Swift 6.2 Concurrency Updates

Swift 6.2 introduces "Approachable Concurrency" -- a set of changes that make strict concurrency dramatically easier to adopt. The philosophy shifts from "opt in to safety" to "safe by default, opt in to concurrency." Code runs on @MainActor by default, async functions stay on the calling actor, and you explicitly request background execution with @concurrent.

This skill covers only the Swift 6.2 specific changes. For general concurrency patterns (actors, TaskGroup, AsyncSequence, Sendable, cancellation), see the swift/concurrency-patterns skill.

When This Skill Activates

• User is adopting Swift 6.2 concurrency features
• User asks about default MainActor inference or the "infer main actor" build setting
• User encounters data-race errors that Swift 6.2 resolves
• User asks about @concurrent, isolated conformances, or approachable concurrency
• User wants to migrate from Swift 6.0/6.1 strict concurrency to 6.2
• User asks how async functions behave differently in Swift 6.2
• User needs to offload CPU-intensive work to a background thread in Swift 6.2

What Changed in Swift 6.2 vs Before

The Core Problem with Swift 6.0/6.1