---
title: AsyncFlatMapSequence.Failure
framework: swift
role: symbol
role_heading: Type Alias
path: swift/asyncflatmapsequence/failure
---

# AsyncFlatMapSequence.Failure

The type of error produced by this asynchronous sequence.

## Declaration

```swift
typealias Failure = Base.Failure
```

## Discussion

Discussion The flat map sequence produces the type of error in the base asynchronous sequence. By construction, the sequence produced by the transform closure must either produce this type of error or not produce errors at all.