{"ast_node_type":"other","tokens":[{"end":85,"kind":"keyword","start":0,"text":"self.demand_suptype(span,"}]}
        self.demand_suptype(span, args.tupled_upvars_ty(), final_tupled_upvars_type);
        let final_tupled_upvars_type = Ty::new_tup(self.tcx, &final_upvar_tys);