struct Fns {
    f1 fn () @[required]
    f2 fn () @[attr1; required]
}

fn func() {
}

fn test_struct_fields_storing_required_functions() {
    s := Fns{
        f1: func
        f2: func
    }

    assert s.f1 == func
    assert s.f2 == func
}

struct Data {
    v1 int @[required]
    v2 int @[required]
}

fn test_required_fields() {
    data := Data{1, 2}
    assert data.v1 == 1
    data2 := Data{
        ...data
        v1: 10
    }
    assert data.v2 == data2.v2
}