because each @|ichain| must have as a prefix the @|ichain| for each
superclass in the same chain, and each slot must be stored in exactly one
place. The layout of vtables doesn't have this second requirement: it
because each @|ichain| must have as a prefix the @|ichain| for each
superclass in the same chain, and each slot must be stored in exactly one
place. The layout of vtables doesn't have this second requirement: it