diff --git a/flake.lock b/flake.lock
index dda24e9..1720cb2 100644
--- a/flake.lock
+++ b/flake.lock
@@ -1,30 +1,12 @@
 {
   "nodes": {
-    "flake-utils": {
-      "inputs": {
-        "systems": "systems"
-      },
-      "locked": {
-        "lastModified": 1705309234,
-        "narHash": "sha256-uNRRNRKmJyCRC/8y1RqBkqWBLM034y4qN7EprSdmgyA=",
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "rev": "1ef2e671c3b0c19053962c07dbda38332dcebf26",
-        "type": "github"
-      },
-      "original": {
-        "owner": "numtide",
-        "repo": "flake-utils",
-        "type": "github"
-      }
-    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1717196966,
-        "narHash": "sha256-yZKhxVIKd2lsbOqYd5iDoUIwsRZFqE87smE2Vzf6Ck0=",
+        "lastModified": 1732014248,
+        "narHash": "sha256-y/MEyuJ5oBWrWAic/14LaIr/u5E0wRVzyYsouYY3W6w=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "57610d2f8f0937f39dbd72251e9614b1561942d8",
+        "rev": "23e89b7da85c3640bbc2173fe04f4bd114342367",
         "type": "github"
       },
       "original": {
@@ -36,44 +18,7 @@
     },
     "root": {
       "inputs": {
-        "nixpkgs": "nixpkgs",
-        "rust-overlay": "rust-overlay"
-      }
-    },
-    "rust-overlay": {
-      "inputs": {
-        "flake-utils": "flake-utils",
-        "nixpkgs": [
-          "nixpkgs"
-        ]
-      },
-      "locked": {
-        "lastModified": 1717442957,
-        "narHash": "sha256-w0fqHofxM2hf3pGDXCPSdH0A09v6FgHm6I38nCWA96k=",
-        "owner": "oxalica",
-        "repo": "rust-overlay",
-        "rev": "025e1742de4fa75b3fb63818bd9726d17da6a102",
-        "type": "github"
-      },
-      "original": {
-        "owner": "oxalica",
-        "repo": "rust-overlay",
-        "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"
+        "nixpkgs": "nixpkgs"
       }
     }
   },
diff --git a/flake.nix b/flake.nix
index 7704f25..a4378cb 100644
--- a/flake.nix
+++ b/flake.nix
@@ -1,20 +1,10 @@
 {
-  inputs = {
-    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
-    rust-overlay = {
-      url = "github:oxalica/rust-overlay";
-      inputs = {
-        nixpkgs.follows = "nixpkgs";
-      };
-    };
-  };
+  inputs.nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
 
   outputs =
     {
       self,
       nixpkgs,
-      rust-overlay,
-      ...
     }:
     let
       systems = [
@@ -23,58 +13,27 @@
         "x86_64-darwin"
         "x86_64-linux"
       ];
-      inherit (nixpkgs) lib;
-      forEachSystem =
-        f:
-        (lib.listToAttrs (
-          map (system: {
-            name = system;
-            value = f {
-              inherit system;
-              pkgs = import nixpkgs {
-                inherit system;
-                overlays = [ rust-overlay.overlays.default ];
-              };
-            };
-          }) systems
-        ));
+      forEachSystem = nixpkgs.lib.genAttrs systems;
+      pkgsFor = nixpkgs.legacyPackages;
     in
     {
-      devShells = forEachSystem (
-        { pkgs, system }:
-        {
-          default = pkgs.mkShell {
-            inputsFrom = [ self.packages.${system}.default ];
+      devShells = forEachSystem (system: {
+        default = pkgsFor.${system}.mkShell {
+          inputsFrom = [ self.packages.${system}.default ];
 
-            packages = [
-              (pkgs.rust-bin.stable.latest.default.override {
-                extensions = [
-                  "rustfmt"
-                  "rust-analyzer"
-                  "clippy"
-                ];
-              })
-            ];
-          };
-        }
-      );
+          packages = with pkgsFor.${system}; [
+            cargo
+            clippy
+            rust-analyzer
+            rustfmt
+          ];
+        };
+      });
 
-      packages = forEachSystem (
-        { pkgs, system }:
-        {
-          default = self.packages.${system}.whiskers;
-          whiskers = pkgs.callPackage ./default.nix {
-            rustPlatform =
-              let
-                toolchain = pkgs.rust-bin.stable.latest.default;
-              in
-              pkgs.makeRustPlatform {
-                cargo = toolchain;
-                rustc = toolchain;
-              };
-          };
-        }
-      );
+      packages = forEachSystem (system: {
+        default = self.packages.${system}.whiskers;
+        whiskers = pkgsFor.${system}.callPackage ./default.nix { };
+      });
 
       overlays.default = final: _: { catppuccin-whiskers = final.callPackage ./default.nix { }; };
     };
diff --git a/src/matrix.rs b/src/matrix.rs
index 01a0aa3..8c8c8b9 100644
--- a/src/matrix.rs
+++ b/src/matrix.rs
@@ -30,7 +30,7 @@ pub fn from_values(
             tera::Value::String(s) => {
                 let iterable = iterables
                     .get(s.as_str())
-                    .ok_or(Error::UnknownIterable { name: s.clone() })?;
+                    .ok_or_else(|| Error::UnknownIterable { name: s.clone() })?;
                 Ok((s, iterable.clone()))
             }
             tera::Value::Object(o) => {