lsp-cargo-feature-switcher

An Emacs package for interactively toggling Cargo features in Rust projects via LSP configuration.

2025-10-16.16-40-16.webm

Features

• Find and parse Cargo.toml files
• Interactive menu to toggle Cargo features
• Automatically updates .dir-locals.el with LSP configuration
• Shows enabled features and their dependencies
• Supports toggling no-default-features
• Supports both eglot and lsp-mode

Dependencies

Requires tomlparse.el, a tree-sitter based TOML parser that requires Emacs 29.1 or later.

Usage

Run M-x cargo-features-toggle-menu to open the interactive feature selection menu.

Configuration

By default, the package uses eglot mode. To switch to lsp-mode, set:

(setq cargo-features-lsp-mode 'lsp-mode)

Eglot Mode (default)

When using eglot, the .dir-locals.el file is created at the project root (directory containing .git) with configuration in the format:

((rustic-mode . ((eglot-workspace-configuration
                  . (:rust-analyzer
                     (:cargo (:features ["feature1" "feature2"]
                              :noDefaultFeatures t)))))))

LSP Mode

When using lsp-mode, the .dir-locals.el file is created at the Cargo.toml directory with configuration in the format:

((rustic-mode . ((lsp-rust-features . ["feature1" "feature2"])
                 (lsp-rust-no-default-features . t))))