type SumType = int | string | f64

struct Foo[T] {
    field ?SumType
}

fn t[T](val Foo[T]) {
    if val.field != none {
        if val.field is string {
            dump(val.field)
            assert val.field == 'foo'
        } else if val.field is int {
            dump(val.field)
            assert val.field == 1
        } else if val.field is f64 {
            dump(val.field)
            assert val.field == 1.23
        }
    } else {
        dump(val.field)
        assert val.field == none
    }
}

fn test_main() {
    t(Foo[int]{})
    t(Foo[string]{})
    t(Foo[f64]{})

    t(Foo[int]{ field: 1 })
    t(Foo[string]{ field: 'foo' })
    t(Foo[f64]{ field: 1.23 })
}