StackOverflow#36799396

test.rb

# in-ruby-is-it-possible-to-move-a-module-up-the-ancestor-chain
# http://stackoverflow.com/questions/36799396
module A
  def hiya(str)
    puts "ho #{str}"
  end
  def if_what?
  end
end

module D
  def hiya(str)
    puts "hi #{str}"
  end
  def what_if?
  end
end

module B
  include D
end

class Base
  include A
end

class C1 < Base
  include B
end

class C2
  include D
end

p C1.ancestors #=> [C1, B, D, A, Object, Kernel, BasicObject] 
p C2.ancestors #=> [C2, D, Object, Kernel, BasicObject] 

C1.new.hiya("Lois") #=> hi Lois
C2.new.hiya("Lois") #=> hi Lois

p D.instance_methods

(A.instance_methods & D.instance_methods).each { |m| D.send(:remove_method, m) }

p D.instance_methods

C1.new.hiya("Lois") #=> ho Lois
C2.new.hiya("Lois") #=> error - undefined method

#=> not an acceptable solution to the problem.