{"ast_node_type":"other","tokens":[{"end":21,"kind":"keyword","start":0,"text":"self,"}]}
                self,
            (TyKind::Adt(id_a, sub_a), TyKind::Adt(id_b, sub_b)) if id_a == id_b => zip_substs(
                Some(self.unification_database().adt_variance(*id_a)),