[0x457]

> Fast Rust demands considerably more thoughtfulness from the programmer (at least for me).

While fast code requires thoughtfulness regardless of the language, I think rust lets you focus on the fast aspect more because rustc ensures _some_ safety and correctness.

I can write fast and very unsafe C code fast, but I write code that just as fast , but safer in rust faster than in C.

[AlotOfReading]

It's entirely likely that you could write faster Rust in the same (nigh-infinite) time it'd take to write equally safe C. I intentionally avoided that comparison though. If you take a normal 10min function in C, it's going to compile into something reasonable and run fast. If you take the same 10min rust function, the language surface area is so much larger that there's a much higher chance that it won't.

Here's a more concrete, albeit irrelevant in practice example from writing most things in both languages:

https://news.ycombinator.com/item?id=42342382#42352053

Implemented in Rust over generic T, you need Wrapping<T> or the equivalent num_traits traits. The implementations for these take borrowed references. Rustc is pretty good at ensuring this becomes pass by value under the hood, but it's imperfect. I found instances of it failing in the test disassembly, even though an implementation for this never has to touch anything but registers. That's performance work that wouldn't have existed in C/C++ for these particular types.