swift-63-modernization

name	swift-63-modernization
description	Use when writing, reviewing, migrating, or debugging Swift 6.3 code, especially strict concurrency, Sendable, actors, SwiftPM, Swift Testing, macros, and Apple-platform builds.

Swift 6.3 Modernization

Treat Swift 6.3 as active only when swift --version, Package.swift, Xcode settings, or CI confirms the toolchain.

Focus on strict concurrency: Sendable values across task boundaries, actor or lock isolation for mutable shared state, @MainActor for UI state, and @Sendable escaping concurrent closures. Prefer fixing isolation over suppressing diagnostics with @unchecked Sendable, nonisolated(unsafe), or @preconcurrency.

Use project commands (swift test, swift build, xcodebuild) and only set swift-tools-version: 6.3 when local and CI toolchains support it.