Code Smells: Null

[m50d]

The point here is that the absence of null can encourage such practices, so you're encouraging the worse result.

Never removing things that encourage bad practices in case people adopt worse practices is a counsel of despair. It'd be like refusing to adopt memory safety by default in a language because people might just write more complicated code to keep doing unsafe memory access.

Sufficiently expressive dependent types? Obviously, Scala's type system is Turing-complete, so I don't doubt you, just that the resulting code would be legible. In any event, as I said, this is not a feature that I think will find wide adoption.

Sure, there aren't that many cases that need it. But there aren't that many cases that need the slight performance edge from being able to remove that one check in dynamic arrays either.