[pron]

That's a very narrow way of looking at things. ATS has a much stronger "deterministic safety net" than Rust, yet the reason to use Rust over ATS is that "fighting the compiler" is easier in Rust than in ATS. On the other hand, if any cost is worth whatever level of safety Rust offers for any project, than Rust wouldn't exist because there are far more popular languages with equal (or better) safety. So Rust's design itself is an admission that 1. more compile-time safety is always better, even if it complicates the language (or everyone who uses Rust should use ATS), and 2. any cost is worth paying for safety (or Rust wouldn't exist in the first place).

Safety has some value that isn't infinite, and a cost that isn't zero. There are also different kinds of safety with different value and different costs. For example, spatial memory safety appears to have more value than temporal safety (https://cwe.mitre.org/top25/archive/2025/2025_cwe_top25.html) and Zig offers spatial safety. The question is always what you're paying and what you're getting in return. There doesn't appear to be a universal right answer. For some projects it may be worth it to pay for more safety, and for other it may be better to pay for something else.

[7bit]

You’re changing the argument. The point wasn’t whether more safety is “worth it”, but that comparing ease while ignoring which invariants are enforced is misleading. Zig can feel simpler because it encodes fewer guarantees. I’m not saying one approach is better, only that this comparison shifts the goalposts.

[pron]

Then we're in agreement. Both languages give you something that may be important, but it has a price.

[7bit]

You're changing the argument again. I'm not in agreement with your statement.

[tcfhgj]

Imo "safety" in safe Rust is higher than it is in more popular languages.

Data races, type state pattern, lack of nulls, ...

[pron]

This is comparing what Rust has and other languages don't without also doing the opposite. For example, Java doesn't enforce data-race freedom, but its data races are safe, which means you can write algorithms with benign races safely (which are very useful in concurrent programming [1]), while in Rust that requires unsafe. Rust's protection against memory leaks that can cause a panic is also weaker, as is Rust's ability to recover from panics in general. Java is now in the process of eliminating the unsafe escape hatch altogether except for FFI. Rust is nowhere near that. I.e. sometimes safe Rust has guarantees that mean that programs need to rely on unsafe code more so than in other languages, which allows saying that safe Rust is "safer" while it also means that fewer programs are actually written purely in safe Rust. The real challenge is increasing safety without also increasing the number of programs that need to circumvent it or increasing the complexity of the language further.

[1]: A benging race is when multiple tasks/threads can concurrently write to the same address, but you know they will all write the same value.

[Ygg2]

> 1. more compile-time safety is always better, even if it complicates the language (or everyone who uses Rust should use ATS), and 2. any cost is worth paying for safety (or Rust wouldn't exist in the first place).

You keep repeating this. It's not true. If what you said was true, Rust would have adopted HKT, and God knows whatever type astronomy Haskell & Scala cooked up.

There is a balancing act, and Rust decided to plant a flag in memory safety without GC. The fact that Zig, didn't expand on this, but went backwards is more of an indictment of programmers unwilling to adapt and perfect what came before, but to reinvent it in their own worse way.

> There are also different kinds of safety with different value and different costs. For example, spatial memory safety appears to have more value than temporal safety (https://cwe.mitre.org/top25/archive/2025/2025_cwe_top25.html)

How did you derive this from the top 25 of CWEs? Let's say you completely remove the spatial memory issues. You still get temporal memory issues at #6.

[pron]

Rust does have a GC, but I agree it planted its flag at some intermediate point on the spectrum. Zig didn't "go backwards" but planted its own flag ever so slightly closer to C than to ATS (although both Rust and Zig are almost indistinguishable from C when compare to ATS). I don't know if where Rust planted its flag is universally better than where Zig planted its flag, but 1. no one else does either, 2. both are compromises, and 3. it's uncertain whether a universal sweet spot exists in the first place.

> How did you derive this from the top 25 of CWEs? Let's say you completely remove the spatial memory issues. You still get temporal memory issues at #6.

Sure, but spatial safety is higher. So if Rust's compromise, we'll exact a price on temporal safety and have both temporal and spatial safety, is reasonable, then so is Zig's that says, the price on temporal safety is too high for what you get in return, but spatial safety only is a better deal. Neither go as far as ATS in offering, in principle, the ability to avoid all bugs. Nobody knows whether Rust's compormise is universally better than Zig's or vice versa (or perhaps neither is universally better), but I find it really strange to arbitrarily claim that one compromise is reasonable and the other isn't, where both are obviously compromises that recognise there are different benefits and different costs, and that not every benefit is worth any cost.

