How can you use nightly rustfmt?

[ethanuppal]

Checked other resources

• This is not a bug report or feature request (Please use issues for those).
• This is a question about rustaceanvim, not rust-analyzer or Neovim.
• This is not a question about autocompletion.
• I have read the README.
• I have read the FAQ.
• I have searched for a solution using :h rustaceanvim.
• I have searched existing discussions.
• I have searched the existing issues/discussions of other plugins related to this question (if applicable).
• I have searched the existing rust-analyzer discussions (if applicable).
• I have added a very descriptive title to this question.

Description

I'm trying to format my files with nightly rustfmt. Instead, I have to remember to run cargo +nightly fmt manually. I tried

vim.g.rustfmt_command = "rustup run nightly rustfmt"

as well as specifying

                            rustfmt = {
                                extraArgs = {
                                    "+nightly",
                                },
                            },

but I don't think either of them are valid ways of specifying it.

Example Code

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 = {
    {
      'mrcjkb/rustaceanvim',
      version = '^5',
      init = function()
        -- Configure rustaceanvim here
        vim.g.rustaceanvim = {}
      end,
      lazy = false,
    },
  },
}

Neovim version (nvim -v)

v0.10.3

Operating system/version

macOS 14.7.4

Output of :checkhealth rustaceanvim

==============================================================================
rustaceanvim: require("rustaceanvim.health").check()

Checking for Lua dependencies ~
- OK optional dependency nvim-dap not installed. Needed for debugging features [mfussenegger/nvim-dap](https://github.com/mfussenegger/nvim-dap)

Checking external dependencies ~
- OK rust-analyzer: found rust-analyzer 1.85.0 (4d91de4e 2025-02-17)
- OK Cargo: found cargo 1.85.0 (d73d2caf9 2024-12-31)
- OK rustc: found rustc 1.85.0 (4d91de4e4 2025-02-17)
- ERROR       cargo-nextest: not found: Unsuported version. Required >=0.9.81, but found cargo-nextest 0.9.70
  
        rustaceanvim requires [cargo-nextest](https://nexte.st).
              Next generation test runner for Rust projects.
        Optional dependency, required if the 'tools.enable_nextest' option is set.
      
        

Checking config ~
- OK No errors found in config.

Checking for conflicting plugins ~
- OK No conflicting plugins detected.

Checking for tree-sitter parser ~
- OK tree-sitter parser for Rust detected.

[mrcjkb]

Hey 👋
Formatting is handled by rust-analyzer, so I recommend you ask there. If it's possible then likely via a rust-analyzer configuration option.

[ethanuppal]

Yes, I mean I looked at the config options for how rust-analyzer can invoke rustfmt

[mrcjkb]

I see. I would still suggest opening a discussion in the rust-analyzer repo.
Otherwise, there might also be something you could do in a .rustfmt.toml.

[madelaney]

@ethanuppal , I'm curious if you ever got around to this? I also use nightly toolchain for formatting, and my formatting is broken at the moment.

At one point, this worked, but no longer (just as a point of reference)

{
    'mrcjkb/rustaceanvim',
    version = '^6',
    ft = { 'rust' },
    init = function()
      vim.g.rustaceanvim = {
        server = {
          settings = {
            ['rust-analyzer'] = {
              rustfmt = {
                extraArgs = { '+nightly', '--unstable-features' },
              },
            },
          },
        },
      }
    end,
  },

[ethanuppal]

No, unfortunately not. I think this is trivial to implement, and it can probably be done with conform.nvim, but I've been too lazy to fix my config haha. So I just annoyingly keep doing a cargo +nightly fmt before I need to merge a PR. Average neovim papercut 😆

[frangio]

At one point, this worked, but no longer

Does anyone know why it stopped working?

[iampi31415]

@ethanuppal @frangio I tried the config frangio posted above and seems to work? This is in my pluglins/core.lua for LazyVim:

return {
  { "folke/lazy.nvim", version = false },
  {
    "LazyVim/LazyVim",
    opts = {
      colorscheme = "tokyonight",
    },
  },
  {
    "mrcjkb/rustaceanvim",
    version = "^6",
    lazy = false,
    ft = { "rust" },
    server = {
      settings = {
        ["rust-analyzer"] = {
          rustfmt = {
            extraArgs = { "+nightly", "--unstable-features" },
          },
        },
      },
    },
  },
}

I did run cargo +nightly fmt once, but still seems to work afterwards.

My .rustfmt.toml is:

reorder_imports = true
imports_granularity = "Crate"
group_imports = "StdExternalCrate"
reorder_modules = true

[ethanuppal]

I'll try this later today and let you know. Thanks!