{"ast_node_type":"other","tokens":[{"end":60,"kind":"keyword","start":0,"text":"//"}]}
    // meta-variable is found. The innermost stack is first.
    // Accumulates the stacks the operators of each state until (and including when) the
    let mut acc: SmallVec<[&SmallVec<[KleeneToken; 1]>; 1]> = SmallVec::new();