enumerable.rb

using Module.new {
  refine Enumerable do
    alias :orig_sum :sum
  end
}

module Enumerable
  def sum(...)
    p method(:orig_sum)
  end
end

class A
  include Enumerable
end

class B
  include Enumerable

  def sum(...)
    super
  end
end

p RUBY_VERSION

A.new.sum
B.new.sum