{"ast_node_type":"variable","tokens":[{"end":68,"kind":"keyword","start":0,"text":"let"}]}
    let middle = l_span.shrink_to_hi().until(r_span.shrink_to_lo());
    let left = e.span.shrink_to_lo().until(l_span.shrink_to_lo());
    let right = r_span.shrink_to_hi().until(e.span.shrink_to_hi());