Custom Rust version

flake.nix

{
  inputs = {
    nixpkgs.url = github:NixOS/nixpkgs/nixos-22.05;
    flake-utils.url = github:numtide/flake-utils;
    rust-overlay.url = github:oxalica/rust-overlay;
  };

  outputs = { self, nixpkgs, flake-utils, rust-overlay }:
    flake-utils.lib.simpleFlake {
      inherit self nixpkgs;
      name = "Rust environment";
      preOverlays = [rust-overlay.overlays.default];
      shell = ./shell.nix;
    };
}

shell.nix

{ pkgs }:
with pkgs;
let rust = rust-bin.stable."1.62.0".default.override {
      extensions = [ "rust-src" ];
    };
in mkShell {
  packages = [
    clang
    cmake
    libclang
    perl
    pkg-config
    protobuf
    rust
  ];

  shellHook = ''
    export LIBCLANG_PATH="${libclang.lib}/lib"

    echo
    echo shell.nix: loaded
    echo
  '';
}