Iceman

@swift-6.0.3 @swift-5.10.1

actor A { var stored = 0 var fooHandler: ((isolated A, _ value: String) -> Int)? func foo(value: String) -> Int { if let fooHandler { return fooHandler(self, value) } return 0 } } func withActor<A: Actor>(_ `actor`: isolated A, _ run: (isolated A) -> ()) { run(`actor`) } extension Actor { @discardableResult func apply(_ run: (isolated Self) -> Void) -> Self { run(self) return self } } func f() async { let a = A() await withActor(a) { $0.fooHandler = { (self, arg0) in return /* withActor */ self.stored } } await a.apply { $0.fooHandler = { (self, arg0) in return /* apply */ self.stored } } }

(edited)

exit status: 1 with

<stdin>:29:41: error: actor-isolated property 'stored' can not be referenced from a nonisolated context 1 | actor A { 2 | var stored = 0 | `- note: property declared here 3 | 4 | var fooHandler: ((isolated A, _ value: String) -> Int)? : 27 | await withActor(a) { 28 | $0.fooHandler = { (self, arg0) in 29 | return /* withActor */ self.stored | `- error: actor-isolated property 'stored' can not be referenced from a nonisolated context 30 | } 31 | }

(edited)