Swift 6.4 Streamlines Daily Development, SwiftUI Gets Faster Layouts
Swift 6.4 brings targeted warning suppression, simplified availability attributes, and improved compiler diagnostics. SwiftUI gets more efficient state initialization and faster layout rendering with zero code changes.
While Xcode 27 grabbed the WWDC headlines, Swift 6.4 shipped meaningful quality-of-life improvements that affect every Apple developer's daily workflow. SwiftUI also got performance improvements that require zero code changes from developers.
Swift 6.4: what changed
- Targeted warning suppression, suppress specific warnings without disabling the entire category. Long overdue for large codebases with legacy patterns.
anyAppleOSavailability attribute, one attribute instead of listing iOS, iPadOS, macOS, watchOS, tvOS, visionOS individually.- Improved compiler diagnostics, clearer error messages and better fix-it suggestions, especially for concurrency and existential type errors.
SwiftUI performance
SwiftUI got under-the-hood improvements:
- More efficient state initialization, fewer unnecessary view body re-evaluations
- Faster layout rendering, the layout pass is optimized across the board
- Reorderable containers, built-in drag-to-reorder without custom gesture code
- Spatial Preview, stream 3D models from Mac apps to Apple Vision Pro for spatial viewing
Liquid Glass evolves
Apple's design language gets user-facing customization: a transparency slider in Settings lets users adjust the glass effect intensity. The design also adapts to accessibility settings, higher transparency when Reduce Motion is on, for example.
The bottom line
Swift 6.4 isn't a flashy release, but anyAppleOS alone will delete thousands
of lines of availability annotations from multi-platform apps. Combined with
SwiftUI's free rendering improvements, this is a "just upgrade and enjoy" release.