Swift 6.2: A first look at how it's changing Concurrency

a year ago

Swift 6.2 is the upcoming release of Apple’s native language, currently in active development.
Swift 6 has been released, but many developers struggle with migration, especially with concurrency.
The Swift team published a vision document in February 2025 to improve data-race safety and approachability.
Three phases for progressive disclosure of concurrency: simple single-threaded code, async code without data-race safety errors, and advanced concurrency.
Swift 6.2 will include changes to reduce compiler warnings and errors, with plans for automatic migration.
Key proposals being implemented in Swift 6.2 include SE-0371, SE-0461, SE-0463, SE-0466, and SE-0470.
SE-0466 introduces a new compiler setting for inferring @MainActor isolation by default to mitigate false-positive data-race safety errors.
SE-0461 changes how nonisolated async functions are evaluated, making them inherit the caller’s actor isolation by default.
Swift Concurrency improvements aim to make the language more approachable for beginners and easier to adopt for existing projects.
Developers are encouraged to invest in concurrency knowledge, with resources like the Essential Swift Concurrency Course available.

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