No mention of Scott Nudds?
Scott Nudds was a guy who trolled comp.lang.c and a few other programming newsgroups. He was noted for his phrases "Unix and C are dying, this is a good thing." and "C pushers will do anything to defend their sick religion. I, on the other hand, prefer honesty." For a while, the usual reference to "making demons fly out of your nose" (a humorously valid potential response by the compiler when it encounters undefined behavior) was often replaced with "making Scott Nudds fly out of your nose".
Wherever you are now, Scott Nudds, you are remembered. A hero and vanguard to the Rust Evangelism Strike Force—because C really is dying now, and that's probably a good thing.
SsZERO is another, whom I've mentioned before, but his appeal was more limited:
It's not valid for a compiler to make demons fly out of your nose, since compilers are constrained by the capabilities of your hardware and the laws of physics.
Well, if a compiler were to do so it would not be in violation of the standard. Whether or not such a thing is physically possible is an implementation detail outside the scope of the standard.
The C standard isn't the only thing compilers have to comply with.
HTTP doesn't specify what happens if the request method is XYZZY. An HTTP server that confirms to the HTTP specification (but not the laws of physics) could make demons fly out of your nose when receiving a request with a method of XYZZY. But nobody complains about that.
It's a C compiler, and it's allowed to anything if it sees UB.
We can talk about C's demise after the last COBOL application is retired.
One of the reasons why Rust is taking over userland is that it's getting more and more difficult to find people willing to maintain a C code base—especially an old one—while there's no shortage of kids willing and eager to hack in Rust.
C will end up in exactly the same place as COBOL: there will be applications that depend on code written in it for decades to come, but they will be maintained by very well-paid grognards simply because those are the only people who know how, and are willing (for a steep price), to maintain them.
Maybe. I think C will continue to have relevance in certain niches like embedded development, and that efforts like Fil-C will quietly carry the torch for a long time. C will also continue to have an important role in bootstrapping.
I generally I don't like the "Rust is killing C" meme because a.) I don't believe it b.) C doesn't need to die for Rust to succeed and c.) it leads to language wars and hard feelings. Rust doesn't really do what C does; it's not a lingua franca among architectures. They compete in some niches and not others.