{"ast_node_type":"variable","tokens":[{"end":55,"kind":"keyword","start":0,"text":"let"}]}
    let t = tcx.type_of(def_id).instantiate_identity();
fn check_simd(tcx: TyCtxt<'_>, sp: Span, def_id: LocalDefId) {
    if let ty::Adt(def, args) = t.kind()