A Swift protocol requirement that can only be satisfied by using a final class

Question

I\'m modeling a owner/ownee scheme on Swift:

class Owner {
     // ...
}

protocol Ownee {
    var owner: Owner { get }
}
         


        

Answer 1

The following syntax should support what you're after:

protocol Ownee {
    associatedtype Owned = Self where Owned:Ownee
    var owner: Owner { get }
}

(tested using Swift 4 - Beta 1)