{"ast_node_type":"variable","tokens":[{"end":50,"kind":"keyword","start":0,"text":"let"}]}
    let crate_name = tcxt.crate_name(LOCAL_CRATE);
    let hash = tcxt.crate_hash(LOCAL_CRATE);
    let metrics_file_name = format!("unstable_feature_usage_metrics-{crate_name}-{hash}.json");