How to make protocol only usable by certain classes

Question

Im making a protocol but I only want it to be implementable by View Controllers. Im doing this to keep the code consistent and to try and avoid confusion for someone new to the project.

I was also wondering if by making a protocol only extendable by a UIViewController would I be able to access the UIViewControllers variables?

Answer 1

protocol P where Self: UIViewControlller {

}