Could anyone please clarify how the concurrency checking works in my case? I have an actor that calls the foo method of a @MainActor class:

actor MyActor {
    let property: MainActorClass

    init(property: MainActorClass) {
        self.property = property
    }

    func doSomething() async {
        await property.foo()
    }
}

@MainActor
class MainActorClass {
    func foo() async {
        print("foo")
    }
}

It compiles with Swift 6, but when I’m trying to abstract my MainActorClass with MainActorProtocol:

actor MyActor {
    let property: MainActorProtocol

    init(property: MainActorProtocol) {
        self.property = property
    }

    func doSomething() async {
        await property.foo()
    }
}

@MainActor
protocol MainActorProtocol {
    func foo() async
}

class MainActorClass: MainActorProtocol {
    func foo() async {
        print("foo")
    }
}

I am getting an error:
Sending ‘self.property’ risks causing data races

What’s the difference between these two approaches and how can I abstract my MainActorClass with a Protocol?

I tried to add Sendable to a Protocol but it looks a little bit cumbersome to add Sendable to almost every protocol in a project.