> * [LibraryEvolution.rst] @noreturn is a versioned attribute, so how will this > proposal affect that design?
If library evolution permitted you to change a return type into one of its subtypes (for instance, to change an NSObject return into an NSResponder return), and if Never were a subtype-of-all-types bottom type, then you would always be able to change any return type to Never. There may be ABI reasons that this couldn't be supported—for instance, a Boolean existential has a different representation than a concrete Bool struct—but I believe it would be semantically sound. (Of course, if you had to write `Any<Boolean>` instead of `Boolean`, the fact that you couldn't replace it with `Bool` would be a little more straightforward to understand...) -- Brent Royal-Gordon Architechies _______________________________________________ swift-evolution mailing list [email protected] https://lists.swift.org/mailman/listinfo/swift-evolution
