struct Test: Identifiable vs class Test: Identifiable

Question

struct Test: Identifiable {}

causes the error: \"Type \'Test\' does not conform to protocol \'Identifiable\'\".
It wants \"id\" property.

Answer 1

From SE-0261 Identifiable Protocol (emphasis mine):

In order to make it as convenient as possible to conform to Identifiable, a default id is provided for all class instances:

extension Identifiable where Self: AnyObject {
    var id: ObjectIdentifier {
        return ObjectIdentifier(self)
    }
}

Then, a class whose instances are identified by their object identities need not explicitly provide an id:

final class Contact: Identifiable {
    var name: String

    init(name: String) {
        self.name = name
    }
}