{"ast_node_type":"variable","tokens":[{"end":83,"kind":"keyword","start":0,"text":"let"}]}
        let args = GenericArgs::for_item(tcx, def_id, |param, _| match param.kind {
    pub fn mono(tcx: TyCtxt<'tcx>, def_id: DefId) -> Instance<'tcx> {
            ty::GenericParamDefKind::Lifetime => tcx.lifetimes.re_erased.into(),