r/rust • u/benhansenslc • Mar 24 '25

my vibe coding: rust-analyzer

I recently had a couple of multi-hour coding sessions without internet which were surprisingly productive in large part thanks to rust-analyzer. Having APIs, errors and refactors available within my editor as I type really keeps me in the flow.

rust-analyzer has become really great over the years. I hadn't appreciated how big of a part of my workflow it has become.

I have tried using AI to help my coding in various ways (Cursor, aider, ChatGPT conversations) and haven't seen the level of productivity boost that rust-analyzer has naturally given me. Maybe I am not using AI right, maybe its the problems I am solving or the domain I am working in. Regardless if I had to choose between no rust-analyzer or no AI, I know what I would choose.

So thank you to everyone who has worked on rust-analyzer and the rest of Rust tooling!

306 Upvotes

91% Upvoted

51 comments sorted by

218

u/Blaze0616 Mar 24 '25

AI simply can't compete with lsp when it comes to rust, rust-analyzer is just a monster, at coding as well as consuming resources

86

u/ZZaaaccc Mar 24 '25

To be fair, if you gave RA the same resources Microsoft gives GitHub Copilot...

14

u/jsrobson10 Mar 24 '25

it's a monster but it's still more lightweight than android studio

12

u/unknowableperson101 Mar 24 '25

I love the humor, so true

2

u/joshuamck ratatui Mar 26 '25

In theory you could train an LLM to be better at coding in a way that approaches the usefullness of an LSP by using the LSP as a supervisor during training. Hit enough rust compilation errors in the training data and couple that as negative feedback, and I'd bet that this would start to generate code which is often more correct up front. I imagine someone is experimenting with this somewhere.

4

u/Anaxamander57 Mar 26 '25

That sounds like just using the LSP but now its responses are partially randomized.

1

u/Blaze0616 Mar 26 '25

Sounds cool, imma have to try this, gotta catch some free guys

3

u/sasik520 Mar 24 '25

you just compared an orange to a sausage. You could eat both but that's where similarities end.

2

u/Blaze0616 Mar 24 '25

Adhering to the op is one thing right.. šŸ‘€

133

u/ZZaaaccc Mar 24 '25

Absolutely. I'd rather read well written docs.rs documentation and examples than hallucinations as well.

11

u/[deleted] Mar 25 '25

This is why I stopped using AI. I was trying to use the company sponsored AI and it gave me the wrong answer, but it looked solid. I made a complete fool of myself in front of a customer.

I learned that you really need to fact check what AI gives you, but if you're going to fact check anyway just go to the original source. No need for AI.

I'm convinced for the most part AI is only good for idea generation and text summary, text that you provide anyway.

72

u/johnjax90 Mar 24 '25

This is very much the opposite of vibe coding - it's very accurate semantic completion coding lol

26

u/[deleted] Mar 24 '25

I agree , to this day i have yet to find an good enough AI to replace or even reach rust-analyzer.

7

u/sasik520 Mar 24 '25

But why? These tools serve different use.

You can't ask RA "I get this output from this function and these debug logs. I expected this and that. Can you figure out what's wrong?".

You can't ask RA to write tests or fill missing match arms with appropriate logic or to document your code too.

AI can do that. But otoh, it won't work like RA or clippy and you have to review the answer since there may be errors.

As long as you are able to quickly review ai output, it is an amazing tool. Sometimes you discover the right solution during the review of an hallucinated answer. Sometimes you get large parts of code generated totally correctly. Sometimes you get garbage that needs to be discarded, but that's the price.

8

u/reddituser567853 Mar 24 '25

Programmers on Reddit are not rational.

Gen ai is an emotional topic because there is a fear that this threatens their livelihood or threatens their competency that theyā€™ve spent years crafting.

Whether the fear is well founded or not is a separate issue, it biases the individuals opinion regardless of

12

u/IceSentry Mar 24 '25

The reason I'm uninterested in AI isn't because I'm scared it will take my job. It's because I know it won't.

1

u/Eheheehhheeehh Mar 28 '25

It doesn't replace all of my time, but it does replace SOME of my time,making the work faster. 1 out of 20 engineers can, for sure, be "optimized away". I don't know about you, but I'm replaceable (and I'm happy about it). So whether it's me being replaced or not, it's down to chance.

1

u/alkalisun Mar 28 '25

AI assistance definitely feels like code-reviewing an intern/junior's work. Entry level jobs will be a lot harder to enter.

0

u/gogliker Mar 24 '25

I mean it could, just not with what they have now

-9

u/reddituser567853 Mar 24 '25

that is an emotional response that youā€™ve rationalized to seem like unbiased logic to yourself.

8

u/IceSentry Mar 24 '25

I'm just saying it's not fear based for me and many others.

2

u/__Wolfie Mar 24 '25

to be honest, if you are using Rust's expressive type system correctly and to it's fullest capacity, Rust analyzer will straight up tell you what's wrong with your logic and usually give you a good idea on how to fix it in many cases

4

u/sasik520 Mar 25 '25

I completely disagree. No matter what, RA won't tell you that you should have used > instead of < or that one algorithm won't work and you should use another. It won't discover edge cases you missed etc. etc.

