How to make associatedtype be a protocol?

Question

I'm struggling to implement this protocol using another protocol as its associatedtype.

I have these two:

public protocol CarToken: Any {
}

public protocol Car: AnyObject {
    associatedtype Token: CarToken

    func doThis(_ token: Token)
    func doThat(_ token: Token)
}

If I try to implement the Car like this, it works:

class ObjectThatImplementsCarToken: CarToken {
}

extension FooBar: Car {
    func doThis(_ token: ObjectThatImplementsCarToken) { ... }
    func doThat(_ token: ObjectThatImplementsCarToken) { ... }
}

But if instead I use a protocol ProtocolThatExtendsCarToken, the compiler won't accept:

protocol ProtocolThatExtendsCarToken: CarToken {
}

// Error:
extension FooBar: Car {
    func doThis(_ token: ProtocolThatExtendsCarToken) { ... }
    func doThat(_ token: ProtocolThatExtendsCarToken) { ... }
}

The compiler thinks FooBar doesn't conform to Car.

Why is that? I want those functions to accept multiple types that implements ProtocolThatExtendsCarToken, which by extension they all implement CarToken. Is that possible?