avoid-redundant-async

added in: 1.0.0 warning

Checks for redundant async in a method or function body.

Cases where async is useful include:

• The function body has await.
• An error is returned asynchronously. async and then throw is shorter than return Future.error(...).
• A value is returned and it will be implicitly wrapped in a future. async is shorter than Future.value(...).

Additional resources:

• https://dart.dev/guides/language/effective-dart/usage#dont-use-async-when-it-has-no-useful-effect

Example

Bad:

Future<void> afterTwoThings(Future<void> first, Future<void> second) async {
  return Future.wait([first, second]);
}

Good:

Future<void> usesAwait(Future<String> later) async {
  print(await later);
}

Future<void> asyncError() async {
  throw 'Error!';
}

Future<void> asyncValue() async => 'value';