Simplest setup for nvim and rust and system rust-analyzer

Question

All the tutorials that I found to use nvim with rust-analyzer either suggest using Packer (which is unmaintained since August), vim plugin managers (I really want to avoid anything vimscript, it's hideous) or using mason-lspconfig which downloads its own rust-analyzer (a total dealbreaker, since a rust-analyzer decoupled from the rustc I actually use can cause plenty of issues, especially because I use nightly a lot).

What is the simplest config I need to have to setup Rust LSP in nvim using only lua, maintained plugin installer and the system rust-analyzer?

Note: I'm a complete nvim beginner, other than the location .config/nvim/nvim.lua and regular vim stuff, I know nothing. I believe (possibly it's improperly installed) I was able to successfully install treesitter using lazy.nvim.

Answer 1

Following the installation instructions for the Lazy plugin manager, place the following in ~/.config/nvim/init.lua:

local lazypath = vim.fn.stdpath("data") .. "/lazy/lazy.nvim"
if not vim.loop.fs_stat(lazypath) then
  vim.fn.system({
    "git",
    "clone",
    "--filter=blob:none",
    "https://github.com/folke/lazy.nvim.git",
    "--branch=stable", -- latest stable release
    lazypath,
  })
end
vim.opt.rtp:prepend(lazypath)

-- Load plugins from lua/plugins.lua
require('lazy').setup('plugins')

Then the following Rust-related plugins should get you started:

• rust.vim for syntax highlighting, formatting
• rustaceanvim for LSP integration

Adding these to ~/.config/nvim/lua/plugins.lua:

return {
    { 'rust-lang/rust.vim' },
    {
        'mrcjkb/rustaceanvim',
        version = '^3',
        ft = { 'rust' },
    }
}

You can confirm this is using your system LSP via :checkhealth rustaceanvim after opening a Rust file:

Checking external dependencies
- OK rust-analyzer: found rust-analyzer 1.75.0 (82e1608 2023-12-21)

If instead you had accidentally installed Mason's rust-analyzer, this check would say something like

- OK rust-analyzer: found rust-analyzer 0.3.1799-standalone

In that event you could remove the Mason version with :MasonUninstall rust-analyzer.