What's the difference between a protocol extended from AnyObject and a class-only protocol?

Question

Both this declaration

protocol SomeProtocol : AnyObject {
}

and this declaration

protocol SomeProtocol : class {
}
<         


        

Answer 1

In the Swift programming language guide for protocols, under the Class-Only Protocols section. It only mentioned AnyObject, but not class.

You can limit protocol adoption to class types (and not structures or enumerations) by adding the AnyObject protocol to a protocol’s inheritance list.

protocol SomeClassOnlyProtocol: AnyObject, SomeInheritedProtocol {
    // class-only protocol definition goes here
}

For that reason, I will suggest using AnyObject over class for new code or new project. Other than that, I don't see any obvious difference between them.