{"ast_node_type":"function","tokens":[{"end":62,"kind":"keyword","start":0,"text":"fn"}]}
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
impl<'tcx, O: fmt::Debug> fmt::Debug for traits::Obligation<'tcx, O> {
        if ty::tls::with(|tcx| tcx.sess.verbose_internals()) {