[afiori]

I am neither a lawyer nor experienced with anything serious, but accordingly to how copyright is often a relevant topic in this "everyone is creator" era I believe that to be derivative you need to change the purpose.

rewriting the parser to make a background image for a desktop could be derivative as being "artistic" is not anywhere near the intention of the original creation. So the picture could be MIT and the code the picture shows GPL.

In general how you use something is more relevant than how you produce something. A human translation with heavy restructuring of the code and improvements can be derivative (maybe) putting it inside a pipeline (be it a transpiler or a contractor) wouldn't.