protocol Food {}

class Meat: Food {
    var a = 0, b = 0, c = 0, d = 0
}

class Cake: Food {}

class Person {
    func eat<T : Food>(_: T) {
        print("eat food")
    }
}

class Man : Person {
    override func eat<T : Meat>(_ m: T) {
        print("eat meat", m.d) // EXC_BAD_ACCESS
    }
}

let man: Person = Man()
man.eat(Cake())

class A {
    var a = 1
}

class B : A {
    var b = 2
}

class Person {
    func eat<T : A>(_ : T) {
        print("eat A")
    }
}

class Man : Person {
    override func eat<T : B>(_ t: T) {
        print("eat B", t.b) // EXC_BAD_ACCESS
    }
}

let man: Person = Man()
man.eat(A())