alt Hacker NewsI've had that moment in Rust too, where there was no composition that effected what I wanted, because supporting that model would have meant a very different backing data structure. However in that case I actually didn't care about the kind of correctness problem it was saving me from.
I've also had the converse experience, where I know full well that the structure I'm trying to impose is correct and quite efficient, but its part of the space that rust doesn't cover.
Rust is great. It's a noble attempt to bring a degree of correctness to a problem space that suffers from a great deal of slop. But to pretend that the model is complete, or that the design decisions that were made are perfect in every way, is just wrong. That the rust compiler and runtime can't support my construct isn't really an absolute value judgement on that idea in the first place. The rust compiler isn't really an oracle that tells you whether something is right or not in an arbitrary value system.
Right. The borrow checker is not always right. Just almost always right. It's not perfect (because halting problem), but… well I already said the rest in https://news.ycombinator.com/item?id=49287460
Still, I don't write Rust code the way I do "to make the compiler happy", but to make it correct. And sometimes it's correct to drop some "unsafe" because gosh darn it, you know it's fine this time.
And you're probably right for the cases you're thinking of, where Rust wouldn't let you (at least without unsafe). And maybe you're 99% sure about that.
But for every 100 changes we’re 99% sure won’t cause an outage, one will…
(also future changes may invalidate assumptions you relied on, of course, making it no longer true)
Do you have some examples you can share where you think Rust prevents you doing the right thing? The ones I run into tend to force me to think of the edge cases, and usually those edge cases don't even have a right answer.