{"ast_node_type":"other","tokens":[{"end":80,"kind":"keyword","start":0,"text":"ty::InstanceKind::ClosureOnceShim"}]}
        ty::InstanceKind::ClosureOnceShim { call_once: _, track_caller: _ } => {
        }
            let fn_mut = tcx.require_lang_item(LangItem::FnMut, DUMMY_SP);