NixOS · MattSturgeon · Jan 15, 2026 · Jan 15, 2026
diff --git a/nixos/lib/eval-config-minimal.nix b/nixos/lib/eval-config-minimal.nix
@@ -39,7 +39,7 @@ let
       inherit prefix modules;
       class = "nixos";
       specialArgs = {
-        modulesPath = builtins.toString ../modules;
+        modulesPath = toString ../modules;
       }
       // specialArgs;
     };

diff --git a/nixos/lib/make-btrfs-fs.nix b/nixos/lib/make-btrfs-fs.nix
@@ -65,7 +65,7 @@ pkgs.stdenv.mkDerivation {
       return 1
     fi
 
-    if [ ${builtins.toString compressImage} ]; then
+    if [ ${toString compressImage} ]; then
       echo "Compressing image"
       zstd -v --no-progress ./$img -o $out
     fi

diff --git a/nixos/lib/make-ext4-fs.nix b/nixos/lib/make-ext4-fs.nix
@@ -101,7 +101,7 @@ pkgs.stdenv.mkDerivation {
 
     resize2fs $img $new_size
 
-    if [ ${builtins.toString compressImage} ]; then
+    if [ ${toString compressImage} ]; then
       echo "Compressing image"
       zstd -T$NIX_BUILD_CORES -v --no-progress ./$img -o $out
     fi

diff --git a/nixos/lib/systemd-lib.nix b/nixos/lib/systemd-lib.nix
@@ -138,7 +138,7 @@ rec {
   toIntBaseDetected =
     value:
     assert (match "[0-9]+|0x[0-9a-fA-F]+" value) != null;
-    (builtins.fromTOML "v=${value}").v;
+    (fromTOML "v=${value}").v;
 
   hexChars = stringToCharacters "0123456789abcdefABCDEF";
 

diff --git a/nixos/lib/testing/driver.nix b/nixos/lib/testing/driver.nix
@@ -67,8 +67,8 @@ let
         ${lib.optionalString (!config.skipTypeCheck) ''
           # prepend type hints so the test script can be type checked with mypy
           cat "${../test-script-prepend.py}" >> testScriptWithTypes
-          echo "${builtins.toString machineNames}" >> testScriptWithTypes
-          echo "${builtins.toString vlanNames}" >> testScriptWithTypes
+          echo "${toString machineNames}" >> testScriptWithTypes
+          echo "${toString vlanNames}" >> testScriptWithTypes
           echo -n "$testScript" >> testScriptWithTypes
 
           echo "Running type check (enable/disable: config.skipTypeCheck)"

diff --git a/nixos/modules/config/fanout.nix b/nixos/modules/config/fanout.nix
@@ -8,7 +8,7 @@ let
   cfg = config.services.fanout;
   mknodCmds =
     n:
-    lib.lists.imap0 (i: s: "mknod /dev/fanout${builtins.toString i} c $MAJOR ${builtins.toString i}") (
+    lib.lists.imap0 (i: s: "mknod /dev/fanout${toString i} c $MAJOR ${toString i}") (
       lib.lists.replicate n ""
     );
 in
@@ -33,7 +33,7 @@ in
     boot.kernelModules = [ "fanout" ];
 
     boot.extraModprobeConfig = ''
-      options fanout buffersize=${builtins.toString cfg.bufferSize}
+      options fanout buffersize=${toString cfg.bufferSize}
     '';
 
     systemd.services.fanout = {

diff --git a/nixos/modules/config/i18n.nix b/nixos/modules/config/i18n.nix
@@ -16,7 +16,7 @@ let
     (lib.mapAttrs (n: v: (sanitizeUTF8Capitalization v)))
     (lib.mapAttrsToList (LCRole: lang: lang + "/" + (config.i18n.localeCharsets.${LCRole} or "UTF-8")))
   ]
-  ++ (builtins.map sanitizeUTF8Capitalization (
+  ++ (map sanitizeUTF8Capitalization (
     lib.optionals (builtins.isList config.i18n.extraLocales) config.i18n.extraLocales
   ))
   ++ (lib.optional (builtins.isString config.i18n.extraLocales) config.i18n.extraLocales);

diff --git a/nixos/modules/config/zram.nix b/nixos/modules/config/zram.nix
@@ -126,7 +126,7 @@ in
     services.zram-generator.enable = true;
 
