Not able to reproduce with Xcode 13 beta 2 or main. Is that the only code, or is there more to it? Are you seeing a compiler error (if so, what is the error)? Is the problem that the availability annotations are not being honored correctly?

@swift-ci create

Comment by Gereon Steffens (JIRA)

The attached project shows the issue, it builds in Xcode 12.5.1 and fails to build in Xcode 13 beta 2.

The error message is

Enum cases with associated values cannot be marked potentially unavailable with '@available'

on line 11 of ViewController.swift.

A couple of other reports of this issue can be found at https://developer.apple.com/forums/thread/682351

Comment by Gereon Steffens (JIRA)

I first came across this issue when trying to build a project targeting iOS 12, which includes the SwiftMessages library, and building that failed on https://github.com/SwiftKickMobile/SwiftMessages/blob/master/SwiftMessages/SwiftMessages.swift#L82

Huh, that's weird. I don't see the error when the availability annotation uses 13.0 but I do see the error when it is 14.0. The app's own deployment target is 13.0, which seems related.

This is intentional. The ABI of enum cases with payloads that are potentially unavailable is not well-defined. That this worked in the past was by coincidence of your application not requiring the (potentially unavailable) type metadata for the payload. Please either increase your deployment target or mark Foo itself as available as the least-available case.

#36327

Comment by Spandana Batchu (JIRA)

Gereon (JIRA User) Im using SwiftMessages library and I see the same issue with Xcode 13 Beta. How did you resolve the issue?

spandanabatchu (JIRA User) You (or SwiftMessages) must resolve this issue by either

1) Increasing your deployment target
2) Lowering the availability restriction
3) Removing the annotation altogether

The compiler is warning you that the availability bounds there are not meaningful and may lead to poor behavior if relied upon for their intended purpose.

Comment by Gereon Steffens (JIRA)

spandanabatchu (JIRA User) there is a workaround described here: SwiftKickMobile/SwiftMessages#471 (comment)