Open Radar

 
This code in a playground == not happy:

import Foundation

protocol Test {
    func getAValue() -> Int
}

@objc class SuperClass {}

class TestClass: SuperClass {
    func getAnotherValue() -> Int {
        return requiresTest(self)
    }
}

let foo = TestClass() // Error: EXC_BAD_INSTRUCTION

foo.getAnotherValue()

func requiresTest(x: Test) -> Int {
    return x.getAValue()
}

extension TestClass: Test {
    func getAValue() -> Int {
        return 42
    }
}