discarded_futures

There should be no Future-returning calls in synchronous functions unless they are assigned or returned.

Making asynchronous calls in non-async functions is usually the sign of a programming error. In general these functions should be marked async and such futures should likely be awaited (as enforced by unawaited_futures).

DON'T invoke asynchronous functions in non-async blocks.

BAD:

void recreateDir(String path) {
  deleteDir(path);
  createDir(path);
}

Future<void> deleteDir(String path) async {}

Future<void> createDir(String path) async {}

GOOD:

Future<void> recreateDir(String path) async {
  await deleteDir(path);
  await createDir(path);
}

Future<void> deleteDir(String path) async {}

Future<void> createDir(String path) async {}

To enable the discarded_futures rule, add discarded_futures under linter > rules in your analysis_options.yaml file:

linter:
  rules:
    - discarded_futures

If you're instead using the YAML map syntax to configure linter rules, add discarded_futures: true under linter > rules:

linter:
  rules:
    discarded_futures: true