Is it guaranteed that 0i32 / 0 panics? It seems so ( Playground ). But where is this documented? I searched here, and didn't find anything yet (but maybe I missed it?). Oh, now I found something here: impl Div<i32> for i32 But that's pretty hidden, and when I look at the implementations for &i32 (…

[image] steffahn: I don't think anyone would ever actually question the fact that /= gives the same results as / for primitive types or that the &-versions of the trait implementations don't do anything different. So I understand that as I can assume that integer division by zero in Rust alwa…

[image] H2CO3: I don't think DivAssign needs that extra documentation, because it is generally understood as being a shorthand for lhs = lhs / rhs. I always thought like that too, but note that implementation may differ and there are types which don't implement it, for example. I stumbled up…

[image] jbe: but note that implementation may differ They generally shouldn't differ. That's bad enough even without any regards to documentation or formal guarantees. In general, DivAssign should be implemented in terms of Div, or vice versa (sometimes the former option can avoid allocations…

[image] jbe: And I think in either case it's not a real problem, but I was on guard due to previous surprises with Rust. I guess, if you love surprises with Rust, look no further than the order of evaluation for the arguments of +=, right? fn main() { let mut x = 1; println!("\ni32 +…

:astonished: Playground or it didn't happen!!1! :laughing:

I guess that also explains the weird evaluation order shown by @steffahn ?

[image] jbe: Playground or it didn't happen!!1! :laughing: Here it is , for your convenience (that's just the copy-paste from the post though, no adjustments).

Thanks, it was mostly a humorous comment from my side, making fun of the "link or it didn't happen" meme.

Given you said you read the reference about /=, you sure didn’t pay enough attention (okay… maybe you didn’t say that? :thinking: but you sure should have read that part of the reference for this topic :stuck_out_tongue_winking_eye:). It’s right there … Evaluation of compound assignment expressions…

Guarantee that 0i32 / 0 panics?

tczajka June 29, 2023, 9:09am 19

Technically Div only describes the behavior of 0.div(0), not of 0 / 0. The latter expression does not call Div::div for i32.

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Guarantee that 0i32 / 0 panics?

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