[Ygg2]

> Rust does have a GC

It doesn't. Not by any reasonable definition of having a GC.

And "opt-in non-tracing GC that isn't used largely throughout the standard library" is not a reasonable definition.

> Nobody knows whether Rust's compormise is universally better than Zig's

When it comes to having more segfaults, we know. Zig "wins" most segfaults per issue Razzie Award.

This is what happens when you ignore one type of memory safety. You have to have both. Just ask Go.

[pron]

> And "opt-in non-tracing GC that isn't used largely throughout the standard library" is not a reasonable definition.

Given that refcounting and tracing are the two classic GC algorithms, I don't see what specifying "non tracing" here does, and reference-counting with special-casing of the one reference case is still reference counting. I don't know if the "reasonable definition" of GC matters at all, but if it does, this does count as one.

I agree that the one-reference case is handled in the language and the shared reference case is handled in the standard library, and I think it can be reasonable to call using just the one-reference case "not a GC", but most Rust programs do use the GC for shared references. It is also true that Rust depends less on GC than Java or Go, but that's not the same as not having one.

> When it comes to having more segfaults, we know. Zig "wins" most segfaults per issue Razzie Award.

And Rust wins the Razzie Award for most painful development and lack of similarly powerful arenas. It's like declaring that you win by paying $100 for something while I paid $50 for something else without comparing what we got for the money, or declaring that you win by getting a faster car without looking at how much I paid for mine.

> This is what happens when you ignore one type of memory safety.

When you have less safety for any property, you're guarnateed to have more violations. This is what you buy. Obviously, this doesn't mean that avoiding those extra violations is necessarily worth the cost you pay for that extra safety. When you buy something, looking just at what you pay or just at what you get doesn't make any sense. The question is whether this is the best deal for your case.

Nobody knows if there is a universal best deal here let alone what it is. What is clear is that nothing here is free, and that nothing here has infinite value.

[Ygg2]

> I don't know if the "reasonable definition" of GC matters at all

If you define all non-red colors to be green, it is impossible to talk about color theory.

> And Rust wins the Razzie Award for most painful development and lack of similarly powerful arenas.

That's a non-quantifiable skill issue. Segfaults per issue is a quantifiable thing.

> When you have less safety for any property, you're guarnateed to have more violations.

If that's what you truly believed outside some debate point. Then you'd be advocating for ATS or Ada.SPARK, not Zig.

[pron]

> If you define all non-red colors to be green, it is impossible to talk about color theory.

Except reference counting is one of the two classical GC algorithms (alongside tracing), so I think it's strange to treat it as "not a GC". But it is true that GC/no-GC distinction is not very meaningful given how different the tradeoffs that different GC algorithms make are. Even within these basic algorithms there are combinations. For example a mark-and-sweep collector is quite different from a moving collector, or CPython uses refcouting for some things and tracing for others.

> That's a non-quantifiable skill issue. Segfaults per issue is a quantifiable thing.

That it's not as easily quantifiable doesn't make it any less real. If we compare languages only by easily quantifiable measures, there would be few differences between them (and many if not most would argue that we're missing the differences that matter to them most). For example, it would be hard to distinguish between Java and Haskell. It's also not necessarily a "skill issue". I think that even skilled Rust users would admit that writing and maintaining a large program in TypeScript or Java takes less effort than doing the same in Rust.

Also, ATS has many more compile-time safety capabilities than either Rust or Zig (in fact, compared to ATS, Rust and Zig are barely distinguishable in what they can guarantee at runtime), so according to your measure, both Rust and Zig lose when we consider other alternatives.

> Then you'd be advocating for ATS or Ada.SPARK, not Zig.

Quite the opposite. I'm pointing out that, at least as far as this discussion goes, every added value comes with added cost that needs to be considered. If what you truly believed is that more compile-time safety always wins, then it is you who should be advocating for ATS over Rust. I'm saying that we don't know where the cost-benfit sweet point is or, indeed, even if there's only one such sweey point or multiple. I'm certainly not advocating for Zig as a universal choice. I'm advocating for selecting the right tradeoffs for every project, and I'm rejecting the claim that whatever benefits Rust or Zig have compared to the other are free. Both (indeed, all languages) require you to pay in some way to get what they're offering. In other words, I'm advocating can both be more or less appropriate than the other, depending on the situation and against the position that Rust is always superior, which is based on only looking at its advantages and ignoring its disadvantages (which, I think, are quite significant).