{"ast_node_type":"variable","tokens":[{"end":97,"kind":"keyword","start":0,"text":"let"}]}
    let new_lifetime_param = generate_unique_lifetime_param_name(impl_def.generic_param_list())?;
) -> Option<()> {
    acc.add(AssistId::refactor(ASSIST_NAME), ASSIST_LABEL, lifetime_loc, |builder| {