Unsafe actor access

Using Swift
, ,
1

Currently when migrating code to concurrency code that should be isolated to GlobalActor can be marked @preconcurrency @GlobalActor to avoid breaking existing code.

@globalActor
actor MyGlobalActor: GlobalActor {
    static let shared = MyGlobalActor()
}

@preconcurrency
@MyGlobalActor
func isolatedFunc() { }

func existingUsage() {
    // doesn't break
    isolatedFunc()
}

Is there any similar approach that can be used with classes that can be converted to actor?

@preconcurrency  // doesn't work
actor MyClass: NSObject {
    @preconcurrency // doesn't work
    var message: String
}

@preconcurrency // doesn't work
func existingUsage(obj: MyClass) {
    // breaks
    print(obj.message)
}

The only thing that I have found is the assumeisolated(_:file:line:) API. But that requires change in every call site making it not ideal for existing code that want to migrate.