{"ast_node_type":"variable","tokens":[{"end":50,"kind":"keyword","start":0,"text":"let"}]}
                let closure = match args.first() {
            if self.infcx.tcx.is_lang_item(self.infcx.tcx.parent(id), LangItem::FnOnce) {
                    Some(Spanned { node: Operand::Copy(place) | Operand::Move(place), .. })