https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105758
--- 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:4f84f12066953186cce4328b7f178d3daa2fe96e commit r13-871-g4f84f12066953186cce4328b7f178d3daa2fe96e Author: Patrick Palka <ppa...@redhat.com> Date: Tue May 31 16:49:08 2022 -0400 c++: non-dep call with empty TYPE_BINFO [PR105758] Here the out-of-line definition of Z<T>::z causes duplicate_decls to change z's type from using the primary template type Z<T> (which is also the type of the injected class name) to the implicit instantiation Z<T>, and this latter type lacks a TYPE_BINFO (although its TYPE_CANONICAL was set by a special case in lookup_template_class to point to the former). Later, when processing the non-dependent call z->foo(0), build_over_call relies on the object argument's TYPE_BINFO to build the templated form for this call, which fails because the object argument type has empty TYPE_BINFO due to the above. It seems weird that the implicit instantiation Z<T> doesn't have the same TYPE_BINFO as the primary template type Z<T>, despite them being proclaimed equivalent via TYPE_CANONICAL. So I tried also setting TYPE_BINFO in the special case in lookup_template_class, but that led to some problems with constrained partial specializations of the form Z<T>. I'm not sure what, if anything, we ought to do about the subtle differences between these two versions of the same type. Fortunately it seems we don't need to rely on TYPE_BINFO at all in build_over_call here -- the z_candidate struct already contains the exact binfos we need to rebuild the BASELINK for the templated form. PR c++/105758 gcc/cp/ChangeLog: * call.cc (build_over_call): Use z_candidate::conversion_path and ::access_path instead of TYPE_BINFO when building the BASELINK for the templated form. gcc/testsuite/ChangeLog: * g++.dg/template/non-dependent24.C: New test.
