# 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. ## Relationships ### Conforms To [`DynamicInstructions`](/documentation/FoundationModels/DynamicInstructions) [`Content`](/documentation/CoreMedia/CMSampleBuffer/Content) [`SendableMetatype`](/documentation/Swift/SendableMetatype) [`CustomHoverEffect`](/documentation/SwiftUI/CustomHoverEffect) [`AtomicRepresentable`](/documentation/Synchronization/AtomicRepresentable) [`ControlWidgetConfiguration`](/documentation/SwiftUI/ControlWidgetConfiguration) [`Generable`](/documentation/FoundationModels/Generable) [`AxisMark`](/documentation/Charts/AxisMark) [`Chart3DContent`](/documentation/Charts/Chart3DContent) [`ShapeStyle`](/documentation/SwiftUI/ShapeStyle) [`MapContent`](/documentation/MapKit/MapContent) [`SortComparator`](/documentation/Foundation/SortComparator) [`CoordinateSpace3D`](/documentation/Spatial/CoordinateSpace3D) [`AppExtensionScene`](/documentation/ExtensionKit/AppExtensionScene) [`ImmersiveSpaceContent`](/documentation/SwiftUI/ImmersiveSpaceContent) [`AttachmentContent`](/documentation/RealityKit/AttachmentContent) [`SceneAccessoryContent`](/documentation/SwiftUI/SceneAccessoryContent) [`Plottable`](/documentation/Charts/Plottable) [`View`](/documentation/SwiftUI/View) [`Decodable`](/documentation/Swift/Decodable) [`ParameterSummary`](/documentation/AppIntents/ParameterSummary) [`Scene`](/documentation/SwiftUI/Scene) [`Transferable`](/documentation/CoreTransferable/Transferable) [`Hashable`](/documentation/Swift/Hashable) [`TableRowContent`](/documentation/SwiftUI/TableRowContent) [`TransferRepresentation`](/documentation/CoreTransferable/TransferRepresentation) [`Equatable`](/documentation/Swift/Equatable) [`ConvertibleFromGeneratedContent`](/documentation/FoundationModels/ConvertibleFromGeneratedContent) [`WidgetConfiguration`](/documentation/SwiftUI/WidgetConfiguration) [`Escapable`](/documentation/Swift/Escapable) [`CoordinateSpace3DFloat`](/documentation/Spatial/CoordinateSpace3DFloat) [`IntentValueConvertible`](/documentation/AppIntents/IntentValueConvertible) [`Commands`](/documentation/SwiftUI/Commands) [`Error`](/documentation/Swift/Error) [`CompositorContent`](/documentation/SwiftUI/CompositorContent) [`ToolbarContent`](/documentation/SwiftUI/ToolbarContent) [`ChartContent`](/documentation/Charts/ChartContent) [`ReportableMetadata`](/documentation/StateReporting/ReportableMetadata) [`InstructionsRepresentable`](/documentation/FoundationModels/InstructionsRepresentable) [`PromptRepresentable`](/documentation/FoundationModels/PromptRepresentable) [`AxisContent`](/documentation/Charts/AxisContent) [`Copyable`](/documentation/Swift/Copyable) [`PrimitivePlottableProtocol`](/documentation/Charts/PrimitivePlottableProtocol) [`BitwiseCopyable`](/documentation/Swift/BitwiseCopyable) [`ControlWidgetTemplate`](/documentation/SwiftUI/ControlWidgetTemplate) [`Comparable`](/documentation/Swift/Comparable) [`MapSelectable`](/documentation/MapKit/MapSelectable) [`CustomizableToolbarContent`](/documentation/SwiftUI/CustomizableToolbarContent) [`Gesture`](/documentation/SwiftUI/Gesture) [`Encodable`](/documentation/Swift/Encodable) [`PersistentlyIdentifiable`](/documentation/AppIntents/PersistentlyIdentifiable) [`IntentResult`](/documentation/AppIntents/IntentResult) [`Identifiable`](/documentation/Swift/Identifiable) [`DynamicProfile`](/documentation/FoundationModels/LanguageModelSession/DynamicProfile) [`TestScoping`](/documentation/Testing/TestScoping) [`AppIntent`](/documentation/AppIntents/AppIntent) [`ConvertibleToGeneratedContent`](/documentation/FoundationModels/ConvertibleToGeneratedContent) [`IntentValueExpressing`](/documentation/AppIntents/IntentValueExpressing) [`StoreContent`](/documentation/StoreKit/StoreContent) [`Sendable`](/documentation/Swift/Sendable) [`Keyframes`](/documentation/SwiftUI/Keyframes) [`AccessibilityRotorContent`](/documentation/SwiftUI/AccessibilityRotorContent) [`TableColumnContent`](/documentation/SwiftUI/TableColumnContent) --- Copyright © 2026 Apple Inc. 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