dart doc not generating documentation for sub folders?

"dart doc ." (or "dart doc") command is generation docs but only for everything in lib folder not sub folders. I have a src folder in lib which have other sub folders [lib > src > models > my_modal.dart] but after running command html is only generated for main.dart file (and a config.dart file in config folder [lib > config > config.dart])

here is my dart file

import 'package:photo_qc/src/screens/login_page.dart';

// common imports
import 'package:photo_qc/src/utils/common.dart';

/// App starts here at [main]
void main() async {
  /// Insures all widget bootstrapping
  WidgetsFlutterBinding.ensureInitialized();

  /// Creates HiveDB if not exists at [path]
  ///
  /// Links it with bloc architecture
  final Storage storage = await HydratedStorage.build(
    storageDirectory: await getApplicationDocumentsDirectory(),
  );

  /// Starts app
  ///
  /// Everything in [runZone] can access [HydratedBloc]
  HydratedBlocOverrides.runZoned(
    () => runApp(const LoginPage()),
    storage: storage,
  );
}

And here is my folder structure

1. lib > main.dart
2. lib > src > model > wall_model.dart
3. lib > src > widgets > some.dart

My docs are as per Effective Dart guidelines and "dart analyse" (or "flutter analyse" ) commands giving 0 issues.

Here is a GitHub issue for the same.

Dartdoc-issue