Ruby allocation calling mixin

allocations.rb

module Foo
  def foo
    bar
  end

  def bar
  end
end

class Whatever
  include Foo
end

class SomethingElse
  def foo
    bar
  end

  def bar
  end
end

something_else = SomethingElse.new
start = GC.stat(:total_allocated_objects)
something_else.foo
puts GC.stat(:total_allocated_objects) - start
# => 0 (this is what I expected)

whatever = Whatever.new
start = GC.stat(:total_allocated_objects)
whatever.foo
puts GC.stat(:total_allocated_objects) - start
# => 2 (huh)?

That means it can't be a Ruby object but some internal data structure allocated by Ruby.