pub(crate) fn calculate_after_context(
    lines: &[(Option<LineNumber>, Option<LineNumber>)],
    opposite_to_lhs: &HashMap<LineNumber, HashSet<LineNumber>, BuildHasherDefault<FxHasher>>,
    opposite_to_rhs: &HashMap<LineNumber, HashSet<LineNumber>, BuildHasherDefault<FxHasher>>,
    max_lhs_src_line: LineNumber,
    max_rhs_src_line: LineNumber,
    num_context_lines: usize
) -> Vec<(Option<LineNumber>, Option<LineNumber>)>