prefer_void_to_null

Unnecessary use of the type 'Null'.

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

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

Future<Null> f() async {}

Replace the use of Null with a use of void:

Future<void> f() async {}

Unless stated otherwise, the documentation on this site reflects Dart 3.7.3. Page last updated on 2025-05-08. View source or report an issue.