The protocol to which all class types implicitly conform.

    typealias AnyClass = AnyObject.Type


    You can use the AnyClass protocol as the concrete type for an instance of any class. When you do, all known @objc class methods and properties are available as implicitly unwrapped optional methods and properties, respectively. For example:

    class IntegerRef {
        @objc class func getDefaultValue() -> Int {
            return 42
    func getDefaultValue(_ c: AnyClass) -> Int? {
        return c.getDefaultValue?()

    The getDefaultValue(_:) function uses optional chaining to safely call the implicitly unwrapped class method on c. Calling the function with different class types shows how the getDefaultValue() class method is only conditionally available.

    // Prints "Optional(42)"
    // Prints "nil"