Directionality widget does not set directionality on SemanticsNode. A workaround is to wrap the Directionality widget in a Semantics widget with textDirection set accordingly. However, this is not always possible. For example, WidgetsApp sets Directionality for you, and it doesn't give you a chance to inject a Semantics widget. Another issue is that the additional Semantics widget will cause a new SemanticsNode to be inserted in the tree. It would be desirable that the effect of Directionality is a simple flip of the textDirection field on the nearest parent SemanticsNode.

/cc @goderbauer