# require(_:_:sourceLocation:) Unwrap an optional value or, if it is `nil`, fail and throw an error. ``` @freestanding(expression) macro require(_ optionalValue: T?, _ comment: @autoclosure () -> Comment? = nil, sourceLocation: SourceLocation = #_sourceLocation) -> T ``` ## Parameters `optionalValue` The optional value to be unwrapped. `comment` A comment describing the expectation. `sourceLocation` The source location to which recorded expectations and issues should be attributed. ## Return Value The unwrapped value of `optionalValue`. ## Overview> Throws: An instance of ``doc://org.swift.testing/documentation/Testing/ExpectationFailedError`` if `optionalValue` is > `nil`. If `optionalValue` is `nil`, an [`Issue`](/documentation/Testing/Issue) is recorded for the test that is running in the current task and an instance of [`ExpectationFailedError`](/documentation/Testing/ExpectationFailedError) is thrown. --- 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)