duplicates:

• SR-6816 Let protocols inherit from class types

relates to:

• SR-6816 Let protocols inherit from class types

Issue Description:

import Foundation

protocol SomeProtocol where Self: NSObject {
    func doSomething()
}
class SomeClass: NSObject, SomeProtocol {
    func doSomething() {
        print("did something!")
    }
}

let originalObject = SomeClass()
originalObject.doSomething()

let protocolCast: SomeProtocol = originalObject
protocolCast.doSomething()

The first call to doSomething() works but the second call will crash. Code compiles without error but throws a unrecognized selector exception at runtime. Removing the where clause on the protocol or adding @objc to the protocol fixes the issue.