Comment by alphanullmeric

You can do any rust optimization yourself in C++ (ie. aliasing assumptions), whereas rust makes the other way around very difficult, often forcing you to use multiple layers of indirection where c++ would allow a raw pointer, or forcing an unwrap on something you know is infallible when exceptions would add no overhead, etc. Rust programmers want people to believe that whatever appeases the supposedly zero cost borrow checker is the fastest thing to do even though it has proven to be wrong time and time again. I can’t tell you how many times I’ve seen r/rust pull the “well why do you want to do that” or “are you sure it even matters” card every time rust doesn’t allow you to write optimized code.