Not to discount your experience, but I dont understand what's interesting about this. You could always build a programming language yourself, given enough time. Programming languages' constructs are well represented in the training dataset. I want someone to build something uniquely novel that's not actually in the dataset and i'll be impressed by CC.

I find it as an interesting experiment to find the limits of what they can do.

Like, I've had it build a full APL interpreter, half an optimizer, started on a copy-and-patch JIT compiler and it completely fails at "read the spec and make sure the test suite ensures compliance". Plus some additional artifacts which are genuinely useful on their own as I now have an Automated Yak Shaver™ which is where most of my projects ended up dying as the yaks are a fun bunch to play with.