I was just doing a tiny bit of work on a project which ran into an issue using the most recent version of rust-analyzer, and realized that the solution is to make sure my editor uses the same version of the Rust toolchain as the project in question has specified — in its case, via a rust-toolchain.toml file. The solution in Zed’s case is pretty straightforward, thanks to a change earlier this year: specify the path you want in lsp.rust-analyzer.binary.path.

You can do that in project-specific settings like this:

{
  "lsp": {
    "rust-analyzer": {
      "binary": {
        "path": "/Users/chris/.cargo/bin/rust-analyzer"
      }
    }
  }
}

You could set the same in your application-wide settings… and you might want to. Why? Well, something interesting to notice about the path I set there is that it is not pointing to a specific version, but to ~/.cargo/bin/rust-analyzer. That is a symlink managed by rustup, and that symlink is actually just a pointer back to rustup itself. Under the hood, rustup will check what it was invoked as and where it was invoked from, and use that to dispatch to the right

That means it always matches whatever the appropriate version of a given tool — rustc, cargo, or (as here) rust-analyzer is for the directory in question. That means if you like you can set up Zed to always use the version of rust-analyzer that was bundled with the version you are using in a given project, by putting those lsp settings in your editor-wide configuration instead of just your project configuration. Neat!

One downside here is you will not get new features or bug fixes for rust-analyzer. The big upside is that anything that worked when you chose that version of Rust will continue to work, even if a newer version rust-analyzer drops support for older versions.