In my opinion, the two languages are going to co-exist for a long time. C has billions of lines of legacy software written in it… In recent news, COBOL developers were sought after in order to update existing COBOL software, so the same thing will happen with C, perhaps to the end of humanity (I have become pessimistic as to humanity's future).
There are pieces of software that should be given priority for a rewrite in Rust, but most of C software is never going to be rewritten, because there is simply too much of it.
Therefore, even if C did not have any advantage of its own over Rust, there would still be legacy software to maintain and to extend.
The advantages of C include that sometimes, an embedded processor with a proprietary instruction set is provided by the chipmaker with its own C compiler, which is the only compiler supporting the instruction set; that C is still currently used to write the runtimes of higher-level languages (I'm familiar with OCaml, but it isn't too much of a stretch to imagine that the runtimes of Python, Haskell,… are also written in C).
> In my opinion, the two languages are going to co-exist for a long time.
It goes deeper than that, in a couple of places Rust depends on the C standard: the fixed-layout `#[repr(C)]` structs (without that attribute, the compiler is free to reorder the struct fields; with that attribute, it's laid out the way C would do it), and the `extern "C"` function call ABI. The way to call any other language from Rust, or Rust from any other language, is to go through `extern "C"` functions passing `#[repr(C)]` structs. So even if the C language dies one day, parts of it will live in Rust forever (or as long as the Rust language lives).
There's tons of legacy C around, we have to maintain it, it's not ideal unless you're on some niche platform, lots of stuff should probably be written in a better language . . .
I sincerely hope this is not the general attitude of the standards committee. Some of us actually prefer C, and would like to see the language continue to flourish.
Note that among the C experts participating in this AMA, I am not one who is in the standardization committee. At 14:59 EDT, just before the AMA was posted, we were joking between ourselves about me having to post this disclaimer but I guess there was a hidden truth in the joke.
C is a pretty well established language, so this question should probably be asked the other way around. C was primarily designed to complete with FORTRAN.
