{"ast_node_type":"other","tokens":[{"end":91,"kind":"keyword","start":0,"text":".unwrap_or_else(||"}]}
        .unwrap_or_else(|| bug!("encode_fnsig: invalid option(s) `{:?}`", options.bits()));
    let transform_ty_options = TransformTyOptions::from_bits(options.bits())
    let mut type_folder = TransformTy::new(tcx, transform_ty_options);