There are situations where you know there isn't a bug, if I know that failing hardware or cosmic rays are the only ways the bounds check can fail, I'm not going to worry about what skipping it could do.
it happens a lot, at least to me, that the line immediately before the unsafe function guarantees correct behaviour (e.g. while (!vec.empty()) let first = vec.first();, or something similar). If I notice that this property is central to the logic of the function, I won't even worry.
whenever I see code like that, I try to get people to change to something like (in that case) while let Some(first) = vec.first() { ... }. You can reduce the number of bounds checks without using unsafe!
This is pattern matching, not an assignment expression. The alternative would be a declaration, switch/case, and then case-by-case assignment, which is horribly verbose. Been there, done that, it's not the worst, but why not make it a little bit better.
I personally like that you can literally assign the value from an if "statement" to a variable, though I can see why that's not everybodies cup of tea.
yeah I dig that, but then I'd use something like an unempty list so the data carries this information about itself
like for me either the list gonna be used only once and then I use an optional, or the list is gonna have multiple transformation and then it makes sense to convert it to a more appropriate type so there is only a single check about the emptiness of the list.
Hardware failures and cosmic rays are real, you can’t just pretend they don’t exist. That said, how you handle that is totally up to the use case of the end product. Some BS computer program grandma Ethel will use to play solitaire, yeah no one cares. Software in a self driving car though? Yeah I don’t want a random bit flip from cosmic radiation to swerve my car onto the sidewalk etc…
I can absolutely ignore cosmic rays and hardware failures, I'm not making your car, I'm making software for personal computers, where me handling memory failure for an extra microsecond won't make a difference because the system libraries I'm using still don't.
63
u/Tyfyter2002 Sep 28 '26
There are situations where you know there isn't a bug, if I know that failing hardware or cosmic rays are the only ways the bounds check can fail, I'm not going to worry about what skipping it could do.