omochimetaru

@swift-5.10.1 @swift-6.0.3 @swift-main -strict-concurrency=complete

@propertyWrapper struct W<T> { var wrappedValue: T { fatalError() } } extension W: Sendable where T: Sendable {} struct K: Sendable { init() {} func hi() {} } // 間違った警告が出る func main1() async throws { @W var k: K Task { k.hi() } k.hi() } // 本質的に以下と等価なはず // これだと警告は出ない func main2() async throws { let k: W<K> = .init() Task { k.wrappedValue.hi() } k.wrappedValue.hi() }

(edited)

<stdin>:17:5: warning: value of non-Sendable type '@isolated(any) @async @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <()>' accessed after being transferred; later accesses could race; this is an error in the Swift 6 language mode 15 | @W var k: K 16 | 17 | Task { | `- warning: value of non-Sendable type '@isolated(any) @async @callee_guaranteed @substituted <τ_0_0> () -> @out τ_0_0 for <()>' accessed after being transferred; later accesses could race; this is an error in the Swift 6 language mode 18 | k.hi() 19 | } 20 | 21 | k.hi() | `- note: access can happen concurrently 22 | } 23 |