The most significant new feature in Swift 6.2 is approachable concurrency, a default, low-complexity approach to writing safe concurrent applications. Swift 6.2 also introduces new features to simplify low-level programming, including the InlineArray and Span types, and adds support for WebAssembly.
Programs adopting approachable concurrency are single-threaded by default, which is ideal for scripts and UI code, and provide greater resilience for asynchronous code that accesses mutable state by running it on the caller’s executor thread. When you want to ensure an async method is run on the concurrent thread pool instead of in the caller’s context, you can use the @concurrent annotation. InfoQ previously covered approachable concurrency following its announcement at Apple’s WWDC 2025, providing additional detail and context.
Swift 6.2 also introduces two new features aimed to write safe, low-level code with predictable performance and minimal overhead. The first is InlineArray, a fixed-size array with inline storage that avoids additional heap allocation. The syntax to declare an inline array is: var inlineArray: [50 of String]. The second feature is Span, a safe alternative to buffer pointers to access contiguous memory.
Span maintains memory safety by ensuring the memory remains valid while you’re using it. These guarantees are checked at compile time with no runtime overhead, and define away the memory safety problems inherent to pointers, such as use-after-free bugs.
Another enhancement to low-level programming in Swift 6.2 is strict memory safety, an opt-in mode designed to detect unsafe constructs in a codebase, enabling developers to either replace them or explicitly acknowledge their use.
Swift 6.2 also introduces support for compiling to Wasm thanks to the new Wasm SDK.
WebAssembly support in Swift started out as a community project. Any instruction set benefits tremendously from a standardized ABI and system interfaces, and from its inception Wasm support in Swift targeted WebAssembly System Interface, which made porting Swift core libraries to this platform much easier.
The swift command line compiler can both build a Wasm executable from a Swift source file and run it using WasmKit, a standalone and embeddable WebAssembly runtime. The Wasm cross-compiler can produce significantly smaller binaries when programmers use Embedded Swift, which excludes runtime reflection, metatypes like SomeClass.Type and all standard library features that relies on it, such as Codable, non-final generic methods, weak and unowned references, and other features that increase language complexity.
Swift 6.2 includes many more enhancements that cannot be covered here, such as precise warning control based on diagnostic groups, faster macro processing, improved debugging for asynchronous code, and extended Swift Testing APIs. For full details, be sure to read the official announcement.
