{"ast_node_type":"variable","tokens":[{"end":78,"kind":"keyword","start":0,"text":"let"}]}
    let param_env = ty::ParamEnv::new(tcx.mk_clauses_from_iter(hybrid_preds));
        .map(|(clause, _)| clause);
    let param_env = normalize_param_env_or_error(tcx, param_env, ObligationCause::dummy());