@swift-6.2.3 -swift-version 6
import Synchronization class C { var x = 0 } final class D: Sendable { let _c: Mutex<C?> = Mutex(C()) func getC() -> C? { _c.withLock { $0 } } } actor A { var c: C? func takeCFromD(_ d: D) { self.c = d.getC() } } func main(_ a0: A, _ a1: A, _ d: D) async { await a0.takeCFromD(d) await a1.takeCFromD(d) }