autocomplete not working with cmp, even though it works with every other language(on NixOS)?

[DrTeagle]

Howdy,
I am having an issue with autocomplete not showing up, maybe I am misunderstanding the capabilities, but everything else works, code actions works, and RustLsp logFile shows this:

2024-09-25T23:47:35.158808Z ERROR Flycheck failed to run the following command: CommandHandle { program: "/nix/store/a04bnqgj3mvg777a70jymwnxcgm7cdcv-rustup-1.27.1/bin/cargo", arguments: ["clippy", "--workspace", "--message-format=json-diagnostic-rendered-ansi", "--manifest-path", "/home/cdockter/Documents/CodingProjects/rustprojects/branches/Cargo.toml", "--keep-going", "--all-targets", "--all-features", "--no-deps"], current_dir: Some("/home/cdockter/Documents/CodingProjects/rustprojects/branches") }, error=Cargo watcher failed, the command produced no valid metadata (exit code: ExitStatus(unix_wait_status(256))):
error: 'cargo-clippy' is not installed for the custom toolchain '/nix/store/p024jn1sd4pn33lg0kaqxh7j2sp1iw7x-rustc-1.80.1'.
note: this is a custom toolchain, which cannot use `rustup component add`
help: if you built this toolchain from source, and used `rustup toolchain link`, then you may be able to build the component with `x.py`

2024-09-25T23:47:35.469745Z ERROR Flycheck failed to run the following command: CommandHandle { program: "/nix/store/a04bnqgj3mvg777a70jymwnxcgm7cdcv-rustup-1.27.1/bin/cargo", arguments: ["clippy", "--workspace", "--message-format=json-diagnostic-rendered-ansi", "--manifest-path", "/home/cdockter/Documents/CodingProjects/rustprojects/branches/Cargo.toml", "--keep-going", "--all-targets", "--all-features", "--no-deps"], current_dir: Some("/home/cdockter/Documents/CodingProjects/rustprojects/branches") }, error=Cargo watcher failed, the command produced no valid metadata (exit code: ExitStatus(unix_wait_status(256))):
error: 'cargo-clippy' is not installed for the custom toolchain '/nix/store/p024jn1sd4pn33lg0kaqxh7j2sp1iw7x-rustc-1.80.1'.
note: this is a custom toolchain, which cannot use `rustup component add`
help: if you built this toolchain from source, and used `rustup toolchain link`, then you may be able to build the component with `x.py`

however I do not think that these errors would cause autocomplete to stop working? i have autocomplete with every other language and have commented out my rustaceanvim config and it still seems to not work. I am not calling lspconfig at all to my knowledge. I am at a loss here. any pointers to fix this issue would be great. I have looked at similair discussions. and this is my capabilities block:

M.capabilities = require("cmp_nvim_lsp").default_capabilities(vim.lsp.protocol.make_client_capabilities())

M.capabilities.textDocument.completion.completionItem = {
	documentationFormat = { "markdown", "plaintext" },
	snippetSupport = true,
	preselectSupport = true,
	insertReplaceSupport = true,
	labelDetailsSupport = true,
	deprecatedSupport = true,
	commitCharactersSupport = true,
	tagSupport = { valueSet = { 1 } },
	resolveSupport = {
		properties = {
			"documentation",
			"detail",
			"additionalTextEdits",
		},
	},
}

when I call this and have no other config it still doesnt seem to work, i apologize profusely if there is a trivial solution.

[mrcjkb]

hey 👋

rustaceanvim auto-detects cmp_nvim_lsp and registers the capabilities, so you shouldn't need to do that manually. Although I doubt that's what's causing your issue.

It's most likely related to your project or rust-analyzer build.
Do you have a minimal flake that you can reproduce it with?
I also provide a derivation with a minimal config for Nix users. See the troubleshooting section.

[DrTeagle]

this is the flake I used for the dev shell:

{
  description = "rustacean flake";
  inputs = {

    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    rustacean.url = "github:mrcjkb/rustaceanvim";
  };
  outputs = { self, nixpkgs, rustacean, ... }@inputs:
    let
      system = "x86_64-linux";
      pkgs = import nixpkgs { inherit system; };
    in
    {
      devShells.${system}.default = pkgs.mkShell
        {
          buildInputs = with pkgs;[
            clang
            libclang
            rocmPackages_6.llvm.clang-unwrapped
            libgcc
            glib
            gcc-unwrapped
            llvm_18
            pkg-config
            clang-tools
            rustacean.packages.${system}.codelldb
            rustc
            rustup
            rustfmt
            rust-analyzer
            cargo
          ];
          shellHook = ''
            rustup default stable
            rustup component add clippy
            export PATH="$HOME/.cargo/bin:$PATH"
            export PATH="$PATH:${rustacean.packages.${system}.codelldb}/bin"
            export PATH="${pkgs.rust-analyzer}/bin:$PATH"
            export PATH="$PATH:${pkgs.rustfmt}/bin"
          '';
        };
    };
}

and I used the nix run on nightly and there was still no autocomplete

[mrcjkb]

That's not how I would set up a devShell for rust development. You shouldn't use rustup when using Nix. That sounds like a recipe for conflicts.
And there's no need to set up the PATH manually for packages in the devShell's buildInputs.

and I used the nix run on nightly and there was still no autocomplete

For autocomplete you'll have to enable Neovim's built-in autocompletion or add a plugin for it to the package.

[DrTeagle]

I have this minimal.lua and I see no auto complete:

vim.env.LAZY_STDPATH = ".repro"
load(vim.fn.system("curl -s https://raw.githubusercontent.com/folke/lazy.nvim/main/bootstrap.lua"))()

require("lazy.minit").repro({
	spec = {
		{
			"hrsh7th/nvim-cmp",
			lazy = false,
		},
		{
			"hrsh7th/cmp-nvim-lsp",
			lazy = false,
		},
		{
			"mrcjkb/rustaceanvim",
			version = "^5",
			init = function()
				-- Configure rustaceanvim here
				vim.g.rustaceanvim = {}
			end,
			lazy = false,
		},
	},
})

also for the flake more tips on how to write it would be much appreciated, I am rather new to making dev shells with flakes.

[mrcjkb]

I have this minimal.lua and I see no auto complete:

nvim-cmp doesn't work if you don't call its setup function.

also for the flake more tips on how to write it would be much appreciated, I am rather new to making dev shells with flakes.

• Here's an example of a rust project with a nix devShell.
• Here's the template I use for creating a basic rust devShell.

Instead of pkgs for your rust toolchain (cargo, rustc, ...), I recommend using pkgs.rustPlatform.

In general, there's not much I can do to help you when it comes to problems with autocompletion, because rustaceanvim doesn't implement autocompletion.
So the way to troubleshoot this is by bisecting your other plugins and troubleshooting your rust toolchain.

[DrTeagle]

figured it out cant reprouduce with minimal config. I called init for lazy and autocomplete works, marking this as closed

[jrray]

In case it helps anyone out there, I wasn't getting rust completions until I added this explicit dependency in my (lazy) configuration:

return {
    "mrcjkb/rustaceanvim",
    version = "^5", -- Recommended
    lazy = false,   -- This plugin is already lazy
    dependencies = {
        { "hrsh7th/cmp-nvim-lsp" },   -- <-- added this
    }
}