{"ast_node_type":"other","tokens":[{"end":61,"kind":"keyword","start":0,"text":"TyKind::CoroutineWitness(coroutine_a,"}]}
                TyKind::CoroutineWitness(coroutine_a, sub_a),
            (
                TyKind::CoroutineWitness(coroutine_b, sub_b),