How to configure to attach a rust lsp client for single file

[lost22git]

No description provided.

[kirawi]

It's not supported rust-lang/rust-analyzer#6388

[anstadnik]

It is though rust-lang/rust-analyzer#8955

[rcorre]

@anstadnik how do you actually use the feature you linked? The PR doesn't explain it, and it doesn't seem to work out-of-the-box (running rust-analyzer 1 (af40101841 2024-01-07))

[anstadnik]

I used https://github.com/simrat39/rust-tools.nvim, which supports the standalone feature. I'm not the developer, so I can't tell you how it uses the feature.

[rcorre]

Ah, I'd assumed you had it working in Helix

[the-mikedavis]

You can use rust-analyzer with non-cargo projects like single files but you need to tell rust-analyzer about the project with a rust-project.json file: https://rust-analyzer.github.io/manual.html#non-cargo-based-projects

[chaoky]

you could use rust-project.json before that pr, this what using that feature looks like in neovim:

local lsp_conf = require('lspconfig')

lsp_conf.rust_analyzer.setup {
    -- Other setup stuff
    -- ...

    -- To be able to start rust-analyzer at all a root_dir is needed,
    -- I added a star match for testing purposes to match on any file
    -- This could be an lspconfig/Neovim only issue
    root_dir = lsp_conf.util.root_pattern("*"),

    -- LSP Client needs to know the detached files ahead of time on
    -- initialization and pass them to the r-a on startup
    init_options = { detachedFiles = { "/tmp/file.rs" } }
}

from: rust-lang/rust-analyzer#14318 (comment)
the cargo script rfc was merged, so this is probably just a stop gap: rust-lang/rust-analyzer#15318