Open Radar

 
Summary:
The compiler should error when a subclass overrides a function with a contravariant return type.
There shouldn't be ann EXC_BAD_ACCESS at runtime.

Steps to Reproduce:
Compile + run the following swift code:

class A {
    class func f() -> String? {
        return nil
    }
}

class B : A {
    override class func f() -> String {
        return "this should be printed!"
    }
}

println(B.f())
B()

Expected Results:
The compiler should error when a subclass overrides a function with a contravariant return type.
There shouldn't be ann EXC_BAD_ACCESS at runtime.

Actual Results:
The code compiles and there’s an EXC_BAD_ACCESS at runtime.