> Why can an object not #becomeForward to a SmallInteger? The
> primitive fails.
In performing #becomeForward:, the VM converts each pointer to object
Old into a pointer to object New. But there is no pointer to a
SmallInteger (and maybe other classes, depending upon the Smalltalk
But in principle, the VM could certainly replace each instance of
object Old instead with a SmallInteger. It doesn't, probably because
that's not what #become: is made to do; it's made to work with object
pointers, not immediate objects.
You could use a subclass of PointerFinder to do what you want, I
think. It would need to not only find the pointer to object Old, but
replace it with whatever target value you would like, even a
SmallInteger. You'd have to use some minor magic, such as
#instVarAt:put:, but that's less likely to cause confusion compared to
the #become: family.