[Dewie3]

> Nil is a useful modelling tool, even in Rust where it exists via Option<>/None, correct?

Yes. So? A lot of things are useful modelling tools, but that doesn't mean you necessarily want to include them in every reference-like type. A tuple of two things is useful modelling tool; should that then be infused into every type? A "either value or error" is a useful type; should that be infused into every type?

No? Then what makes "Either something or nothing" so special?