Initializing derived class enum with (unscoped) base class enum having the same name

Question

The following code (also on ideone) looks like it shouldn't compile but it does on MSVC 2008 and GCC 4.8.2

#include<iostream>

struct Base
{
    enum State { ON = 11 , OFF = 22 , STANDBY = 33 };
};

struct Derived : Base
{
    enum State { ON = ON , OFF = OFF };  // Huh?
};

int main()
{
    std::cout << Derived::ON << std::endl;
}

Is it standard compliant?

Answer 1

enum State { ON = ON , OFF = OFF };  // Huh?
                  ^^

At this point derived re-definition is not complete, so ON used would be from Base.