The issue is that the Claude's C Compiler repository does not explicitly identify the project as a proof of concept. It was largely produced by one person directing Claude, and Bun's Rust rewrite also seems to have been driven by roughly one person using Claude Code. That similarity is what worries me. Bun's rewrite could also turn out to be proof of concept.
I guess I'm debating, but it seemed clear enough to me? It proved that AI models and their harnesses are to the point where you can give them some work to do and leave them unattended for a long time, and they'll keep doing productive work for quite a while. This was a novel thing, and quite unclear, at the time the experiment was performed.
Obviously, the word "productive" is doing a lot of work there, but in my understanding the intention was nowhere near "commercially viable" or "practically useful", it was more like "not doing stupid shit like writing comments of the form 'This file contains the implementation implementation implementation implementation implementation implementation implementation implementation implementation implementation implementation implementation implementation ...'".
Maybe somewhere in the vicinity of "either passing more tests or generating more valid tests"?