class RuboCop::Cop::Lint::DuplicateMagicComment

def magic_comment_lines
  comment_lines = { encoding_magic_comments: [], frozen_string_literal_magic_comments: [] }
  leading_magic_comments.each.with_index do |magic_comment, index|
    if magic_comment.encoding_specified?
      comment_lines[:encoding_magic_comments] << index
    elsif magic_comment.frozen_string_literal_specified?
      comment_lines[:frozen_string_literal_magic_comments] << index
    end
  end
  comment_lines
end

def on_new_investigation
  return if processed_source.buffer.source.empty?
  magic_comment_lines.each_value do |comment_lines|
    next if comment_lines.count <= 1
    comment_lines[1..].each do |comment_line|
      range = processed_source.buffer.line_range(comment_line + 1)
      register_offense(range)
    end
  end
end

def register_offense(range)
  add_offense(range) do |corrector|
    corrector.remove(range_by_whole_lines(range, include_final_newline: true))
  end
end