One more question: can you transform FIR? Or can y...

# compiler

[Caleb B]

One more question: can you transform FIR? Or can you only run transformers on IR? I'm working on Spring-like composite annotations now, and I'm gathering a lot of information in FIR for diagnostics that I'm having to immediately throw out and regather in IR. It would be a lot easier if I could just change the annotations on a declaration in FIR instead.

[Youssef Shoaib [MOD]]

You're not supposed to, but you can. I've had success transforming function bodies in a status transformer.
What you likely want though is to communicate between your FIR and IR extensions. You can easily do that by passing some mutable map between them.