https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94799
--- Comment #13 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
The fix may be as easy as this:
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -23812,8 +23812,8 @@ cp_parser_class_name (cp_parser *parser,
/* Any name names a type if we're following the `typename' keyword
in a qualified name where the enclosing scope is type-dependent. */
- typename_p = (typename_keyword_p && scope && TYPE_P (scope)
- && dependent_type_p (scope));
+ typename_p = (typename_keyword_p && parser->scope && TYPE_P (parser->scope)
+ && dependent_type_p (parser->scope));
/* Handle the common case (an identifier, but not a template-id)
efficiently. */
if (token->type == CPP_NAME
