Critic notes about Swift Range types jungle

[Lantua]

Amongst other things:

Unify and expand Range and its likes

There are some technical barriers to this change, like source and ABI compatibility, but I’m going to put those aside, because there’s a more important issue: we wouldn’t want this design. We’ve considered similar ones in the past, but we rejected them in favor of the current solution, where decisions about boundary and direction are baked into the type. Let me explain why. 1. The current design enforces the correctness of iteration. For instance, suppose you try to do this: let myRange = ..<…