{"ast_node_type":"other","tokens":[{"end":58,"kind":"keyword","start":0,"text":"CanonicalizeMode::Response"}]}
                    CanonicalizeMode::Response { .. } => {
                    CanonicalizeMode::Input(_) => CanonicalVarKind::Region(ty::UniverseIndex::ROOT),
                        CanonicalVarKind::Region(self.delegate.universe_of_lt(vid).unwrap())