> Most of us are writing web apps

Indeed. I'm a Rust dev somewhere it actually matters (video dev - we have to process 60 frames a second, for hours/days on end, with completely predictable performance, without crashing once) and I'd never pick it if I just wanted to build a webapp where nothing really matters and if the whole thing falls over we can just put it in a retry loop.

There's plenty of code out there that /cannot/ be written in Ruby/Python/Go/C#. Rust solves some really hard problems for people working on that type of code. But it's not what most people on HN are working on.

I think the problem is that a lot of web developers do not really understand that this type of code exists, and that languages which do not target web development can be exciting.

Your video app is a perfect example of where Rust shines. I'd add embedded development, data-intensive, fault-intolerant systems and game engines are perfect for this language.

But without even going as far as frontend web applications, stuff like backend services, system services, GUI applications, CLI applications, etc., don't actually need all that much memory safety and control over allocations.

Completely agree! When you need to compute numbers or deal with raw bytes, you have C. When you need to be high-level, you have Python, Java, C#, etc. Rust is applicable only in areas where you need both a high-level and systems language. Examples include interpreters, operating systems, browsers, game engines, etc. The hype of Rust just exceeds its problem domain.

This feels a bit like complaining that a tank is badly designed because nobody drives them on the highway...

My understanding is that Rust was designed to be a safe(er) language to write low-level system code than C/C++, not to compete with Python/Ruby/Java for web development applications.

I'm not complaining about Rust. It's a very good language.

I'm complaining about everybody on programming forums, including HN, seeing Rust as the replacement for most, if not all languages. My opinion is that Rust's ideal problem space is much narrower than people think.

Bingo, it's a true systems language. That said, the fact that people can and do write web applications(for practical reasons) with it kind of says something about it's breadth.

The whole point of system languages is that they reach the whole stack.

True, yet what you see around HN and other places are people trying to use it for web development.

Front end or back end? I see nothing wrong with rust on the back end, not sure how it would even work on the front

WebAssembly.

There seems to be a myth that Rust is unusual in being memory safe. All modern GCed languages are memory safe (assuming you don't do anything obviously unsafe like manipulate raw pointers, which some languages might let you do if you really want to).

>It is ironic to build super safe software, then deploying them on kubernetes, written in a GC'd language prone to nil dereference errors.

Nil dereference errors don't demonstrate an absence of memory safety. If the runtime checks for a nil reference before dereferencing and then raises an exception, that's perfectly safe.

I'm not sure if you understand what safe means in this context. One common example is modifying a vector element by reference. If you grab a reference to an item, push something else to the vector, then try to access through that reference, the vector may have re allocated during the push and you're either no longer looking at valid memory because it's been freed, or you're looking at a stale copy of the element.

I don't think the null handling in rust is about memory safety so much as it is their choice in error handling. If you come across a null pointer dereference and your code doesn't handle it, that's a hidden bug. Triggering an exception and handling it is a valid approach, but there are trade-offs. If no code handles the nil exception for example then it's no better than crashing as you would in C. Wrapping things up in try catch can lead to missing recoverable errors or unexpected states. The choice to disallow null is one to avoid common bugs, not one for memory safety, as far as I understand it.

I'm 100% sure that I understand what safe means in this context. All modern GCed languages are memory safe and will not access invalid memory regions unless you use specifically unsafe features.

> One common example is modifying a vector element by reference. If you grab a reference to an item, push something else to the vector, then try to access through that reference, the vector may have re allocated during the push and you're either no longer looking at valid memory because it's been freed, or you're looking at a stale copy of the element.

There aren't that many languages which both use GC and allow you to take references to elements of a vector. Go would be one example. I can assure you that you cannot access undefined memory regions by doing this in Go. (What would happen is that the original allocation backing the vector would be retained in addition to the new allocation.)

>If no code handles the nil exception for example then it's no better than crashing as you would in C

C programs are not guaranteed to crash when a pointer has an invalid value. Dereferencing a NULL pointer will reliably cause a crash if you're running the code on top of a modern general purpose operating system with memory protection, but invalid pointers (which don't necessarily have to be NULL) have the potential to access arbitrary memory regions without raising any kind of error.

> I can assure you that you cannot access undefined memory regions by doing this in Go.

Current implementation of slices and interfaces in Go is not memory safe in presence of data races:

https://blog.stalkr.net/2022/01/universal-go-exploit-using-d...

This is the kind of edge case you can find in lots of languages, including Rust (which has plenty of past and present soundness bugs).

Data races are violations of the memory model; of course any code which produces data races cannot be understood as memory safe?

As far as I remember, some languages like Java are memory safe even if the code produces data races. That means you can't have a reference to a value supposed to be of type A being actually of type B.

That's part of what the Rust borrow checker does for you: tracking who owns what and enforcing single ownership makes data races that much harder to cause.

Turns out I'm the one who forgot what memory safety is o.o I think the part that makes rust's memory safety special is that it also lacks garbage collection

Some people misunderstand unsafe for being anything more than plain memory corruption.

Nope, unsafe isn't a way to do dependent typing in Rust.

The reference to the slot in a vector has to be a kind of object which tracks the vector itself, and an offset into the vector. It can't just be a wrapper for a naked address.

You might be right for the majority, but there are many other large groups who don't have computers that are more than fast enough. There are a lot of interesting and complex problems that can be solved in something like rust that the languages you name cannot be used for. Right now I'm using C++, but rust is of real interest to me (as is ADA, which in some variants lets me prove my code correct)

"It is ironic to build super safe software, then deploying them on kubernetes, written in a GC'd language prone to nil dereference errors."

This is something that escapes a lot of people nowadays.

Everyone uses a browser and they are inherently unsafe.

I feel it is a bit ironic that Apple and Google rather introduce mitigations for C++ in their browser engines than introduce Rust into the codebase.

Meaning that Firefox's gains with Rust will eventually be lost given its market adoption is slowing reaching zero.

Google is investigating Rust as part of a multi-pronged strategy and, while it has the "this is not an official Google project" boilerplate, the `autocxx` crate (a header-parser/code-generator addon for the `cxx` interop crate) is by Google employees.

https://docs.google.com/document/d/e/2PACX-1vRZr-HJcYmf2Y76D...

https://www.chromium.org/Home/chromium-security/memory-safet...

https://github.com/google/autocxx