{"ast_node_type":"other","tokens":[{"end":40,"kind":"keyword","start":0,"text":"pub(crate)"}]}
    pub(crate) array_len: Option<usize>,
    /// `None` if the matched value is a slice, `Some(n)` if it is an array of size `n`.
    /// The kind of pattern it is: fixed-length `[x, y]` or variable length `[x, .., y]`.