c++: constrained partial spec using qualified name [PR92944, PR103678]
In the nested_name_specifier branch within cp_parser_class_head, we need
to update 'type' with the result of maybe_process_partial_specialization
like we do in the template_id_p branch.
PR c++/92944
PR c++/103678
gcc/cp/ChangeLog:
* parser.cc (cp_parser_class_head): Update 'type' with the result
of maybe_process_partial_specialization in the
nested_name_specifier branch. Refactor nearby code to accomodate
that maybe_process_partial_specialization returns a _TYPE, not a
TYPE_DECL, and eliminate local variable 'class_type' in passing.
gcc/testsuite/ChangeLog:
* g++.dg/cpp2a/concepts-partial-spec10.C: New test.
* g++.dg/cpp2a/concepts-partial-spec11.C: New test.