{"ast_node_type":"variable","tokens":[{"end":80,"kind":"keyword","start":0,"text":"let"}]}
    let after_second_colon = source_map.span_take_while(from_second_colon, |c| {
    // Find the first non-whitespace character in `from_second_colon`.. `f`
        if found_a_non_whitespace_character {