Template being called twice with Nim 2.0

[PMunch]

Have you double checked that the `spec: untyped` argument has the same AST as 
in pre-2.0? Just looking at the code I see that if it has two nodes it would 
run `pop` twice. So if some AST representation changed between 1.6.14 and 2.0.0 
this could be the culprit (I've had similar issues before). I guess you have 
that `debugEcho` in there though, so maybe that's not it.