What’s new in Xcode

What’s New in Xcode 16

Xcode 16 introduces several new features and improvements aimed at enhancing the development experience across various stages of app development. Here are some of the key updates:

1. Code Completion:

   • Xcode 16 features a new code completion engine powered by an on-device coding model specifically trained for Swift and Apple SDKs. This engine uses surrounding code context, such as function names and comments, to provide more thorough code suggestions. This is made possible by Apple silicon and is available when running Xcode 16 on macOS Sequoia.
   • The new predictive completion engine can predict the code you need, using your project symbols to customize suggestions. It runs locally on your Mac, ensuring your code remains private and providing super-fast results, even when offline.

2. Swift 6:

   • Swift 6 introduces a new language mode that provides concurrency safety guarantees, turning data races that are typically experienced at runtime into compile-time issues. This improves the correctness and safety of your code.

3. Xcode Previews:

   • Xcode Previews now use a new dynamic linking architecture that employs the same build artifacts for 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.
   • A new @Previewable macro allows the use of dynamic properties like state directly in an Xcode preview, reducing the amount of code you need to write.

4. Build Improvements:

   • Xcode 16 introduces explicit modules, which provide improved parallelism, better diagnostics, and faster debugging without changing a single line of code. For C and Objective-C, explicit modules are enabled by default, while for Swift, you need to opt-in.
   • The build system has been enhanced to supercharge builds with explicit modules, improving parallelism and diagnostics.

5. Debugging and Performance:

   • The thread performance checker now shows excessive disk write and slow app launch diagnostics to help improve app performance. It also surfaces the worst runtime issues, pinpointing the exact code paths that need attention.
   • The organizer now includes a new category of diagnostic logs for app launches, showing the slowest code path signatures to help prioritize fixing issues with the largest impact.

6. Instruments and Profiling:

   • Xcode 16 introduces a flame graph for profiling data in Instruments, providing deeper insight into your app's performance. This visual representation helps in identifying performance bottlenecks and optimizing code.

7. SwiftAssist:

   • SwiftAssist is a new feature that acts as a companion for all your coding tasks. It can answer coding questions, provide code suggestions, and help with various development tasks, all while ensuring your code remains private and secure.

For more detailed information, you can refer to the following sessions from WWDC 2024:

• What’s new in Xcode 16
• Platforms State of the Union

Relevant Sessions

1. What’s new in Xcode 16
2. Platforms State of the Union
3. Xcode essentials