ditch crate2nix, use fenix instead of oxalica/rust-overlay

flake.nix

@@ -4,14 +4,10 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     utils.url = "github:numtide/flake-utils";
-    rust-overlay.url = "github:oxalica/rust-overlay";
-    crate2nix = {
-      url = "github:kolloch/crate2nix";
-      flake = false;
-    };
+    fenix.url = "github:nix-community/fenix";
   };
 
-  outputs = { self, nixpkgs, utils, rust-overlay, crate2nix }: let
+  outputs = { self, nixpkgs, utils, fenix }: let
     name = "poop-graph";
   in
     utils.lib.eachDefaultSystem
@@ -19,22 +15,13 @@
         let
           pkgs = import nixpkgs {
             inherit system;
-            overlays = [
-              rust-overlay.overlays.default
-              (final: prev: {
-                rustc = final.rust-bin.stable.latest.default;
-                cargo = final.rust-bin.stable.latest.default;
-              })
-            ];
+            overlays = [ fenix.overlays.default ];
+          };
+          fenixStable = fenix.packages.${system}.stable;
+          fenixPlatform = pkgs.makeRustPlatform {
+            cargo = fenixStable.toolchain;
+            rustc = fenixStable.toolchain;
           };
-          inherit (import "${crate2nix}/tools.nix" { inherit pkgs; })
-            generatedCargoNix;
-          project = import
-            (generatedCargoNix {
-              inherit name;
-              src = ./.;
-            })
-            { inherit pkgs; };
         in rec {
           packages.${name} = pkgs.symlinkJoin {
             inherit name;
@@ -48,11 +35,25 @@
 
           defaultPackage = packages.${name};
 
-          packages."${name}-unwrapped" = project.rootCrate.build;
+          packages."${name}-unwrapped" = let
+            cargoTOML = builtins.fromTOML (builtins.readFile ./Cargo.toml);
+          in fenixPlatform.buildRustPackage {
+            pname = name;
+            inherit (cargoTOML.package) version;
+            src = ./.;
+            cargoLock.lockFile = ./Cargo.lock;
+          };
 
-          devShell = pkgs.mkShell {
-            nativeBuildInputs = with pkgs; [ rustc cargo cargo-audit stdenv.cc ];
-            RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";
+          devShell = with pkgs; let
+            fenixWith = fenixStable.withComponents [
+              "cargo"
+              "clippy"
+              "rust-src"
+              "rustc"
+              "rustfmt"
+            ];
+          in mkShell {
+            nativeBuildInputs = [ fenixWith cargo-audit stdenv.cc ];
           };
         }
       );