{"ast_node_type":"other","tokens":[{"end":100,"kind":"keyword","start":0,"text":"trace!(?r,"}]}
            trace!(?r, liveness_constraints=?self.liveness_constraints.pretty_print_live_points(r));
            // First look for some `r` such that `fr1: r` and `r` is live at `location`
            self.liveness_constraints.is_live_at(r, location)