o = Object.new
    class << o
      private
      def foo; 42; end
      def [](i); 42; end
      def foo=(a); 42; end
      def []=(i, a); 42; end
    end

    assert_raise(NoMethodError) {
      o.instance_eval {o.foo = 1}
    }
    assert_nothing_raised(NoMethodError) {
      assert_equal(1, o.instance_eval {self.foo = 1})
    }

    assert_raise(NoMethodError) {
      o.instance_eval {o[0] = 1}
    }