class Parent < ActiveRecord::Base
  has_many :children, ->() { order('id DESC') }, dependent: :destroy do
    def xyzyyx
       ...
    end
    ...
  end
end

Parent.includes(:children).to_a

gem 'activerecord', '4.2.0'
require 'active_record'
require 'minitest/autorun'

ActiveRecord::Base.establish_connection(adapter: 'sqlite3', database: ':memory:')
ActiveRecord::Base.default_timezone = :local

ActiveRecord::Schema.define do
  create_table(:parents)
  create_table(:children) { |t| t.integer :parent_id }
end

class Parent < ActiveRecord::Base
  has_many :children, ->() { order('id DESC') }, dependent: :destroy do
  end
end

class Child < ActiveRecord::Base
end

class Bug < Minitest::Test
  def test_preloading_of_associations
    Parent.create!
    Parent.create!
    Parent.includes(:children).to_a
  end
end

def initialize(model, name, scope, options)
  super
  @mod = nil
  if block_given?
    @mod = Module.new(&Proc.new)
    @scope = wrap_scope @scope, @mod
  end
end

def wrap_scope(scope, mod)
  if scope
    proc { |owner| instance_exec(owner, &scope).extending(mod) }
  else
    proc { extending(mod) }
  end
end