Is this isolation/concurrency error correct?

Using Swift
1

I flipped Swift 6 on and I'm getting the following error, which I'm pretty sure is incorrect, since the type in question is Sendable. What should I do?

// Sending main actor-isolated 'toast' to actor-isolated instance method 'eat(toast:)' risks causing data races between actor-isolated and main actor-isolated uses

struct Toast: Sendable {}

actor Person {
    func eat(toast: Toast) {}
}

@MainActor
final class Toaster {
    func makeToast() -> Toast {
        Toast()
    }
}


@MainActor
func test() async {
    
    let person = Person()
    let toaster = Toaster()
        
    let toast = toaster.makeToast()
    
//    // If I use var, there is no error.
//    var toast = toaster.makeToast()

    // Sending main actor-isolated 'toast' to actor-isolated instance method 'eat(toast:)' risks causing data races between actor-isolated and main actor-isolated uses
    //
    // 😕...Toast is a Sendable type, how could sending it anywhere risk causing data races?
    
    // If I create Toast right here directly, there is no error:
    // let toast = Toast()
    
    await person.eat(toast: toast)
}
2

Nevermind, fixed in Xcode 16 beta 5 (I was getting this with beta 4).

Anyway, maybe someone will stumble on this post and realize they need to update :slight_smile: