Swift: Convenience initializers - Self used before self.init call

Question

We are getting the following error on the convenience method below:

Self used before self.init call

class MyClass {
    var id : Int        
    var desc : String

    init?(id : Int, desc : String) {
        self.id = id
        self.desc = desc
    }

    convenience init?(id : Int?) {
        guard let x = id else {
            return
        }
        self.init(id : x, desc : "Blah")
    }
}

How can we implement this type of behavior in Swift?

Solution

As Leo already pointed out, the quickest way of appeasing the compiler is to return nil inside the guard statement.

convenience init?(id : Int?) {
    guard let x = id else {
        return nil
    }
    self.init(id: x, desc: "Blah")
}

Unless there is a specific reason to do so, you can also avoid using a failable initializer in the first place.init(id : Int, desc : String) compiles just fine.

Comments

[Leo Dabus]

Just return nil