What's new in Swift - WWDC25 - Videos - Apple Developer

Previously, in order to build your projects, Swift PM first had to fetch the sources of swift-syntax, which is a library that powers macros. Then it would build swift-syntax, build the Stringify macro plugin, and finally build your code. While the build of swift-syntax could be cached, it still lengthened the time needed to perform a clean build. … And even when the notification is guaranteed to be posted on the main thread, you’d still get concurrency errors when accessing main actor APIs. Notification names and payloads now support concrete types. Concrete types allow the compiler to check that the object supports the notification kind you’re registering for. They also eliminate boilerplate when working with the notification payload.