     services.zram-generator.settings = lib.listToAttrs (
-      builtins.map (dev: {
+      map (dev: {
         name = dev;
         value =
           let

diff --git a/nixos/modules/hardware/ckb-next.nix b/nixos/modules/hardware/ckb-next.nix
@@ -37,7 +37,7 @@ in
       wantedBy = [ "multi-user.target" ];
       serviceConfig = {
         ExecStart = "${cfg.package}/bin/ckb-next-daemon ${
-          lib.optionalString (cfg.gid != null) "--gid=${builtins.toString cfg.gid}"
+          lib.optionalString (cfg.gid != null) "--gid=${toString cfg.gid}"
         }";
         Restart = "on-failure";
       };

diff --git a/nixos/modules/hardware/openrazer.nix b/nixos/modules/hardware/openrazer.nix
@@ -22,8 +22,8 @@ let
       sync_effects_enabled = ${toPyBoolStr cfg.syncEffectsEnabled}
       devices_off_on_screensaver = ${toPyBoolStr cfg.devicesOffOnScreensaver}
       battery_notifier = ${toPyBoolStr cfg.batteryNotifier.enable}
-      battery_notifier_freq = ${builtins.toString cfg.batteryNotifier.frequency}
-      battery_notifier_percent = ${builtins.toString cfg.batteryNotifier.percentage}
+      battery_notifier_freq = ${toString cfg.batteryNotifier.frequency}
+      battery_notifier_percent = ${toString cfg.batteryNotifier.percentage}
 
       [Statistics]
       key_statistics = ${toPyBoolStr cfg.keyStatistics}

diff --git a/nixos/modules/installer/cd-dvd/iso-image.nix b/nixos/modules/installer/cd-dvd/iso-image.nix
@@ -174,7 +174,7 @@ let
 
   baseIsolinuxCfg = ''
     SERIAL 0 115200
-    TIMEOUT ${builtins.toString syslinuxTimeout}
+    TIMEOUT ${toString syslinuxTimeout}
     UI vesamenu.c32
     MENU BACKGROUND /isolinux/background.png
 

diff --git a/nixos/modules/misc/mandoc.nix b/nixos/modules/misc/mandoc.nix
@@ -17,7 +17,7 @@ let
       if lib.isString value || lib.isPath value then
         "output ${name} ${value}"
       else if lib.isInt value then
-        "output ${name} ${builtins.toString value}"
+        "output ${name} ${toString value}"
       else if lib.isBool value then
         lib.optionalString value "output ${name}"
       else if value == null then

diff --git a/nixos/modules/misc/nixpkgs-flake.nix b/nixos/modules/misc/nixpkgs-flake.nix
@@ -21,7 +21,7 @@ in
       default = null;
       defaultText = "if (using nixpkgsFlake.lib.nixosSystem) then self.outPath else null";
 
-      example = ''builtins.fetchTarball { name = "source"; sha256 = "${lib.fakeHash}"; url = "https://github.com/nixos/nixpkgs/archive/somecommit.tar.gz"; }'';
+      example = ''fetchTarball { name = "source"; sha256 = "${lib.fakeHash}"; url = "https://github.com/nixos/nixpkgs/archive/somecommit.tar.gz"; }'';
 
       description = ''
         The path to the nixpkgs sources used to build the system. This is automatically set up to be
@@ -30,7 +30,7 @@ in
 
         This can also be optionally set if the NixOS system is not built with a flake but still uses
         pinned sources: set this to the store path for the nixpkgs sources used to build the system,
-        as may be obtained by `builtins.fetchTarball`, for example.
+        as may be obtained by `fetchTarball`, for example.
 
