Swift Concurrency
Resolve Swift concurrency compiler errors, adopt approachable concurrency (SE-0466)...
Install
npx skills add dpearson2699/swift-ios-skills --skill swift-concurrency -g -a claude-code -y- Repository
- dpearson2699/swift-ios-skills1.3k
- Category
- Design
- Updated
- 3mo ago
- License
- See repository
- Context cost
- Mediumabout 3,000 tokens
- Runs scripts
- No, instructions only
What it does
Resolve Swift concurrency compiler errors, adopt approachable concurrency (SE-0466), and write data-race-safe async code. Use when fixing Sendable conformance errors, actor isolation warnings, or strict concurrency diagnostics; when adopting default MainActor isolation, @concurrent, nonisolated(nonsending), or Task.immediate; when designing actor-based architectures, structured concurrency with TaskGroup, or background work offloading; or when migrating from @preconcurrency to full Swift 6 strict concurrency.
Swift Concurrency
Review, fix, and write concurrent Swift code targeting Swift 6.3+. Gate Swift 6.4 / Xcode 27 beta cleanup APIs behind explicit toolchain and availability checks. Apply actor isolation, Sendable safety, and modern concurrency patterns with minimal behavior changes.
Contents
- Triage Workflow
- Swift 6.2 Language Changes
- Actor Isolation Rules
- Sendable Rules
- Structured Concurrency Patterns
- Task Cancellation
- Actor Reentrancy
- AsyncSequence and AsyncStream
@Observable and Concurrency- Synchronization Primitives
- Common Mistakes
- Review Checklist
- References
Triage Workflow
When diagnosing a concurrency issue, follow this sequence:
Step 1: Capture context
- Copy the exact compiler diagnostic(s) and the offending symbol(s).
- Identify the project's concurrency settings:
- Swift language version (must be 6.2+).
- Xcode/toolchain version for version-specific features and release-note workarounds.
- Whether Approachable Concurrency is enabled.
- Whether Default Actor Isolation is set to
MainActor. - Swift 6 strict concurrency status: complete/errors in Swift 6 language mode; Complete / Targeted / Minimal only when auditing Swift 5 migration settings.
- Determine the current actor context of the code (
@MainActor, customactor,nonisolated) and whether a default isolation mode is active. - Confirm whether the code is UI-bound or intended to run off the main actor.
Step 2: Apply the smallest safe fix
Prefer edits that preserve existing behavior while satisfying data-race safety.
