Naw. Youre thinking inheritance. That's not what it is. Inheritance can be used in FP. It's not uniquely OOP at all. The only thing uniquely OOP is the concept of setters. It's fundamental and isn't some side concept either. Setters are fundamental to how you program in OOP. OOP is basically a graph of objects mutating one another.

Setters are not used in any other programming paradigm. Not in FP, not in C style programming... Any style of programming that strictly is not OOP does not use setters.