emacs VS fenix

You may be interested in my flake: https://github.com/cmacrae/emacs

Rustup works as is. Though note that Nix supplants all such toolchain installers such as Rustup, nvm, etc. I.e. instead of Rustup there is fenix.

Fenix ( https://github.com/nix-community/fenix ) has tooling or picking a specific toolchain or even nightly. You can then build with the following nix code:

Fenix monthly is a new branch similar to the main branch, but only updated on the 1st of every month, for cases where you want to use rust nightly but don't need it to be updated very often.

The issue should be fixed once the nix-vscode-extension and fenix patches are merged. The latter will happen automatically once CI passes.

4. I would suggest Mozilla's Rust overlay or fenix or similar instead of Rustup - that would be more of the "Nix-way" to acquire the toolchain and you can still manage multiple versions. Not sure what the Ruby equivalent is, I don't do Ruby.

To follow along, you'll need a stable Rust toolchain. See the install page for instructions to install rustup for your platform. You should prefer this method to your distribution's package manager. If you're a NixOS freak, I recommend fenix.