"duplicated RLS configuration" each time RLS is started inside VSCode

Question

I upgraded my Rust environment via rustup update recently, then my VSCode reports an error each time I open my editor. Two repeated windows pop up at the bottom right corner of the editor, showing that

Duplicated RLS configuration: rustfmt_path:rustfmt_path,rustfmt_path,,
Source: Rust (rls) (Extension)

I can open VSCode's default settings.json and indeed find duplicated entries, but I'm not able to delete them.

Restarting the extension can reproduce the problem, and I don't even know if the plugin itself is working properly or not.

Answer 1

I've been through the same problem. I am not exactly sure of the proper solution but these workarounds have solved my problem.

1. Remove all VSCode extensions that are Rust-related.
2. Remove any Rust-related configuration in VSCode settings.json.
3. If you are using Linux and you have done a lot of playing around, sometimes $HOME/.cargo/registry may be corrupt, so remove that folder if it helps.
4. Restart VSCode.

5. Install these extensions in order:

   • Rust RLS official extension

     Do not install Rust kalitaalexey (Seems to be the conflicting cause).

   • Rust Assist extension.

   • vscode-rust-syntax extension.

   • vsc-rustfmt extension.

   • Cargo extension.

   • Better TOML

The combination of these extensions work OK for me. Specifically, the syntax formatting works with Ctrl+Shift+I and saving the file automatically does that.

One last hint: Opening 2 Rust project folders in VSCode at the same time may cause an error message that states Unable to find root directory. Try to avoid that.