Swift 6 | Ask WWDC

Swift 6 was a significant focus at WWDC 2024, bringing numerous enhancements to the Swift programming language. Here are some key highlights:

Data Race Safety: Swift 6 introduces a new language mode that provides compile-time data race safety, making concurrent programming easier and safer. This mode is opt-in, allowing developers to adopt it module by module and interoperate with dependencies that may not have migrated yet. This feature helps diagnose concurrent access to memory and fix data race safety errors with minimal code changes (Platforms State of the Union).
Non-Copyable Types: Swift 6 introduces non-copyable types, which are types that cannot be copied. This feature is useful for managing resources more efficiently and ensuring that certain types of data are not inadvertently duplicated (What’s new in Swift).
Embedded Swift: A new subset of Swift called Embedded Swift is introduced, targeting highly constrained environments like operating system kernels and microcontrollers. This makes Swift a viable option for a broader range of applications (What’s new in Swift).
Swift Testing: An all-new testing framework named Swift Testing has been built from the ground up for Swift. It features expressive APIs that simplify writing tests and is designed to integrate seamlessly with Swift's concurrency model (Platforms State of the Union).
Concurrency Improvements: Swift 6 continues to build on the concurrency model introduced in previous versions, with enhancements to async/await, structured concurrency, and actors. These improvements further streamline writing concurrent code and ensure better performance and safety (What’s new in Swift).
Swift Data Enhancements: Swift Data has been improved with new syntax additions like index and unique, which make queries more efficient and ensure data integrity. The new previewable macro also enhances the development experience by making it easier to work with queries while iterating on views (Platforms State of the Union).

For a detailed overview of these features and more, you can watch the session What’s new in Swift.