{"ast_node_type":"other","tokens":[{"end":17,"kind":"keyword","start":0,"text":"bug!("}]}
            bug!(
        if let Some(old) = self.rbv.late_bound_vars.insert(hir_id.local_id, binder) {
                "overwrote bound vars for {hir_id:?}:\nold={old:?}\nnew={:?}",