The rust-analyzer VS Code extension should automatically download the corresponding server binary according to the toolchain file instead of warning about it

[KSXGitHub]

Workspace .../Cargo.toml is using an outdated toolchain version 1.89.0 but rust-analyzer only supports 1.90.0 and higher.
Consider using the rust-analyzer rustup component for your toolchain or
upgrade your toolchain to a supported version.

This error is very annoying.

The extension should have loaded the corresponding rust-analyzer component according to the version specified in the rust-toolchain file.

Fixing the above warning requiring creating a local .vscode/settings.json and manually set the server path to the local component. This too is very annoying.

[ShoyuVanilla]

That might be a good feature to have, but implementing that requires non-trivial amount of complexities.

• We need some remote registry to host the binaries for each platforms
• The API between vs-code extension and the rust-analyzer binary takes breaking changes from time to time. We have to define and resolve compatibilities

BTW, we have adjusted the minimul supported version back to 1.78.0 with #21241 and that will be released with the stable channel next week.

[ChayimFriedman2]

I don't think we want to manage this complexity, when rustup can do it well already.

[KSXGitHub]

I don't think we want to manage this complexity, when rustup can do it well already.

Even after rustup has already downloaded the rust-analyzer component, the extension still displays the warning. Only after the server path has been manually overwritten to the exact path to the component will the extension stop complaining.

I don't think the user wants to repeat the aforementioned action for 100 projects.

[ShoyuVanilla]

If you want to use the rustup installed rust-analyzer, I think setting rust-analyzer.server.path to ~/.cargo/bin/rust-analyzer as a vs-code global configuration instead of per-workspace would work as the rustup proxy resolves the actual path for each toolchain per workspace.

[KSXGitHub]

@ShoyuVanilla Except it doesn't exist:

$ stat ~/.cargo/bin/rust-analyzer                                                    
stat: cannot statx '.../.cargo/bin/rust-analyzer': No such file or directory

[ShoyuVanilla]

Have you installed rust-analyzer with rustup?

https://rust-lang.github.io/rustup/concepts/index.html?#how-rustup-works

[KSXGitHub]

@ShoyuVanilla

$ rustup component add rust-analyzer   
info: component 'rust-analyzer' for target 'x86_64-unknown-linux-gnu' is up to date

[ShoyuVanilla]

I have no idea why you don't have rustup proxies under your $CARGO_HOME/bin/ but anyway, since rust-analyzer would exist in your $PATH as rustup proxy because you have installed it as a rustup component, I think setting rust-analyzer.server.path to rust-analyzer would work

[KSXGitHub]

There is actually /usr/lib/rustup/bin/rust-analyzer -> /usr/bin/rustup.

Still, I think it's pretty inconvenient for the extension to only work with the latest toolchain.

When the server path was not set, I think the extension should at least attempt to find system rust-analyzer on its own. Then maybe run rust-analyzer --version to check for compatibility.

If maintaining the compatibility between the rust-analyzer binary and the JavaScript extension proves too much effort, maybe even the JS extension should be managed by rustup as well?

[ShoyuVanilla]

Still, I think it's pretty inconvenient for the extension to only work with the latest toolchain.

No, it isn't the latest toolchain. It is redirected into the matching toolchain per workspace by rustup.

If maintaining the compatibility between the rust-analyzer binary and the JavaScript extension proves too much effort, maybe even the JS extension should be managed by rustup as well?

Managing the vs-code Typescript extension via rustup doesn't make sense much because

• It is vs-code (or some of its forks) only client so people using other editors such as Zed, emacs, vim or helix won't need it
• Even for vs-code itself, rustup cannot put rust-analyzer into its extension installation path

[KSXGitHub]

No, it isn't the latest toolchain. It is redirected into the matching toolchain per workspace by rustup.

That was what I believed. But the extension still printed the warning simply because my rust-toolchain file specified version 1.89.0 instead of the latest 1.90.0. The warning did not go away even after I did rustup component add rust-analyzer and restart the editor.

[ChayimFriedman2]

Interesting, do we start r-a in the project directory?