{"ast_node_type":"variable","tokens":[{"end":44,"kind":"keyword","start":0,"text":"let"}]}
    let hash = tcxt.crate_hash(LOCAL_CRATE);
fn dump_feature_usage_metrics(tcxt: TyCtxt<'_>, metrics_dir: &Path) {
    let crate_name = tcxt.crate_name(LOCAL_CRATE);