turn causes the TYPE_DECL check within tsubst <case TYPENAME_TYPE> to fail, and so we end up not passing tf_ignore_bad_quals to cp_build_qualified_type. This patch fixes this by making make_typename_type respect the tf_keep_type_decl flag in this situation. PR c++/100592 gcc/cp/ChangeLog: * decl.c (make_typename_type): After calling lookup_template_class, adjust the result to its TYPE_NAME and then consider the tf_keep_type_decl flag. gcc/testsuite/ChangeLog: * g++.dg/cpp0x/alias-decl-71.C: New test.
