{"ast_node_type":"other","tokens":[{"end":22,"kind":"keyword","start":0,"text":"tcx.mk_fn_sig("}]}
        tcx.mk_fn_sig(
    let poly_sig = args.as_coroutine_closure().coroutine_closure_sig().map_bound(|sig| {
            [self_ty].into_iter().chain(sig.tupled_inputs_ty.tuple_fields()),