{"ast_node_type":"other","tokens":[{"end":80,"kind":"keyword","start":0,"text":"extern_abi_stability(abi).or_else(|unstable"}]}
    extern_abi_stability(abi).or_else(|unstable @ UnstableAbi { feature, .. }| {
) -> Result<(), UnstableAbi> {
        if features.enabled(feature) || span.allows_unstable(feature) {