         Note: the name of the store path must be "source" due to
         <https://github.com/NixOS/nix/issues/7075>.

diff --git a/nixos/modules/programs/atop.nix b/nixos/modules/programs/atop.nix
@@ -107,7 +107,7 @@ in
       environment.etc = lib.mkIf (cfg.settings != { }) {
         atoprc.text = lib.concatStrings (
           lib.mapAttrsToList (n: v: ''
-            ${n} ${builtins.toString v}
+            ${n} ${toString v}
           '') cfg.settings
         );
       };

diff --git a/nixos/modules/programs/bash/undistract-me.nix b/nixos/modules/programs/bash/undistract-me.nix
@@ -27,7 +27,7 @@ in
 
   config = lib.mkIf cfg.enable {
     programs.bash.promptPluginInit = ''
-      export LONG_RUNNING_COMMAND_TIMEOUT=${builtins.toString cfg.timeout}
+      export LONG_RUNNING_COMMAND_TIMEOUT=${toString cfg.timeout}
       export UDM_PLAY_SOUND=${if cfg.playSound then "1" else "0"}
       . "${pkgs.undistract-me}/etc/profile.d/undistract-me.sh"
     '';

diff --git a/nixos/modules/programs/benchexec.nix b/nixos/modules/programs/benchexec.nix
@@ -71,7 +71,7 @@ in
     # See <https://github.com/sosy-lab/benchexec/blob/3.18/doc/INSTALL.md#setting-up-cgroups>.
     systemd.services = builtins.listToAttrs (
       map (user: {
-        name = "user@${builtins.toString (uid user)}";
+        name = "user@${toString (uid user)}";
         value = {
           serviceConfig.Delegate = "yes";
           overrideStrategy = "asDropin";

diff --git a/nixos/modules/programs/firefox.nix b/nixos/modules/programs/firefox.nix
@@ -305,7 +305,7 @@ in
           }) cfg.preferences
         );
         ExtensionSettings = builtins.listToAttrs (
-          builtins.map (
+          map (
             lang:
             lib.attrsets.nameValuePair "langpack-${lang}@firefox.mozilla.org" {
               installation_mode = "normal_installed";

diff --git a/nixos/modules/programs/firejail.nix b/nixos/modules/programs/firejail.nix
@@ -34,14 +34,13 @@ let
                     extraArgs = [ ];
                   };
               args = lib.escapeShellArgs (
-                opts.extraArgs
-                ++ (lib.optional (opts.profile != null) "--profile=${builtins.toString opts.profile}")
+                opts.extraArgs ++ (lib.optional (opts.profile != null) "--profile=${toString opts.profile}")
               );
             in
             ''
               cat <<_EOF >$out/bin/${command}
               #! ${pkgs.runtimeShell} -e
-              exec /run/wrappers/bin/firejail ${args} -- ${builtins.toString opts.executable} "\$@"
+              exec /run/wrappers/bin/firejail ${args} -- ${toString opts.executable} "\$@"
               _EOF
               chmod 0755 $out/bin/${command}
 

diff --git a/nixos/modules/programs/fish.nix b/nixos/modules/programs/fish.nix
@@ -295,7 +295,7 @@ in
           pkgs.buildEnv {
             name = "system_fish-completions";
             ignoreCollisions = true;
-            paths = builtins.map generateCompletions config.environment.systemPackages;
+            paths = map generateCompletions config.environment.systemPackages;
           };
       })
 

diff --git a/nixos/modules/programs/fuse.nix b/nixos/modules/programs/fuse.nix
@@ -58,7 +58,7 @@ in
 
     environment.etc."fuse.conf".text = ''
       ${lib.optionalString (!cfg.userAllowOther) "#"}user_allow_other
-      mount_max = ${builtins.toString cfg.mountMax}
+      mount_max = ${toString cfg.mountMax}
     '';
 
   };

diff --git a/nixos/modules/programs/gamescope.nix b/nixos/modules/programs/gamescope.nix
@@ -10,13 +10,13 @@ let
   gamescope =
     let
       wrapperArgs =
-        lib.optional (cfg.args != [ ]) ''--add-flags "${builtins.toString cfg.args}"''
+        lib.optional (cfg.args != [ ]) ''--add-flags "${toString cfg.args}"''
         ++ builtins.attrValues (builtins.mapAttrs (var: val: "--set-default ${var} ${val}") cfg.env);
     in
     pkgs.runCommand "gamescope" { nativeBuildInputs = [ pkgs.makeBinaryWrapper ]; } ''
       mkdir -p $out/bin
       makeWrapper ${cfg.package}/bin/gamescope $out/bin/gamescope --inherit-argv0 \
-        ${builtins.toString wrapperArgs}
+        ${toString wrapperArgs}
       ln -s ${cfg.package}/bin/gamescopectl $out/bin/gamescopectl
     '';
 in

