[swift-evolution] [Review] SE-0065 A New Model for Collections and Indices

[Joe Groff]

> 	• Because Swift is unable to express conditional protocol conformances, implementing this change has required us to create a great deal of complexity in the standard library API. Aside from the two excess “Countable” range types, there are new overloads for slicing and twelve distinct slice types that capture all the combinations of traversal, mutability, and range-replaceability. While these costs are probably temporary, they are very real in the meantime.

Is there a migration strategy possible for when we do support conditional conformances? Would typealiasing the existing names to refinements of a more general Slice<T> type be sufficient?

-Joe