rust fmt

VS Code extension for formatting Rust code with rustfmt.

Supports:

• File formatting (including format on save)
• Workspace formatting (cargo fmt-optimized)
• Git-aware formatting (changed / staged Rust files)
• Status bar + Control Center quick actions
• Native macro_rules! body formatting
• Standalone binary usable from Vim / Neovim without a plugin

Marketplace

Requirements

rustup component add rustfmt

Works on Linux, Windows, macOS.

Settings

Set as default formatter in settings.json:

"[rust]": {
    "editor.defaultFormatter": "vremyavnikuda.rust-fmt",
    "editor.formatOnSave": true
}

Delete blank lines inside braces:

"rustfmt.compactBlankLines": true

Commands

Vim / Neovim

The macro formatter is a plain stdin-to-stdout filter, so no plugin is needed.

Install

Linux and macOS:

curl -fsSL https://raw.githubusercontent.com/vremyavnikuda/rust-fmt/main/install.py | python3 -

Windows, in PowerShell:

irm https://raw.githubusercontent.com/vremyavnikuda/rust-fmt/main/install.py | python -

One script for all three systems. It needs Python 3.8 or newer, which most Linux installs already have and which macOS and Windows get from python.org or their package manager.

The binary goes in ~/.local/bin and its SHA-256 is checked against the one published with the release. On Linux and macOS the script prints the line to add to your shell config; on Windows it adds the directory to your user PATH itself, so open a new terminal afterwards. RUSTFMT_MF_VERSION pins a release instead of the latest, RUSTFMT_MF_BIN_DIR installs somewhere else.

chmod +x rust-fmt-mf

cargo install --git https://github.com/vremyavnikuda/rust-fmt rust-fmt-mf

Vim

autocmd FileType rust setlocal formatprg=rust-fmt-mf\ --edition\ 2021

Format the buffer with gggqG, or a selection with gq. A selection has to hold whole items, such as complete functions; part of one is left unchanged, because the formatter cannot parse it on its own. If formatting fails for any reason, the lines come back exactly as they were.

Neovim with conform.nvim

Preferred over formatprg: it keeps the cursor position and marks, and gives you format-on-save.

require("conform").setup({
  formatters = {
    ["rust-fmt-mf"] = {
      command = "rust-fmt-mf",
      args = { "--edition", "2021" },
      stdin = true,
    },
  },
  formatters_by_ft = { rust = { "rust-fmt-mf" } },
  format_on_save = { timeout_ms = 2000, lsp_format = "never" },
})

Options

rustfmt.toml and rust-toolchain.toml are picked up from the working directory upwards without any flags — rustfmt searches for its own config, and the rustup shim resolves the pinned toolchain the same way. Keep your editor's working directory inside the project and both just work.

The edition is the exception: it has to be in your editor config, because the formatter reads from stdin and never learns the file's path. A crate on a different edition fails loudly with a rustfmt parse error rather than producing wrong output — change the --edition value to match.

How it works

Runs rustfmt --emit stdout with auto-detected crate root, edition, and config. The edition comes from [package] in the nearest Cargo.toml, following edition.workspace = true to the workspace root. When macroFormatter.native is enabled, formats macro_rules! bodies via rust-fmt-mf (skipped by standard rustfmt).

Also detects rust-toolchain and rustfmt.toml, skips files over 2 MB.

Troubleshooting

• rustfmt not found: run rustup component add rustfmt or set rustfmt.path.
• Format Selection changes nothing: the selected lines cannot be formatted apart from the rest of the file, usually because rustfmt would move an import elsewhere. The log says so; format the whole document instead.