Stack overflow

[Namespace]

> Wait, you have a template mixin inside of Foo which passes Foo 
> to it? I don't
> know if you can get away with that or not, since you're trying 
> to pass a type
> to a template while you're adding stuff to it via that 
> template. So, the type
> is incomplete. I'm willing to be that that's your problem, but 
> I don't know.
>
> - Jonathan M Davis

If so, the problem would have to solved if i switch from a mixin 
to an abstract class. Or not?
Or have you any other idea?