Issues with rust-analyzer when using clippy as check command.

[unborn blaze]

Greetings.

I'm am using the rust-analyzer VSCode extension, and I'm trying to set it up to lint my code with clippy. I have the following configuration currently:

{
    "rust-analyzer.checkOnSave": true,
    "rust-analyzer.check.command": "clippy",
    "rust-analyzer.check.extraArgs": [
        "--",
        "-W",
        "clippy::all",
        "-W",
        "clippy::pedantic"
    ],
    "rust-analyzer.diagnostics.enable": true,
    "rust-analyzer.diagnostics.experimental.enable": false,
    "rust-analyzer.cargo.buildScripts.enable": true,
    "[rust]": {
        "editor.defaultFormatter": "rust-lang.rust-analyzer",
    }
}

I want to have the clippy::all and clippy::pedantic groups enabled, because I'm in the process of learning Rust and I think it might be helpful. The problem is that I'm having some weird issues with the extension.

Suppose we have the following code:

fn main() {
    let test = String::from("");
}

It will give me a warning:

warning: empty String is being created manually
  --> src/main.rs:13:16
   |
13 |     let test = String::from("");
   |                ^^^^^^^^^^^^^^^^ help: consider using: `String::new()`
   |
   = help: for further information visit https://rust-lang.github.io/rust-clippy/rust-1.93.0/index.html#manual_string_new
   = note: `-W clippy::manual-string-new` implied by `-W clippy::pedantic`
   = help: to override `-W clippy::pedantic` add `#[allow(clippy::manual_string_new)]`

So far so good. The problem is the following - after I go and refactor the code as suggested to use String::new() and then I save the file, the warning remains.

I don't understand why. I can open the command palette and run

rust-anaylzer: Restart server

Then the code gets analyzed again and the warning goes away as expected. But obviously that's not a solution.

Anyone have an idea how to fix this?

[little prism]

please dont do -W clippy::pedantic

you can remove all the flags

extra.Args

clippy::pedantic is sometimes really just annoying

[unborn blaze]

why not? I want it to be annyoing because I'm in the process of learning Rust

[little prism]

well

its not just annoying for you

its annoying for everyone

and half the lints in there are useless

[unborn blaze]

but is that the core of the issue I'm having?

where it's like the lint results get cached and stuck

unless i restart the language/extension server

I am trying to understand what is going on

[little prism]

i feel like this is a check on save issue

[unborn blaze]

indeed, it seems to be that way

it's like it's analyzing an old version of the file after i save it

i've search about this issue online for probably an hour, couldn't find any useful info

[little prism]

do you even see a spinning loader next to rust-analyzer?

when you save

[unborn blaze]

let me check

[unborn blaze]

do you mean in the bottom left corner?

[little prism]

on the left of rust-analyzer there should be a spinning loading wheel when you save

[unborn blaze]

I don't think so, but I think it's because my device is fast

[little prism]

have you restarted vscode at all?

[unborn blaze]

plently of times

i even created a brand new profile with no extensions or themes or anything

just for testing purposes

[unborn blaze]

other than rust-analyzer of course

so yeah, im completely lost right now

[slim frost]

i believe it may be rust-analyzer bug, it does exactly the same for me since like yesterday

[unborn blaze]

do you happen to know if there is an open issue about it?

[slim frost]

haven't checked i assumed it's just zed that broke

[unborn blaze]

i'm using vscode, but i assume zed is just a fork and they use the same extension?

or was it a different editor

[slim frost]

it's a totally different editor

but they do have rust analyzer extension

[unborn blaze]

let me see if i can downgrade

if that's even possible

so im using
0.3.2786

[slim frost]

zed has an open issue about that

apparently rustup component add rust-analyzer fixed it for somebody

[unborn blaze]

can you link the issue please?

[slim frost]

https://github.com/zed-industries/zed/issues/48811

[unborn blaze]

thank you

i think i might open an issue on the rust-analyzer repo, but let me see

still trying to install an older version

ok done, now im on 0.3.2777, gotta test

[slim frost]

i'm going to sleep now good luck

[unborn blaze]

good night, and thanks for the help

(i think it fixes the issue btw)

[little prism]

r-a works on neovim btw

[unborn blaze]

well, i am not sure what to say

which version are you using there?

0.3.2786?

[little prism]

idk

but some version from rustup

all of my ones work

[unborn blaze]

well the issue seems to be with the most recent version only

which is from 1 day ago i think

[little prism]

maybe most recent vscode extension

i can update and check again

[unborn blaze]

opened an issue about it

https://github.com/rust-lang/rust-analyzer/issues/21617

for now i will stick with the previous version

[little prism]

this isnt r-a's fault

this is vscode

try install normal r-a

rustup component add rust-analyzer

[unborn blaze]

i think i already have it

 ❯ rustup component list | grep rust-analyzer
rust-analyzer-x86_64-unknown-linux-gnu

[unborn blaze]

well, perhaps you're right, but isn't it the extension authors responsibility to make sure it works correctly?

and if what you're saying is true, then why downgrading fixes the problem?

