What's new in this year's Xcode?

This year's Xcode, specifically Xcode 16, introduces several exciting new features and improvements across various aspects 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. (What’s new in Xcode 16)

2. Swift 6:

   • Swift 6 introduces a new language mode that provides concurrency safety guarantees, turning data races into compile-time issues, which improves the correctness and safety of your code. (What’s new in Xcode 16)

3. Previews:

   • Xcode Previews now use a new dynamic linking architecture that avoids rebuilding your project when switching between previews and builds, making the workflow smoother and more productive. A new previewable macro allows the use of dynamic properties like state directly in an Xcode preview. (Platforms State of the Union)

4. Builds:

   • 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 on by default, while for Swift, you need to opt-in. (What’s new in Xcode 16)

5. Debugging and Performance:

   • The thread performance checker now surfaces issues like main thread hangs, priority inversions, excessive disk writes, and slow app launches. The organizer now includes a new category of diagnostic logs for app launches, showing the slowest code path signatures to help prioritize fixing issues. (What’s new in Xcode 16)

6. Generative Tools:

   • Xcode 16 integrates generative models to enhance tools like code completion. The new engine can predict the code you need, using project symbols to customize suggestions, and it runs locally on your Mac. (Platforms State of the Union)

7. SwiftAssist:

   • SwiftAssist is a new companion for coding tasks that can answer coding questions and help with code generation, running in the cloud to leverage a larger and more powerful model. (Platforms State of the Union)

8. Flame Graphs:

   • Instruments now include flame graphs for profiling data, providing a visual way to see call stacks and identify performance issues. (What’s new in Xcode 16)

For a more detailed overview, you can watch the full session on What’s new in Xcode 16.