Cannot convert return expression of type 'child' to return type T

I am struggling a bit with generics in Swift.

I have the following code:

class Parent {
    init(value: SomeThing) {
        // ...
    }

    func clone<T: Parent>() -> T {        
        return T(value: SomeThing)
    }
}

class Child : Parent {
    var otherValue: SomeThingElse?

    override func clone<T>() -> T where T : Parent {        
        let clone: Child = super.clone()
        clone.otherValue = self.otherValue
        return clone  //ERROR: cannot convert return expression of type 'Child' to return type T
    }
}

The idea is to create a simple method that returns a new copy of a child instance with identical values. I don't want to write the constructor out for each Child classtype. (it has a lot of params in the real classes, and I like to keep it clean).

The error I get is: cannot convert return expression of type 'Child' to return type T Suggested solution is to make it return clone as! T. But that way I lose the reason to use a generic class.

Any idea how to solve this while keeping it generic and not write out the constructor in each class?