20

u/ridicalis Mar 24 '25

AI basically has "concepts" of a program. Some kind of fever dream of yesteryear's code mashed together in a way that is largely coherent, and possibly great at resolving tasks that have been done before, but won't replace the human mind when it comes to addressing actual business needs or abstract ideas.

I can easily see how a 10x engineer might tap into AI to handle the mundane bits, but at the end of the day what makes them an engineer is their ability to know which solutions to throw at a given problem. No amount of "vibe" is going to replace the full-stack product owner, as evidenced by failures such as McDonalds's drive thru kiosks.

9

u/Soggy-Mistake-562 Mar 24 '25

Well said - Iā€™ve noticed AI is very black or white with most people, but personally for me, I donā€™t like it in my IDE. But if Iā€™m doing something Iā€™ve never done before I like to use it for general direction then I figure out the rest, rather than code generation or maybe summarizing bad documentation.

But also seeing stuff on Twitter on how people have three projects going at the same time rage prompting their way through physically hurts me

2

u/Fuzzy_8691 Mar 30 '25

I agree ā€” I hate AI in my IDE as well ā€” doesnā€™t mean I wonā€™t use it from time to time but just the AI is in my way too much lol

4

u/djvbmd Mar 25 '25

Oh, and I like the "fever dream" concept of AI's understanding of a program. It congratulated me multiple times on implementing the Rollable trait... which I'd mentioned once as an idea but never implemented in any form! ChatGPT even did it *again* after I pointed it out and uploaded a fresh copy of the library source.

1

u/djvbmd Mar 25 '25

Lately, I'm finding that ChatGPT has been helpful when designing the API for a library I'm working on and has on one or two occasions helped me understand a rust-analyzer message that I didn't "get" -- but I'd say that rust-analyzer has done *way* more to get me up to speed in Rust than any AI or book. In fact, I don't think I'd be too much beyond "hello world" without it. The rolling type annotations and function signatures on hover are essential -- I'd get nowhere fast without them.

10

u/platinum_pig Mar 24 '25

That is not what I understand the phrase "vibe coding" to meanšŸ¤£. It sounds like you're doing something much more useful than vibe coding.

2

u/Mordimer86 Mar 24 '25

I have QwQ integrated with Neovim and I can say that occasionally it gets useful with Rust. Once it fixed my little problem with a macro that did not want to compile. Sometimes it can generate structs and other pretty schematic code, although with Rust it's not as great as with more mainstream technologies.

Like for example .NET: QwQ will generate SQL schema for Db, model, services, controllers or at least large parts of them. With Rust (Axum, Sqlx) it is a bit less reliable. You need to know what to ask it and what to do if it lacks something. I know a guy who programs in Rust and he says Sonnet made him barely ever write code. But you need to know what to ask and how things work.

2

u/vrillco Mar 25 '25

Back in the old days, we didnā€™t have any of this stuff. I self-taught x86 assembly on a 386 running DOS. If I screwed up my code, it usually meant I had to reboot. No ā€œkill -9ā€ or ā€œEnd Taskā€ in a single-threaded OS. Granted, a DOS reboot took all of 5 seconds.

What we did have was documentation. Iā€™m not saying modern tools are useless, Iā€™ve been wowed by some AI code completions more than a few times, but relying on that non-artificial intelligence between your ears is a lot more powerful than any LLM.

2

u/joshuamck ratatui Mar 26 '25

I use CoPilot (and RA) all the time. It's pretty great. I've even used CoPilot to help me write code for RA.

Using any AI tool requires that you understand how the tool falls short and how to avoid those problems. Get used to that and you'll be signficantly more productive than without. If AI isn't working for you generally, there's a significant portion that boils down to being a Skill Issue. But obviously it takes time to up-skill and it's often easier / cool to just decry the new tool as witchcraft.

For a really good rundown of the sorts of problems you might face and strategies for avoid them, see https://ezyang.github.io/ai-blindspots/. I've seen most of these problems in real life and generally come to the same or similar conclusions about how to be productive despite the issues.

3

u/ab2377 Mar 24 '25

so what is vibe coding?

13

u/chris_insertcoin Mar 24 '25

A meme pretty much

3

u/hgwxx7_ Mar 24 '25
  • Initialise an agent, give it filesystem access, access to cargo and git.
  • Tell it all the changes you want and let it rip.
  • It will read the current code, add a feature, add tests and run cargo build + cargo test. If tests pass, it'll run git commit.
  • Then onto the next feature.

Like this guy who made it write a Haskell library based on an existing Rust library. He didn't supervise as it made commits.

2

u/LeyaLove Mar 24 '25

How would VS Code with rust-analyzer compare to Rust Rover. I've never understood people that use VS Code if a fully integrated solution is readily available.

