library_annotations

This annotation should be attached to a library directive.

The analyzer produces this diagnostic when an annotation that applies to a whole library isn't associated with a library directive.

The following code produces this diagnostic because the TestOn annotation, which applies to the whole library, is associated with an import directive rather than a library directive:

@TestOn('browser')

import 'package:test/test.dart';

void main() {}

Associate the annotation with a library directive, adding one if necessary:

@TestOn('browser')
library;

import 'package:test/test.dart';

void main() {}