{"ast_node_type":"other","tokens":[{"end":100,"kind":"keyword","start":0,"text":"cx.tcx.sess.source_map().span_to_snippet(ty.span).unwrap_or_else(|_|"}]}
                    cx.tcx.sess.source_map().span_to_snippet(ty.span).unwrap_or_else(|_| "_".into())
                GenericArg::Type(ty) => {
                }