That's telling you that Rust has the C++ Memory Ordering rules, not that it has the C++ Forward Progress guarantee. C likewise has the C++ Memory Ordering, but

That's telling you that Rust has the C++ Memory Ordering rules, not that it has the C++ Forward Progress guarantee. C likewise has the C++ Memory Ordering, but not its Forward Progress guarantee. As I wrote earlier, C has infinite loops, they're spelled the way you'd obviously write them in C or C++, but in C they're supposed to actually work (whereas in C++ they are UB). Rust is only different here syntactically, the semantic feature is identical to C's choice.