Attempt at packagin kani with fenix https://github.com/model-checking/kani

flake.lock

{
  "nodes": {
    "fenix": {
      "inputs": {
        "nixpkgs": [
          "nixpkgs"
        ],
        "rust-analyzer-src": "rust-analyzer-src"
      },
      "locked": {
        "lastModified": 1701066187,
        "narHash": "sha256-WP2sUVcjM4uuCBnw2r++6Rnuqzd4iZ7oh/o7AarPjIM=",
        "owner": "nix-community",
        "repo": "fenix",
        "rev": "bec77b7f219319a49dc1885490236714b023d19c",
        "type": "github"
      },
      "original": {
        "owner": "nix-community",
        "repo": "fenix",
        "type": "github"
      }
    },
    "nixpkgs": {
      "locked": {
        "lastModified": 1700794826,
        "narHash": "sha256-RyJTnTNKhO0yqRpDISk03I/4A67/dp96YRxc86YOPgU=",
        "owner": "NixOS",
        "repo": "nixpkgs",
        "rev": "5a09cb4b393d58f9ed0d9ca1555016a8543c2ac8",
        "type": "github"
      },
      "original": {
        "owner": "NixOS",
        "ref": "nixos-unstable",
        "repo": "nixpkgs",
        "type": "github"
      }
    },
    "root": {
      "inputs": {
        "fenix": "fenix",
        "nixpkgs": "nixpkgs",
        "systems": "systems"
      }
    },
    "rust-analyzer-src": {
      "flake": false,
      "locked": {
        "lastModified": 1700997114,
        "narHash": "sha256-pOz99NESIGosyt19tqNw7gfS6NQJtFY0kGF3rFV0bZ0=",
        "owner": "rust-lang",
        "repo": "rust-analyzer",
        "rev": "237712fa314237e428e7ef2ab83b979f928a43a1",
        "type": "github"
      },
      "original": {
        "owner": "rust-lang",
        "ref": "nightly",
        "repo": "rust-analyzer",
        "type": "github"
      }
    },
    "systems": {
      "locked": {
        "lastModified": 1681028828,
        "narHash": "sha256-Vy1rq5AaRuLzOxct8nz4T6wlgyUR7zLU309k9mBC768=",
        "owner": "nix-systems",
        "repo": "default",
        "rev": "da67096a3b9bf56a91d16901293e51ba5b49a27e",
        "type": "github"
      },
      "original": {
        "owner": "nix-systems",
        "repo": "default",
        "type": "github"
      }
    }
  },
  "root": "root",
  "version": 7
}

flake.nix

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    systems.url = "github:nix-systems/default";
    fenix = {
      url = "github:nix-community/fenix";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };

  nixConfig = {
    extra-trusted-public-keys = "devenv.cachix.org-1:w1cLUi8dv3hnoSPGAuibQv+f9TZLr6cv/Hm9XgU50cw=";
    extra-substituters = "https://devenv.cachix.org";
  };

  outputs = { self, nixpkgs, systems, fenix } @ inputs:
    let
      forEachSystem = nixpkgs.lib.genAttrs (import systems);
    in
    {
      packages = forEachSystem
        (system:
          let
            pkgs = import nixpkgs {
              inherit system;
              overlays = [
                fenix.overlays.default
              ];
            };
            fenixToolchain = pkgs.fenix.complete;
          in
          {
            kaniFenix = pkgs.callPackage ./kani.nix {
              inherit (fenixToolchain) rust-src rustc-dev llvm-tools-preview toolchain;
              rustPlatform = pkgs.makeRustPlatform {
                cargo = fenixToolchain.toolchain;
                rustc = fenixToolchain.toolchain;
              };
            };

            kaniNixpkgs = pkgs.callPackage ./kani.nix {
              toolchain = pkgs.rustPlatform.rustLibSrc;
              rust-src = pkgs.rustPlatform.rustLibSrc;
              rustc-dev = "";
            };

            kaniFhs = pkgs.callPackage ./kani-fhs.nix { };
          });
    };
}

kani-fhs.nix

{
  buildFHSEnv,
  rustup,
  rustc,
  cargo,
  gcc,
  python3,
}:

buildFHSEnv {
  name = "kani-env";
  targetPkgs = _pkgs: [
    rustup
    rustc
    cargo
    gcc
    (python3.withPackages (pp: [
      pp.pip
    ]))
  ];
  multiPkgs = null;
  runScript = ''
    sh -c '
      export HOME=/tmp/kani-home
      if [[ ! -d "$HOME" ]]; then
        mkdir -p "$HOME"
        rustup default stable
        cargo install --locked kani-verifier
        cargo kani setup
      fi
      exec ''${SHELL:bash}
    '
  '';
}

kani.nix

{ lib
, rustPlatform
, fetchFromGitHub
, toolchain
, rust-src
, rustc-dev
}:

rustPlatform.buildRustPackage rec {
  pname = "kani";
  version = "0.41.0";

  src = fetchFromGitHub {
    owner = "model-checking";
    repo = "kani";
    rev = "kani-${version}";
    hash = "sha256-egxEh97LXJDI9PtECxls0pok7ElF/bjri+KhCSR9o8c=";
  };

  cargoHash = "sha256-ow/ioCQ4cGFKEzn3WI8Fi4sBXgGchTXA+/Myv5rnZF0=";

  env = lib.traceValSeq {
    # kani-compiler expects Nightly compiler installed through rustup.
    RUSTUP_HOME = "${toolchain}";
    RUSTUP_TOOLCHAIN = "..";
    # Allow nightly features on stable compiler.
    RUSTC_BOOTSTRAP = 1;

    # RUST_SRC_PATH = "${rust-src}/lib/rustlib/src/rust/library";
    # RUST_SRC_PATH = "${rustc-dev}/lib/rustlib/rustc-src/rust/compiler";
  };

  meta = with lib; {
    description = "Kani Rust Verifier";
    homepage = "https://github.com/model-checking/kani";
    changelog = "https://github.com/model-checking/kani/blob/${src.rev}/CHANGELOG.md";
    license = with licenses; [ asl20 mit ];
    maintainers = with maintainers; [ jtojnar ];
    mainProgram = "kani";
  };
}