What's the point of making something like this if you don't get to deeply understand what your doing?
Ultimately though, the LLM is going to become less useful as the language grows past its capabilities. If the language author doesn’t have a sufficient map of the language and a solid plan at that point, it will be the blind leading the blind. Which is how most lang dev goes so it should all work out.
Anyway, all it will do is stop you being able to run as well as you used to be able to do when you had to go everywhere on foot.
If neither you not anyone else can fix it, without more cost than making a proper one?
In this special case, you'd have to reverse engineer the grammar from the parser, calculate first/follow sets and then see if the grammar even is what you intended it to be.
I am using LLMs to speed up coding as well, but you have to be super vigilant, and do it in a very modular way.
"Imagination is more important than knowledge."
At least for me that fits. I have quite enough graduate-level knowledge of physics, math, and computer science to rarely be stumped by a research paper or anything an LLM spits out. That may get me scorn from those tested on those subjects. Yet, I'm still an effective ignoramus.