---
title: Failure
framework: Swift
role: symbol
role_heading: Associated Type
platforms: [iOS 27.0+, iPadOS 27.0+, Mac Catalyst 27.0+, macOS 27.0+, tvOS 27.0+, visionOS 27.0+, watchOS 27.0+]
path: swift/iterable/failure
---

# Failure

## Declaration

```swift
associatedtype Failure = Never where Self.Failure == Self.BorrowingIterator.Failure
```