Anyone see a flaw or potential snags with this attack?
Co-routines that call co-routines are where it gets tricky for the algorithm you outlined. Consider this line in your example:
yield { $self->{left}->next_inorder } if $self->{left};
next_inorder is called recursively, and the context of yielding a yielded result should leave the execution within the recursive call to next_inorder.
You could make this example work by differentiating between a yielded result and a normal return. However, once you have code that has side effects it starts getting hard.
