It's kind of crazy that OOO is sold to people as 'thinking about the world as objects' and then people expect to have an object, randomly take out a part, do whatever they want with it and just stick it back in and voila
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.
I recently had this problem is some rust code. I was implementing A and had some code that would decide which of several 'B's to use. I then wanted to call an internal method on A (that takes a mutable reference to A) with a mutable reference to the B that I selected. That was obviously rejected by the compiler and had to find a way around it.
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.