cattr_test.rb

require 'active_support/all'

class A
  cattr_accessor :hoge
  class << self
    attr_accessor :moge
  end
end

class B < A; end

A.hoge # => nil
A.moge # => nil

B.hoge = 1
B.moge = 2

A.hoge # => 1
A.moge # => nil