{"ast_node_type":"function","tokens":[{"end":76,"kind":"keyword","start":0,"text":"fn"}]}
    fn check_relation(&self, r_a: Region<'tcx>, r_b: Region<'tcx>) -> bool {
    /// Check whether `r_a <= r_b` is found in the relation.
        r_a == r_b || self.relation.contains(r_a, r_b)