anchor.diff:      }
       if (_providerChanges != null) {
         if (_observers != null) {
  +        // changes is immutable as if observers modified it, the behavior
  +        // would be unpredictable.
           final changes = UnmodifiableMapView(_providerChanges);
           for (final observer in _observers) {
             _runUnaryGuarded(
  
positive.code:     _updateScheduled = false;
    }
  
    void _reportChanged(ProviderBase origin, Object state) {
      if (_observers != null && _observers.isNotEmpty) {
        _providerChanges ??= {};
  
negative.code:     }
    }
  
    /// Call [ProviderStateBase.notifyListeners] on all providers that want to emit
    /// updates, order from providers with no dependencies to providers that depends
    /// on the entire application.
    ///
    /// This does not call the listeners of a specific provider.
    /// That is done by [ProviderStateBase.notifyListeners], which may decide not to.
    /// An example is `Computed`, which will re-execute its `selector` but not
    /// notify its listeners if the selected value didn't change.
    void _notifyListeners() {
      for (final entry in _providerStatesSortedByDepth) {
        if (entry.value._dirty) {
  