If people make extraordinary claims, I expect extraordinary proofs…
Also, there is nothing complex in a C compiler. As students we built these things as toy projects at uni, without any knowledge of software development practices.
Yet, to bring an example for something that's more than a toy project: 1 person coded this video editor with AI help: https://github.com/Sportinger/MasterSelects
From the linked project:
> The reality: 3 weeks in, ~50 hours of coding, and I'm mass-producing features faster than I can stabilize them. Things break. A lot. But when it works, it works.