interface TheInterfaceItself {
    f() int
}

struct SomeImplForTII1 {}

fn (_ SomeImplForTII1) f() int {
    return 2
}

fn (_ SomeImplForTII1) secret1() int {
    return 42
}

struct AnotherImplementation {}

fn (_ AnotherImplementation) f() int {
    return 8
}

fn (_ AnotherImplementation) secret2() int {
    return 84
}

fn h(foo TheInterfaceItself, i int) int {
    j := foo.f()
    match i {
        0 {
            return j + (foo as SomeImplForTII1).secret1()
        }
        1 {
            return j + (foo as AnotherImplementation).secret2()
        }
        else {
            return 1
        }
    }
}

fn test_casting_to_impl() {
    assert h(SomeImplForTII1{}, 0) == 44
    assert h(AnotherImplementation{}, 1) == 92
}