Enumeration

Never

The return type of functions that do not return normally, that is, a type with no values.

Declaration

@frozen enum Never

Overview

Use Never as the return type when declaring a closure, function, or method that unconditionally throws an error, traps, or otherwise does not terminate.

func crashAndBurn() -> Never {
    fatalError("Something very, very bad happened")
}

Topics

Instance Properties

var hashValue: Int

The hash value.

Beta

Instance Methods

func hash(into: inout Hasher)

Hashes the essential components of this value by feeding them into the given hasher.

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Operator Functions

static func != (Never, Never) -> Bool

Returns a Boolean value indicating whether two values are not equal.

static func ... (Never) -> PartialRangeFrom<Never>

Returns a partial range extending upward from a lower bound.

static func ... (Never) -> PartialRangeThrough<Never>

Returns a partial range up to, and including, its upper bound.

static func ... (Never, Never) -> ClosedRange<Never>

Returns a closed range that contains both of its bounds.

static func ..< (Never) -> PartialRangeUpTo<Never>

Returns a partial range up to, but not including, its upper bound.

static func ..< (Never, Never) -> Range<Never>

Returns a half-open range that contains its lower bound but not its upper bound.

static func < (Never, Never) -> Bool

Returns a Boolean value indicating whether the value of the first argument is less than that of the second argument.

static func <= (Never, Never) -> Bool

Returns a Boolean value indicating whether the value of the first argument is less than or equal to that of the second argument.

static func == (Never, Never) -> Bool

Returns a Boolean value indicating whether two values are equal.

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static func > (Never, Never) -> Bool

Returns a Boolean value indicating whether the value of the first argument is greater than that of the second argument.

static func >= (Never, Never) -> Bool

Returns a Boolean value indicating whether the value of the first argument is greater than or equal to that of the second argument.

See Also

Exiting a Program

func fatalError(() -> String, file: StaticString, line: UInt) -> Never

Unconditionally prints a given message and stops execution.

Beta Software

This documentation contains preliminary information about an API or technology in development. This information is subject to change, and software implemented according to this documentation should be tested with final operating system software.

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