[little prism]

this repo doesnt make the extension

"rust-analyzer.server.path": "rust-analyzer"

add this to your settings.json

this will use system r-a instead of bundled

might fix issues

[unborn blaze]

the extension provides a link for issues:

on the sidebar if you click on "issues" it sends you to that repository

[unborn blaze]

thanks, i will try it out right away

[little prism]

sorry

wait maybe they do also maintain the package

i just dont think its exactly a r-a issue

i think its vscode

i've had vscode issues before

[unborn blaze]

i think they do because when you try to open an issue, the template has some pre-filled spots for vscode and such

[little prism]

but no latest r-a works perfectly fine in nvim

[unborn blaze]

yeah def, i mean i have no idea what the issues is

so not trying to argue who's fault it is

hmmm

[unborn blaze]

i tried this, but now it won't even work since im getting different errors

i think

[little prism]

what kinds of errors

[unborn blaze]

maybe its because i don't have rust-analyzer itself installed properly

well for starters, i never explicitly installed it via rustup

❯ rust-analyzer
error: Unknown binary 'rust-analyzer' in official toolchain 'stable-x86_64-unknown-linux-gnu'.

Stack backtrace:
0: <unknown>
1: <unknown>
2: <unknown>
3: <unknown>
4: <unknown>
5: <unknown>
6: <unknown>
7: <unknown>
8: <unknown>
9: <unknown>
10: <unknown>
11: <unknown>
12: <unknown>
13: __libc_start_main
14: <unknown>

[little prism]

rustup component add rust-analyzer

you dont have it

[unborn blaze]

yep yep

any idea what is this though?

❯ rustup component list | grep rust-analyzer
rust-analyzer-x86_64-unknown-linux-gnu

ohh

i get it

[little prism]

hmm

[unborn blaze]

no no i understand

i thought the list command shows list of installed modules

but it shows list of available modules

now after i installed it:

❯ rustup component list | grep rust-analyzer
rust-analyzer-x86_64-unknown-linux-gnu (installed)

[little prism]

yeah no it isnt installed

[unborn blaze]

exactly

[little prism]

ok see if vscode works now

[unborn blaze]

i think it does, let me test the other project

[unborn blaze]

yes

it definitely fixes it i believe

thank you for the tip 👍

tell me, what are the odds of me running into this rabbit hole exactly the day i wanted to try clippy for the first time 😅

i better update the issue with this info

[little prism]

i dont know

but vscodes packaged r-a is eventually gonna break

i set it to use my system one on my pc as well

before i switched to nvim

[unborn blaze]

i do that for typescript and node too

to avoid certain issues

but i have near-zero famiiarity with the rust tooling so far so...

[little prism]

i just wouldnt suggest linting pedantic

it makes you need to spam #![expect] everywhere

[unborn blaze]

if it gets annoying i will remove it for sure

but i feel that it's good to have it on while learning

i mean, i haven't had much of a chance to even use it because i was dealing with the issue

[unborn blaze]

wouldn't in that case be easier to just disable certain rules rather than not using pedantic group?

like - use pedantic but disable the rules that get annoying

[little prism]

clippy on default settings is enough

lints get moved to pedantic for being opinionated or just throwing false positives

[unborn blaze]

when i was debugging the extension error earlier and i disabled the pedantic rules, it made a lot of the warnings go away, warnings that were actually useful and offered refactoring suggestions

[little prism]

yeah

can you run clippy -W pedantic in a terminal and paste the output here in a code block

[unborn blaze]

Here are a few:

warning: empty String is being created manually
  --> src/db.rs:64:28
   |
64 |         let mut contents = String::from("");
   |                            ^^^^^^^^^^^^^^^^ help: consider using: `String::new()`

warning: `format!(..)` appended to existing `String`
  --> src/db.rs:67:13
   |
67 |             contents.push_str(&format!("{key}:{value}\n"));
   |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

warning: redundant closure
   --> src/db.rs:103:30
    |
103 |         self.rows.keys().map(|s| s.as_str()).collect()
    |                              ^^^^^^^^^^^^^^ help: replace the closure with the method itself: `std::string::String::as_str

also, there was another really useful one, let me see if i remember

[little prism]

you can use W pedantic

but just dont set it as default in your lsp

if you want pedantic

you can add #![warn(clippy::pedantic)]

to the start of your code

[unborn blaze]

but why though, i still don't understand why it's such a problem, it lets me discover issues and ways to refactor.

1. it's opinionated, okay i get it
2. false-positive, i can deal with that

[little prism]

because you shouldnt set this as a cli argument

you should put these as
#[warn(xyz)]

in your lib.rs or main.rs

[unborn blaze]

you mean in "rust-analyzer.check.extraArgs": ["--", "-W", "clippy::all", "-W", "clippy::pedantic"], ?

[little prism]

yes

and also -W all is redundant

it already does

[unborn blaze]

what's the benefit of having these inside of files rather than in settings.json?

because if they are in settings.json they will apply for every project globally

[little prism]

yeah

and for some projects

they dont care about pedantic and you will get a crazy number of warnings

[unborn blaze]

ok

1. you can always create per-project config in .vscode/settings.json
2. i see your point now

you could have said that, and yeah i agree

the thing is, i haven't started making any real projects yet, still on chapter 15 of the book

[little prism]

but dont do #1

put it in your main rs

[unborn blaze]

yes, once i start working on more serious projects this is definitely the way to go 👍

[little prism]

so that anyone else using clippy outside the extension will also have -W pedantic

[unborn blaze]

agreed

actually

i might as well develop the good habit of doing that right away

but have to test how that works along with the extension

like if i dont pass extraArgs, will rust-analyzer pick the settings from main.rs

need to read/test

So i added #![warn(clippy::all, clippy::pedantic)] in my main.rs file and it seems the extension does pick it up.

I also tried disabling specific rules by adding this in Cargo.toml

[lints.clippy]
redundant_closure_for_method_calls = "allow"

though that doesn't seem to work unfortunately.

actually, running cargo clippy also seems to ignore that