https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94549
--- Comment #3 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:0e665f256b4ac8c5f78713ebd4e9378fd4ecf5a8 commit r10-7859-g0e665f256b4ac8c5f78713ebd4e9378fd4ecf5a8 Author: Patrick Palka <ppa...@redhat.com> Date: Tue Apr 21 18:41:02 2020 -0400 c++: Constrained inherited constructor template [PR94549] A comment in satisfy_declaration_constraints says /* For inherited constructors, consider the original declaration; it has the correct template information attached. */ d = strip_inheriting_ctors (d); but it looks like this comment is wrong when the inherited constructor is for an instantiation of a constructor template. In that case, DECL_TEMPLATE_INFO is correct and DECL_INHERITED_CTOR points to the constructor template of the base class rather than to the particular instantiation of the constructor template (and so the DECL_TI_ARGS of the DECL_INHERITED_CTOR are in their dependent form). So doing strip_inheriting_ctors in this case then eventually leads to satisfy_associated_constraints returning true regardless of the constraints themselves, due to the passed in 'args' being dependent. An inherited constructor seems to have a non-empty DECL_TEMPLATE_INFO only when it's for an instantiation of a constructor template, so this patch fixes this issue by checking for empty DECL_TEMPLATE_INFO before calling strip_inheriting_ctors. There is another unguarded call to strip_inheriting_ctors in get_normalized_constraints_from_decl, but this one seems to be safe to do unconditionally because the rest of that function doesn't need/look at the DECL_TI_ARGS of the decl. gcc/cp/ChangeLog: PR c++/94549 * constraint.cc (satisfy_declaration_constraints): Don't strip the inherited constructor if it already has template information. gcc/testsuite/ChangeLog: PR c++/94549 * g++.dg/concepts/inherit-ctor3.C: Adjust expected diagnostics. * g++.dg/cpp2a/concepts-inherit-ctor4.C: New test. * g++.dg/cpp2a/concepts-inherit-ctor8.C: New test.
