Now x is 3 but you also get a compiler warning telling you not to do that.

In my opinion it's a bit disingenuous to argue that it isn't a const just because you can ignore the compiler and shoot yourself in the foot. If you listen to the compiler, it is reflected in the assembly that it is a constant value the same as #define x 2.

Is Rust better at enforcing guarantees? Of course. Is `const` in C `const` if you don't ignore compiler warnings and errors? Also of course.

> And since I paid for the place where I'm writing this with cash earned writing C a decade or so ago

Ditto!