How to properly implement the Equatable protocol in a class hierarchy?

Question

I\'m trying to implement the == operator (from Equatable) in a base class and its subclasses in Swift 3. All of the classes will only be used in Sw

Answer 1

Following the other answers I came up with this:

class Base : Equatable {
    var x : Int
    static func == (lhs: Base, rhs: Base) -> Bool {
        return lhs.x == rhs.x
    }
}

class Subclass : Base {
    var y : String
    static func == (lhs: Subclass, rhs: Subclass) -> Bool {
        return lhs.y == rhs.y && (lhs as Base) == (rhs as Base)
    }
}