https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94799
--- Comment #7 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Marek Polacek <mpola...@gcc.gnu.org>: https://gcc.gnu.org/g:ef3479afc5ab415f00a53fc6f6a990df7f6a0747 commit r11-86-gef3479afc5ab415f00a53fc6f6a990df7f6a0747 Author: Marek Polacek <pola...@redhat.com> Date: Tue Apr 28 22:30:44 2020 -0400 c++: Member template function lookup failure [PR94799] Whew, this took a while. We fail to parse "p->template A<T>::a()" (where p is of type A<T> *) because since r249752 we treat the RHS of the -> as dependent and avoid a lookup in the enclosing context: since that rev cp_parser_template_name checks parser->context->object_type too, which here is unknown_type_node, signalling a type-dependent object: 7756 if (dependent_p) 7757 /* Tell cp_parser_lookup_name that there was an object, even though it's 7758 type-dependent. */ 7759 parser->context->object_type = unknown_type_node; with which cp_parser_template_name returns identifier 'A', cp_parser_class_name then creates a TEMPLATE_ID_EXPR A<T>, but then 23735 decl = make_typename_type (scope, decl, tag_type, tf_error); in cp_parser_class_name fails because scope is NULL. Then we return error_mark_node and parse errors ensue. I've tried various approaches, e.g. keeping TEMPLATE_ID_EXPR around instead of calling make_typename_type, which didn't work, whereupon I realized that since we don't want to perform name lookup if we've seen the template keyword and the scope is dependent, we can adjust parser->context->object_type and use the type of the object expression as the scope, even if it's type-dependent. This should be in line with [basic.lookup.classref]p4. If the postfix expression doesn't have a type, use typeof to carry its type. This typeof will be processed in tsubst/TYPENAME_TYPE. PR c++/94799 * parser.c (cp_parser_postfix_dot_deref_expression): If we have a type-dependent object of class type, stash it to parser->context->object_type. If the postfix expression doesn't have a type, use typeof. (cp_parser_class_name): Consider object scope too. (cp_parser_lookup_name): Remove code dealing with the case when object_type is unknown_type_node. * g++.dg/lookup/this1.C: Adjust dg-error. * g++.dg/template/lookup12.C: New test. * g++.dg/template/lookup13.C: New test. * g++.dg/template/lookup14.C: New test. * g++.dg/template/lookup15.C: New test.
