Considering the number of provers and statistical analysers and given C is the only mainstream language with a formally verified compiler, I would say fairly well thank you.

Honestly, I am not even opposed to Rust. It has cool ideas. I do think it should care a lot more about being portable and properly defined and should have done so a lot earlier and I do deeply disagree with the opinion of some core team members that specification is meaningless.

C obviously always was a questionable choice for a tool like apt but Rust seems even worse to me. Apt has absolutely no need to be written in a low level language. At least you could argue that C was chosen because it’s portable but I don’t see what Rust has going for it.

All those things didn’t stop Heartbleed or numerous other CVEs from happening, though, did it?

Doesn't Java have also a formally verified compiler?