Announcing Swift 6

Holly Borla from Apple's Swift Core Team announces Swift 6, bringing data-race safety from opt-in warnings to compiler-enforced guarantees. After a decade of development, Swift now targets embedded systems, servers, and performance-critical code beyond just apps.

Swift 6 represents a major evolution of Apple's programming language, expanding beyond its million-app iOS ecosystem. The release introduces memory safety for concurrent code, embedded device support, and unified cross-platform libraries. Apple's Swift team has reimplemented Foundation entirely in Swift and launched Swift Testing as a built-in testing framework.

Key Takeaways

• Data race detection now prevents concurrency bugs at compile time, not runtime
• Embedded Swift subset runs on ARM and RISC-V microcontrollers without runtime overhead
• Foundation reimplemented in Swift provides consistency across macOS, iOS, Linux, and Windows
• Swift Testing library ships in toolchain with macro-based APIs and parameterized tests
• Static Linux binaries have zero dependencies for containers and direct deployment

The new ownership system with non-copyable types and the @DebugDescription macro reveal how Swift is tackling performance at the language level.