{"ast_node_type":"import","tokens":[{"end":73,"kind":"keyword","start":0,"text":"//"}]}
    // Coverage mappings use the high bit of `end_col` to indicate that a
    let all_nonzero = [start_line, start_col, end_line, end_col].into_iter().all(|x| x != 0);
    // region is actually a "gap" region, so make sure it's unset.