{"ast_node_type":"variable","tokens":[{"end":60,"kind":"keyword","start":0,"text":"let"}]}
            let trait_args = tcx.mk_args(&[drop_ty.into()]);
            let drop_fn_def_id = tcx.require_lang_item(LangItem::AsyncDropInPlace, span);
            let sig = tcx.fn_sig(drop_fn_def_id).instantiate(tcx, trait_args);