[davesque]

To me, automatic Maybe inference seems correct. I don't think the concerns about types being broken (when one makes `u` total) are valid. That's really the point of a strong type system. You get the errors at compile time and they show you that the semantics of your program are inconsistent. My only issue with it is that it's a little too "magical". I'd rather that the behavior of record functions be more explicit. That makes lenses seem more attractive, as you mentioned.