This is honestly such an insane take when you think about what the physical analogue would be (which again, is how OOP is sold).
The proper thing here is that, if A is the thing, then you really only have an A and your reference into B is just that, And should be represented as such, with appropriate syntactic sugar. In Haskell, you would keep around A and use a lens into B and both get passed around separately. The semantic meaning is different.