{"ast_node_type":"function","tokens":[{"end":60,"kind":"keyword","start":0,"text":"fn"}]}
    fn new(tcx: TyCtxt<'tcx>) -> LibFeatureCollector<'tcx> {
impl<'tcx> LibFeatureCollector<'tcx> {
        LibFeatureCollector { tcx, lib_features: LibFeatures::default() }