Spec for scope resolution when overriding private methods

Hi,

I've been looking for an official answer for this behavior:
http://stackoverflow.com/questions/3756609/strange-behavior-when-overriding-private-methods

There's one explanation that seems reasonable, but I'm not sure if it's an
implementation detail or if it should be part of the spec. I couldn't find
anything in the repo. In particular, I've looked at

https://github.com/php/php-langspec/blob/master/spec/14-classes.md

and

https://github.com/php/php-langspec/blob/master/spec/10-expressions.md#scope-resolution-operator

Is it something that we should include in the spec? (In case it's already
there, could you point me to the right page/section?)

Thanks,