What I do for these situations is do the reflection as a unit test to confirm that the hand written children() is correct. When the unit test fails for a node

What I do for these situations is do the reflection as a unit test to confirm that the hand written children() is correct. When the unit test fails for a node type it prints what it should be and you just copy and paste that code for children() should be. This is also nice for the case where nodes have some sort special children(). You can make the unit test ignore those.