[kibwen]

If so, then it should be trivial for someone to introduce something like Rust's `unsafe` keyword in C such that the unsafe operations can be explicitly annotated and encapsulated.

Of course, it's not actually this trivial because what you're saying is incorrect. C is not equipped to enforce memory safety; even mundane C code is thoroughly suffused with operations that threaten to spiral off the rails into undefined behavior.

[uecker]

It is not so hard to introduce a "safe" keyword in C. I have a patched GCC that does it. The subset of the language which can be used safety is a bit too small to be full replacement on its own, but also not that small.