https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94310
--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Potential fix:
--- a/gcc/cp/parser.c
+++ b/gcc/cp/parser.c
@@ -16982,6 +16982,15 @@ cp_parser_template_name (cp_parser* parser,
decl = strip_using_decl (decl);
+ if (TREE_CODE (decl) == USING_DECL
+ && TREE_CODE (USING_DECL_SCOPE (decl)) == TYPE_PACK_EXPANSION)
+ {
+ tree t = PACK_EXPANSION_PATTERN (USING_DECL_SCOPE (decl));
+ t = get_template_info (t);
+ if (t)
+ decl = TI_TEMPLATE (t);
+ }
+
/* If DECL is a template, then the name was a template-name. */
if (TREE_CODE (decl) == TEMPLATE_DECL)
{
