The borrowchecker is what I like the least about Rust

Post by School-Cotton » Sat, Jul 19, 2025, 8:53 PM UTC

aapoalas wrote: post #55

School-Cotton wrote: post #45

Earlier quoted context omitted.

Yes you would need an escape hatch, but your example is wrong. Vec can't be Copy, because it has a destructor. This program fails to compile: #[derive(Clone, Copy)] struct S; impl Drop for S { fn drop(&mut self) {} } fn main() {}

Actually; I'm not sure I'm wrong. If Copy was automatically derived based on fields of a struct (without the user explicitly asking for it with `#[derive(Copy)]` that is, as the parent comment suggested the OP is asking for), then your example S and the std Vec would both automatically derive Copy. Then, implementing Drop on them would become a compile error that you would have to silence by using the escape hatch to…

Post by isodev » Sat, Jul 19, 2025, 8:53 PM UTC

Post by tonyedgecombe » Sat, Jul 19, 2025, 8:54 PM UTC

aapoalas wrote: post #55

School-Cotton wrote: post #45

Earlier quoted context omitted.

Yes you would need an escape hatch, but your example is wrong. Vec can't be Copy, because it has a destructor. This program fails to compile: #[derive(Clone, Copy)] struct S; impl Drop for S { fn drop(&mut self) {} } fn main() {}

Actually; I'm not sure I'm wrong. If Copy was automatically derived based on fields of a struct (without the user explicitly asking for it with `#[derive(Copy)]` that is, as the parent comment suggested the OP is asking for), then your example S and the std Vec would both automatically derive Copy. Then, implementing Drop on them would become a compile error that you would have to silence by using the escape hatch to…

Post by lblume » Sat, Jul 19, 2025, 8:58 PM UTC

al_fanta wrote: post #65

mikepurvis wrote: post #13

Earlier quoted context omitted.

There's the practical end goal benefit of safer and more robust programs, but I think there's also the piece that pg talks about in Beating The Averages which is that learning how to cooperate with these conventions and think like there's the borrow checker there makes you a better programmer even when you return to languages that don't have it .

> makes you a better programmer If a language is bad, but you must use it, then yes learn it. But, if the borrowchecker is a source of pain in Rust, why not andmit it needs work instead of saying that “it makes you better”? I’m not going to start writing brainfuck because it makes me a better programmer.

Post by nine_k » Sat, Jul 19, 2025, 9:01 PM UTC

eigenspace wrote: post #67

nine_k wrote: post #56

Earlier quoted context omitted.

One good RCE in production could alter this perception quite a bit. "The mosquito repellent is useless, I see too few mosquitos around me anyway."

The author is a bioinformatician writing scientific software, and often switching back and forth between Rust, Julia, and Python. His concerns and priorities are not the same as people doing systems-level programming.