> To achieve the same result (avoid unexpected endless loops) can't we
> just say in -5- that, if one form is overridden, the other must be
> (consistently) overridden too or undefined behavior is expected?
>
> Is *this* too strong, in a different way? I don't know, but really,
> that 12988 is missing the other form is at the root of the whole
> discussion thread, in my opinion...
I would like to think that this requirement is already covered
by paragraph 4 above (i.e., both functions must return the same
result). Exactly how it's achieved shouldn't matter, although in
practice it will most likely mean that if one is overridden to
return a result that's different from the base, the other will
have to be overridden as well.