> If a LLM can transcode correctly, then it should also output 100% correct C code.

Well LLM's cannot transcode perfectly correctly, so the fact that Rust has lots of static checking is really important. Not just for memory safety - Rust helps with many other classes of bugs too.

> then using Rust may just make the bug soundless, because the language runtime/code-gen "avoided" usual punishments that might make the bug (and bug report) obvious.

I think what you're saying here is that LLM's often cheat to solve the immediate error, e.g. by using `unsafe` where you really shouldn't, or just making a test not test anything. That's definitely possible.