Configuration

Source: config.rs

The Installation section contains details on configuration for some of the editors. In general rust-analyzer is configured via LSP messages, which means that it’s up to the editor to decide on the exact format and location of configuration files.

Some clients, such as VS Code or COC plugin in Vim provide rust-analyzer specific configuration UIs. Others may require you to know a bit more about the interaction with rust-analyzer.

For the latter category, it might help to know that the initial configuration is specified as a value of the initializationOptions field of the InitializeParams message, in the LSP protocol. The spec says that the field type is any?, but rust-analyzer is looking for a JSON object that is constructed using settings from the list below. Name of the setting, ignoring the rust-analyzer. prefix, is used as a path, and value of the setting becomes the JSON property value.

For example, a very common configuration is to enable proc-macro support, can be achieved by sending this JSON:

json

{
  "cargo": {
    "buildScripts": {
      "enable": true,
    },
  },
  "procMacro": {
    "enable": true,
  }
}

Please consult your editor’s documentation to learn more about how to configure LSP servers.

To verify which configuration is actually used by rust-analyzer, set RA_LOG environment variable to rust_analyzer=info and look for config-related messages. Logs should show both the JSON that rust-analyzer sees as well as the updated config.

(Work in progress:) It is also possible to place configuration in a rust-analyzer.toml file. It should be located in the project root or in your user configuration directory (e.g. ~/.config/rust-analyzer/). This is a work in progress, many configuration options aren't supported yet.

This is the list of config options rust-analyzer supports: