EG meeting, 2021-11-17

[Dan Heidinga]

>> "identityless objects and the type hierarchy": discussed how the IdentityObject/PrimitiveObject interfaces are used in the "Consolidating the user model" world
>
>
> For the moment I think this does probably carry over to WithIdentity/WithoutIdentity or whatever they are called. The question I think is still open (to me) is whether there really are active contractual implications of being identityless or if it's equivalent to being uncommitted; i.e. should a clear-cut identityless class still be able to have an identityful subclass, or does that clearly break something.

It breaks flattening.  If an identityless class is flattened - and we
want to preserve the option to do this for bucket 2 values that are <=
64 bits - then we can't assign a subclass instance to a slot (field /
array element) declared to be the superclass's type as we may have to
truncate the subclass to have it fit.

--Dan