{"ast_node_type":"other","tokens":[{"end":84,"kind":"keyword","start":0,"text":"(ReBound(..),"}]}
            (ReBound(..), _) | (_, ReBound(..)) | (ReErased, _) | (_, ReErased) => {
        match (a.kind(), b.kind()) {
                bug!("cannot relate region: LUB({:?}, {:?})", a, b);