{"ast_node_type":"other","tokens":[{"end":93,"kind":"keyword","start":0,"text":".filter_map(|fr|"}]}
                .filter_map(|fr| self.region_vid_to_name(mbcx, *fr).map(|rname| (fr, rname)))
                // if there is a `None`, we will just omit that constraint
                .collect::<Vec<_>>();