{"ast_node_type":"variable","tokens":[{"end":62,"kind":"keyword","start":0,"text":"let"}]}
    let (min_or_exact_args, max_args) = match ident.as_str() {
    // `None` for max indicates the arg count must be exact, `Some` indicates a range is accepted.
        "concat" => panic!("concat takes unlimited tokens but didn't eat them all"),