What’s new in XCode?

Xcode 16 introduces several exciting new features and improvements to enhance the app development process. Here are some of the highlights:

Code Completion: Xcode 16 features an innovative new engine for code completion, powered by a model specifically trained for Swift and Apple SDKs. This engine uses your project symbols to customize suggestions and runs locally on your Mac, ensuring privacy and fast results. This is part of a broader effort to infuse Xcode with the power of generative models, building on Apple's foundation model.
Swift 6: The new language mode in Swift 6 provides concurrency safety guarantees, turning data races into compile-time issues, which improves the correctness and safety of your code.
Previews: Xcode Previews now have a dynamic linking architecture that uses the same build artifacts for both previews and when you build and run, avoiding the need to rebuild your project when switching between the two. This results in a smoother and more productive workflow.
Builds: Xcode 16 introduces explicit modules, which improve parallelism, diagnostics, and debugging without changing any code. For C and Objective-C, explicit modules are on by default, while for Swift, you need to opt in.
Debugging and Performance: The thread performance checker now shows excessive disk write and slow app launch diagnostics, helping you improve your app's performance. The organizer provides a new category of diagnostic logs for app launches, showing the slowest code path signatures.
Swiftassist: A new feature called Swiftassist acts as a companion for coding tasks, answering coding questions and helping with tasks like experimenting with new APIs. It is built with privacy and security in mind, ensuring your code is never stored on the server.
Instruments and Flame Graphs: Xcode 16 includes a flame graph of your profiling data in instruments, providing deeper insight into your app's performance. This visual representation helps in identifying issues and optimizing performance.

For more detailed information, you can refer to the session What’s new in Xcode 16 and Platforms State of the Union.