Xcode 11 Beta won't build because of WatchKit?

I had the same issue for one swift file in the WatchKit Extension. It turned out that it was a member of both the iOS app and the WatchKit Extension. I unticked the iOS app in the target membership section for the file so that it only belongs to the WatchKit Extension target. Now the project builds successfully.

Some of the functionality to communicate between the Apple watch with the iPhone/iPad used to be implemented within the WatchKit framework. But at some point it got moved into the WatchKitConnectivity framework.

If you look in your Target's "Build Phase" -> "Link Binary With Libraries" section, you will see the "WatchKit.framework" with "Optional" status. iOS13+ has become more "strict" so it won't build unless I completely remove the "WatchKit.framework", and instead add "WatchConnectivity.framework".

Also make sure your iPhone/iPad code refers use "import WatchConnectivity" instead of "import WatchKit".

We need to use "Conditional Imports" to resolve the issue.

Replace the import WatchKit header with the below code :

#if !os(iOS)
import WatchKit
#endif

This resolved my issue and build successfully in iOS 13.