{"ast_node_type":"other","tokens":[{"end":65,"kind":"keyword","start":0,"text":"assert!(self.universal_regions.is_universal_region(fr1));"}]}
        assert!(self.universal_regions.is_universal_region(fr1));
    pub(crate) fn postdom_upper_bound(&self, fr1: RegionVid, fr2: RegionVid) -> RegionVid {
        assert!(self.universal_regions.is_universal_region(fr2));