Making a claim that something will never be the case can feel like an invitation for the universe to prove otherwise. Fortunately for us, Swift lives up to this higher standard thanks to the unlikeliest of types.

11:37 AM

Result<String, Never>だとswitchでcase . failure書かなくても良いのか。 @swift-main

import Foundation enum Result<Value, Error: Swift.Error> { case success(Value) case failure(Error) } func alwaysSucceeds(_ completion: (Result<String, Never>) -> Void) { completion(.success("yes!")) } alwaysSucceeds { (result) in switch result { case .success(let string): print(string) } }