class RuboCop::Cop::Rails::EnumHash

def on_send(node)
  enum?(node) do |pairs|
    pairs.each do |pair|
      key, array = array_pair?(pair)
      next unless key
      add_offense(array, message: format(MSG, enum: enum_name(key))) do |corrector|
        hash = array.children.each_with_index.map do |elem, index|
          "#{source(elem)} => #{index}"
        end.join(', ')
        corrector.replace(array.loc.expression, "{#{hash}}")
      end
    end
  end
end