Comment by mountainriver
13 hours ago
I love Go and used to write it heavily for anything non LLM based.
Now that we have agentic coding I just write everything in Rust and couldn’t be happier. The struggle with rust was writing it, go was made so it was easy to write for mid level engineers. Now that we have agentic coding I’m not sure Go’s value prop holds up anymore
My rust services have been nothing short of amazing from a performance and reliability perspective
In my experience LLMs (I speak mainly of Claude Code & Cursor) write very poor quality Rust.
They treat it like it's JavaScript, falling back to using String/&str needlessly instead of making new types. They do ugly `static Mutex<Refcell<` a-la global JS variables for info sharing instead of working out the lifetimes to do it properly. It loves making functions infallible and then panic-ing within them and certainly I wouldn't use them for unsafe at all - they hallucinate safety comments which are in fact, totally unsound.
Of course these are all surmountable with an experienced developer to regularly step in and unfuck the code, but forcing them into 'harder' territory where every problem is not solved by a .clone() and an Arc<Mutex<>> means they will spend minutes 'thinking' about basic lifetime issues until I step in and add the missing `move` in a closure.
That is interesting. I make LLMs write C with the general hope that a simpler language they can manage well. That is not entirely true, though. They reason about C fluently indeed. The problem is, Claude pumps lots of bad C into the codebase if left unattended for 5 min. So, I need some clean-up passes afterwards to get to some acceptable quality level (both by LLMs and my own eyes). At which point, Claude sees the problem clearly, for some mysterious reason. Also, I use a C dialect heavly influenced by Go (slices, generics, no smart tricks, virtually no malloc).
LLMs generally write poor quality anything. It'll [usually] work, but it'll need massive refactoring to get in a maintainable and efficient state.
You gotta know how to write Rust (and general software arch) first. LLMs + Rust have been great for me.
"Write an SQL Repository with this interface"
Sweet - no need for SQLc or an ORM
same experience. any good claude skills to ease the pain?
Maybe true 6 months ago, but now it's better than any Rust Dev, as long as you guide it and not just let it rip on a full service/app unsupervised.
It's better than any Rust dev... as long as you guide it
What?
For me the bottleneck now is reading/reviewing code, not writing code. As you said, AI makes it way easier to write, but do you not review the code? And isn't a verbose, cryptic language with lots of nitty gritty memory management not harder to read/review?
I'm not sold on Rust being a great language to use with AI unless the reason to use it is a lot more than just Rust being fashionable.
I find Go harder to review than Rust.
The verbose error handling diluting the interesting parts is one thing, but the main issue is the weak type system. Having to read the callee's code to check if it deviates from `res xor err`, or if it mutates its arguments. Figuring out which interface that `func (o *Obj) ()` is implementing, if any. Dealing with documentation that is a wall of 100 disappointing oneliners all repeating the function name.
Rust is information-dense and takes longer to master, but it's not inherently cryptic, there's a finite amount of things to know. Memory management sometimes take a bit of thought to write, but it's straightforward to review, you can trust it's correct if it compiles, you just keep an eye out for optimizations.
I don't see the difference in exploring an dense custom type system versus a flatter one. Both force you to look things up when you don't know about them.
In my opinion these problems originate in architectural style. Much of the open source written today is designed to impress the audience instead of focusing on the problem.
In my experience, Rust is only mildly unpleasant to review, if only because the GitHub PR review interface is not an IDE. It can be hard to tell why .as_ref()s and whatnot had to be used without being able to hover over a variable to see its type. This is probably because of the language's preference for type inference, though personally I would rather that than having to skim over explicit types.
Compared to Rust, Go as a language requires a lot more effort to review. You have to be on the lookout for basic gotchas like not checking if a pointer is nil, placing `defer` in the wrong place, using a result when err isn't nil, and so on. Plus, diffs are messier because unused variables are a compilation error, and _, err := can change into _, err = solely due to new lines above.
And := not being = can really matter for variable shadowing.
Absolutely insane syntax choice in a language where everything returns 2 values. At least do var:, err: =
It's the same logic for human and for AI code: In Rust the compiler catches many bugs so you don't have to.
If the LLM gives you safe code you know there are entire classes of things you don't have to review for.
That said, I agree with you. My experience is that LLMs are great if you are highly competent in the domain in which you let them work. And it's probably easier to be competent in Go than in Rust.
Safe? No compiler is going to catch badly designed code, or intentionally backdoored code. Memory leaks as well. Compilers are the ground floor of validation and the least of your problems with AI generated code.
