{"ast_node_type":"variable","tokens":[{"end":59,"kind":"keyword","start":0,"text":"let"}]}
    let metrics_path = metrics_dir.join(metrics_file_name);
    let metrics_file_name = format!("unstable_feature_usage_metrics-{crate_name}-{hash}.json");
    if let Err(error) = tcxt.features().dump_feature_usage_metrics(metrics_path) {