class RuboCop::Cop::Performance::Sample

def range_size(range_node)
  vals = range_node.to_a
  return :unknown unless vals.all?(&:int_type?)
  low, high = vals.map { |val| val.children[0] }
  return :unknown unless low.zero? && high >= 0
  case range_node.type
  when :erange
    (low...high).size
  when :irange
    (low..high).size
  end
end