> Could've sworn I've read somewhere the Rust maintainers stated that Rust will never have a switch to disable bounds checking. Has this changed?

Not having a switch to disable bounds checking is not the same as not being able to disable bounds checking.

> I don't know of any other specifics, but benchmarks usually show D outperform Rust (and often enough, everything else), e.g.:

It's been years since I saw those benchmarks. Those are benchmarks of the built-in library random number generator. Rust uses a more secure random number generator by default than most of the other languages, so it will go slower. If you really want to benchmark random number generation, pick a faster but less secure algorithm.