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I found it's the opposite. Thanks to LLM's whole classes of problems otherwise solved by using Rust are gone. It's now more important that the generated code is easy to read.
The build time and space for rust is awful for fast iteration e.g change a thing, verify.
Reading the code? Who has the time.
Aah, I am sure the chickens of vibe coded origin, will never come to roost.
Time isn't the constraint here, but ability. Someone complaining about how hard Rust is to write is probably not capable of reviewing Rust code very well.
The usual reaction or opinion from e.g. good C++ programmers switching to Rust is that the added guardrails and expressivity are great and make things easier.
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IMO neither Go nor Rust are great for reading/reviewing code.
Go is too verbose and the type system isn't expressive enough. Rust code is littered with little memory management details and it requires tons of third party libraries.
I think coding agents will eventually be able to get the low level details right on their own. Reviewers should be able to focus on architecture, design and logic mistakes.
I also think we need a high level formal specification language to tell agents what we expect them to do.
> I also think we need a high level formal specification language to tell agents what we expect them to do.
Let’s make that specification Turing complete while at it.
Jokes aside, IMO it will be a good natural progression. Specify the problem statement in LLM specification, generate the code in Go/Rust whatever is the language of your choice and review the generated code to make sure it adheres to the architecture/design principles that you have set.
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The benefit is if you lean heavily on types then successful compilation is a massive indicator in the feedback loop. Using stop hooks to ensure successful compilation after every iteration is a game changer. Go also has compilation of course but because the type system is so much more robust in Rust the compilation guarantees so much more about the behaviour of your program. You end up just code reviewing the shape and flow of data.
Code compiling is really the lowest bar of code validation, and doesn't say much of anything of the code running correctly. AI will pump out the most convoluted, over engineered, and at the same time sloppy code if you let it - and it will all compile fine.
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Go was never about being easy to write (thought it is), but it was always about being easy to read and it is, by far, the easiest language to read that I've ever used (and throughout the decades, I went through Basic, Pascal, C, Java, JavaScript, C#, TypeScript, Ruby and Python). That becomes even more important if you are not writing the code yourself...
it's too verbose, yet not explicit.
you need to know the conventions to spot what's not there (did you miss the error handling? or the magic comment for the whatever codegen serializer? c'est la vie!)
edit: just a few comments below an even better description of what I'm trying to convey: https://news.ycombinator.com/item?id=48264853
Disagree, if you miss the error handling the code won’t compile (unless you return _, which should be easy to spot)
The magic comment stuff is very much “do it once” and it’s done (for example if using go generate).
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> The struggle with rust was writing it, go was made so it was easy to write for mid level engineers.
In practice, anything that makes it easier for humans to program also makes it easier for LLMs to program.
You also wont typically learn that the LLM is close to the limits of understanding your code base until after it has blown past it's own capabilities, leaving you with a mountain of code that you are not skilled enough to fix.
Java, C# are good choices as they tend to enforce a certain structure. Go, good because it's very readable even if you dont know the language.
C++, Rust are poor choices unless you are already a senior in that language.
Go is really easy to read and write, even if Go's philosophy means that some of that feels clunky because it's less featureful than other languages. It makes up for it with a comprehensive stlib that makes it trivial to build services with few to no third party dependencies.
I don't think the value prop has changed at all there. One day the AI gravy train will stop and people who used AI to punch above their weight will no longer be able to debug the stuff they built unless they put in the hard work of learning the language.
Nothing to worry about with Go in that respect because of how much it's been designed to be simple. Even the annoying err/nil checks you need to do all the time are in service of that simplicity. It gets old fast but it leaves nothing to the imagination.
The value prop of Go in not on writing, but in reading and comprehension by people different from the autor(s). For systems expected to last some years, this translates in reduced total cost of maintenance over the life of the system (in my experience typically 80% or more of the total cost) and facilitating traspassing maintenance to diferent people than the authors. In use cases where Go has "good enough" performance, for backend systems with business logic and small amount of "bare metal" programming, I recommend Go to teams instead of Rust. When extreme performance and reduced memory footprint is more important than the other properties, Rust is better than Go.
>Now that we have agentic coding I just write everything in Rust and couldn’t be happier. The struggle with rust was writing it, go was made so it was easy to write for mid level engineers. Now that we have agentic coding I’m not sure Go’s value prop holds up anymore
Agents seem to have a better time with Go. Humans need to review the agents outputs and in general they have an easier time to do it with Go.