# Never A type that has no values and can’t be constructed. ``` @frozen enum Never ``` ## Overview Use `Never` as the return type of a function that doesn’t return normally — for example, because it runs forever or terminates the program. ``` // An infinite loop never returns. func forever() -> Never { while true { print("I will print forever.") } } // Calling fatalError(_:file:line:) unconditionally stops the program. func crashAndBurn() -> Never { fatalError("Something very, very bad happened") } ``` A function that returns `Never` is called a *nonreturning* function. Closures, methods, computed properties, and subscripts can also be nonreturning. There’s no way to create an instance of `Never`; this characteristic makes it an *uninhabited* type. You can use an uninhabited type like `Never` to represent states in your program that are impossible to reach during execution. Swift’s type system uses this information — for example, to reason about control statements in cases that are known to be unreachable. ``` let favoriteNumber: Result = .success(42) switch favoriteNumber { case .success(let value): print("My favorite number is", value) } ``` In the code above, `favoriteNumber` has a failure type of `Never`, indicating that it always succeeds. The switch statement is therefore exhaustive, even though it doesn’t contain a `.failure` case, because that case could never be reached. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)