# prefer_void_to_null

> Details about the prefer_void_to_null diagnostic produced by the Dart analyzer.



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_Unnecessary use of the type 'Null'._

## Description

The analyzer produces this diagnostic when `Null` is used in a location
where `void` would be a valid choice.

## Example

The following code produces this diagnostic because the function `f` is
declared to return `null` (at some future time):

```dart
Future<[!Null!]> f() async {}
```

## Common fixes

Replace the use of `Null` with a use of `void`:

```dart
Future<void> f() async {}
```

