@swift-main @swift-5.3.3 @swift-5.2.5 @swift-5.0.3 @swift-4.2.4

import Foundation @objc public protocol C { @objc optional var field1: ObjCBool { get set } } extension C { public func set(value: Bool) { self[keyPath: \C.field1] = ObjCBool(value) } }