Thanks for asking! The core of the compiler should be close to 50k LoC, with most of the rest being tests. The project is much older than git history suggests - I started a fresh repository for the initial release after several months of experiments and false starts to find the right direction. LLMs certainly helped e.g. with mechanical tasks like generating tests and refactors where changes cascaded throughout the pipeline, and I also relied on them to understand Hindley-Milner type inference, Lindig for the formatter, and Maranget for exhaustiveness checking.
These things are so common that r/programminglanguages had to ban them, because they were being posted constantly. So my concern is: what differentiates your project from the sea of others exactly like it, which as I've been following them? Usually the main dev grows bored with it quickly when the agent starts having trouble building features and the project is silently abandoned.