Open Radar

 
Summary:
A factory method that should create an instance of a generic type creates the wrong instance. It seems related to which type constraint that is set since setting the constraint to "NSObject" instead of "Vehicle" makes the correct instance type.

Steps to Reproduce:
Insert this sample code in Playground:


import Foundation

class Vehicle {
    func getType() -> String {
        return "vehicle"
    }
}

class Bicycle: Vehicle{
    override func getType() -> String {
        return "bicycle"
    }
}

func construct<T : Vehicle>() -> T { //NB: Change constraint to NSObject (and let vehicle subclass NSObject), and it all works
    return T()
}

let a : Bicycle = construct()
println ("\(a.getType())")   //Expected "Bicycle". Got "Vehicle"

Expected Results:
I expected a Bicycle object to be created since that is the generic type (can be verified by printing out the type in the "construct" function

Actual Results:
A Vehicle object was created