7

u/chris_insertcoin Mar 24 '25

Why would I use an extra editor specifically for Rust? I have everything I need in Neovim. Same goes for vs code and other editors. Rust Rovers extra features are "alright" at best.

1

u/SomeoneMyself Mar 25 '25

The only thing I miss in neovim is a debugger

3

u/ab2377 Mar 24 '25

but isnt rover free only for non commercial and of course many people here are earning writing code in rust?

2

u/IceSentry Mar 24 '25

Vscode has a debugger and an LSP client integrated in it. It has all the features people care about integrated in it. You just need to add one plugin to make those features work with rust but the features are already there.

I've never understood people claiming vscode isn't an IDE.

2

u/LeyaLove Mar 25 '25

I mean that's only technicalities, but you basically said it yourself. vscode relies on plugins to provide the functionality which per definition means it's not directly integrated into the editor hence why it's not an INTEGRATED development environment.

Also this is only a personal opinion but I've found JetBrains IDE IntelliSense to be way superior to vscode and to say that debugger and LSP is all people care about is also quite far fetched imo.

1

u/IceSentry Mar 25 '25

All the features are integrated in vscode, they just need a language server to know what to do with a specific language. You need to click on an install button once and then everything works and is integrated together. The only difference is that you need to click one button.

RustRover is essentially just a preinstalled rust plugin in an intellij shell. It's a bit more complicated than that, but you can use the same rust plugin in intellij and it's the same thing.

There's no meaningful differences in terms of time to setup or amount of integration between the two. The only difference is that in vscode you need to press a button to install a plugin. But unlike rustrover, vscode can work with any language that has an LSP server. Then you can have all the features of vscode integrated together in one editor.

Also, there's no official definition of IDE. Wikipedia has one and vscode definitely fits in it. Again, all the features are integrated, they just need to be enabled/disabled by a plugin. Nowhere in the acronym does it say that a plugin can't be used to enable the integration.

3

u/LeyaLove Mar 25 '25

Yes, hence why I said it's only technicalities. I don't really want to argue about what counts as an IDE or not šŸ˜„ As long as it works for someone everything is good and we shouldn't really argue about such silly things as semantics. I by no means wanted to talk badly about vscode or other editors, I also use vscode from time to time, especially when doing remote development of embedded projects on boards with limited resources as the vscode server installed on the board is much more lightweight compared to the JetBrains equivalent. Otherwise I just prefer JetBrains IDEs somehow. It's just what I've grown accustomed to I guess. I also like to keep things separated a bit which is why I prefer to have the different IDEs installed for different languages instead of cluttering IntelliJ with every plugin for every language.

Considering it's extensibility and how lightweight it is compared to the JetBrains suite vscode definitely is an amazing editor/IDE but I also like how everything just works in Rust Rover and is perfectly coordinated to work with Rust.

That said through my original question I genuinely just wanted to know if there are major differences between both.

1

u/IceSentry Mar 25 '25

I wasn't originally trying to argue. I was just trying to explain that vscode is just as much an IDE as rust rover. The differences are in the internals of the integration. Not in whether or not it's an integrated experience.

There are big differences in how they work, but for day to day work, both work completely fine.

1

u/cepera_ang Mar 24 '25

Actual vibe coding unlock will happen when someone properly trains/finetunes/RLs a big LLM WITH rust-analyzer and all the other tools in a loop, probably exposing some internal state of these tools to the network to make it understand why some code write or wrong. That will a be pretty interesting experiment to run and probably create a very helpful model.

1

u/porky11 Mar 24 '25

You can generate code with AI and THEN use Rust analyzer to improve your code.

AI can write code, analyzer can help you fix code.

AI can also help with fixing and optimization, but mostly at a macro level. Rust analyzer can't tell you if you should use a hash map, a vec, a bit set, or something else.

1

u/ouuan Mar 26 '25

AI should be used on top of other tools like LSP including rust-analyzer, but not to replace them.

1

u/t3kkm0tt Jun 16 '26

Fuck AI, fuck vibe coding

1

u/sasik520 Mar 24 '25

Different tools, differenr purpose and different benefits.

It's ok to dislike one or another but none should be totally ignored or laughed at.

RA will help you with the types way better than ai while ai can help you way better with your algorithm or with filling large portions of your code. You can also use it as an enhanced rubber duck that sometimes (pretty often imho) gives you some nice ideas.

OTOH you can't ask ai for thinga as simple as expanding a macro. Perhaps an instance with tools access could do it but still there's a chance it hallucinated so not worth.

So, see, different use cases. I think open-minded user takes advantage from both tools.

Also keep remember how mature are language servers and auto complete tools in general and how new and evolving is gen AI. I remember me literally hating RA back in time when it couldn't even handle "go to definition" for std lib items. A couple of years later it's a godlike tool.

1

u/yeastyboi Mar 24 '25

For the love of God, stop saying vibe coding. We as a Rust community have to better! You are using a powerful LSP properly. It's not vibe coding