yield_in_non_generator

Yield statements must be in a generator function (one marked with either 'async*' or 'sync*').

Yield-each statements must be in a generator function (one marked with either 'async*' or 'sync*').

The analyzer produces this diagnostic when a yield or yield* statement appears in a function whose body isn't marked with one of the async* or sync* modifiers.

The following code produces this diagnostic because yield is being used in a function whose body doesn't have a modifier:

Iterable<int> get digits {
  yield* [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
}

The following code produces this diagnostic because yield* is being used in a function whose body has the async modifier rather than the async* modifier:

Stream<int> get digits async {
  yield* [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
}

Add a modifier, or change the existing modifier to be either async* or sync*:

Iterable<int> get digits sync* {
  yield* [0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
}

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.