> I created an overlay which mimic rustup behaviour, and allow you to spawn a nix-shell with the latest nightly, beta, or stable version of rustc & cargo.
> To use this overlay, checkout nixpkgs-mozilla [1], and create a symbolic link to the file rust-overlay.nix [2] in the ~/.config/nixpkgs/overlays
Ok, so whenever you want to use a newer rust, you just git pull this thing and ...
> This overlay should auto-update it-self as if you were running rustup each time you go through the rustChannels attributes. It works by using the fetchurl builtin function to pull the same file as rustup do through https.