How to represent value based classes ?

John Rose john.r.rose at
Mon Jul 23 21:07:42 UTC 2018

On Jul 23, 2018, at 2:03 PM, John Rose <john.r.rose at> wrote:
> Right. And I don’t see any case where we would care about null handling where we would not *also* care about the layout. In the case of the verifier, a checkcast instruction will convert from a null reference to a VT or VBC without caring which case it is. After linking, the checkcast could either NPE or substitute the default value.

There are other times like this when we need nullability info, but I think the verifier is the extreme case, and if we can solve that one (as above) then others can be handled by similar tricks, which make an early decision (allow the checkcast) and refine it later (after linking decide the precise behavior). 

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