{"ast_node_type":"other","tokens":[{"end":74,"kind":"keyword","start":0,"text":"(TyKind::Tuple(arity_a,"}]}
            (TyKind::Tuple(arity_a, sub_a), TyKind::Tuple(arity_b, sub_b))
            ) if assoc_ty_a == assoc_ty_b => zip_substs(self, None, sub_a, sub_b)?,
                if arity_a == arity_b =>