{"ast_node_type":"variable","tokens":[{"end":84,"kind":"keyword","start":0,"text":"let"}]}
    let (open, open_ch) = snippet.char_indices().find(|&(_, c)| "([{".contains(c))?;
    let snippet = cx.sess().source_map().span_to_snippet(span).ok()?;
    let close = snippet.rfind(|c| ")]}".contains(c))?;