diff --git a/nixos/modules/programs/htop.nix b/nixos/modules/programs/htop.nix
@@ -12,13 +12,13 @@ let
   fmt =
     value:
     if builtins.isList value then
-      builtins.concatStringsSep " " (builtins.map fmt value)
+      builtins.concatStringsSep " " (map fmt value)
     else if builtins.isString value then
       value
     else if builtins.isBool value then
       if value then "1" else "0"
     else if builtins.isInt value then
-      builtins.toString value
+      toString value
     else
       throw "Unrecognized type ${builtins.typeOf value} in htop settings";
 

diff --git a/nixos/modules/programs/less.nix b/nixos/modules/programs/less.nix
@@ -124,7 +124,7 @@ in
     environment.systemPackages = [ cfg.package ];
 
     environment.variables = {
-      LESSKEYIN_SYSTEM = builtins.toString lessKey;
+      LESSKEYIN_SYSTEM = toString lessKey;
     }
     // lib.optionalAttrs (cfg.lessopen != null) {
       LESSOPEN = cfg.lessopen;

diff --git a/nixos/modules/programs/liboping.nix b/nixos/modules/programs/liboping.nix
@@ -15,7 +15,7 @@ in
   config = lib.mkIf cfg.enable {
     environment.systemPackages = with pkgs; [ liboping ];
     security.wrappers = lib.mkMerge (
-      builtins.map
+      map
         (exec: {
           "${exec}" = {
             owner = "root";

diff --git a/nixos/modules/programs/light.nix b/nixos/modules/programs/light.nix
@@ -71,8 +71,8 @@ in
       bindings =
         let
           light = "${pkgs.light}/bin/light";
-          step = builtins.toString cfg.brightnessKeys.step;
-          minBrightness = builtins.toString cfg.brightnessKeys.minBrightness;
+          step = toString cfg.brightnessKeys.step;
+          minBrightness = toString cfg.brightnessKeys.minBrightness;
         in
         [
           {

diff --git a/nixos/modules/programs/neovim.nix b/nixos/modules/programs/neovim.nix
@@ -171,12 +171,12 @@ in
       builtins.attrValues (
         builtins.mapAttrs (name: value: {
           name = "xdg/nvim/${name}";
-          value = builtins.removeAttrs (
+          value = removeAttrs (
             value
             // {
               target = "xdg/nvim/${value.target}";
             }
-          ) (lib.optionals (builtins.isNull value.source) [ "source" ]);
+          ) (lib.optionals (isNull value.source) [ "source" ]);
         }) cfg.runtime
       )
     );

diff --git a/nixos/modules/programs/nncp.nix b/nixos/modules/programs/nncp.nix
@@ -81,7 +81,7 @@ in
       script = ''
         umask 127
         rm -f ${nncpCfgFile}
-        for f in ${jsonCfgFile} ${builtins.toString config.programs.nncp.secrets}
+        for f in ${jsonCfgFile} ${toString config.programs.nncp.secrets}
         do
           ${lib.getExe pkgs.hjson-go} -c <"$f"
         done |${lib.getExe pkgs.jq} --slurp 'reduce .[] as $x ({}; . * $x)' >${nncpCfgFile}

diff --git a/nixos/modules/programs/proxychains.nix b/nixos/modules/programs/proxychains.nix
@@ -10,18 +10,16 @@ let
 
   configFile = ''
     ${cfg.chain.type}_chain
-    ${lib.optionalString (
-      cfg.chain.type == "random"
-    ) "chain_len = ${builtins.toString cfg.chain.length}"}
+    ${lib.optionalString (cfg.chain.type == "random") "chain_len = ${toString cfg.chain.length}"}
     ${lib.optionalString cfg.proxyDNS "proxy_dns"}
     ${lib.optionalString cfg.quietMode "quiet_mode"}
-    remote_dns_subnet ${builtins.toString cfg.remoteDNSSubnet}
-    tcp_read_time_out ${builtins.toString cfg.tcpReadTimeOut}
-    tcp_connect_time_out ${builtins.toString cfg.tcpConnectTimeOut}
+    remote_dns_subnet ${toString cfg.remoteDNSSubnet}
+    tcp_read_time_out ${toString cfg.tcpReadTimeOut}
+    tcp_connect_time_out ${toString cfg.tcpConnectTimeOut}
     localnet ${cfg.localnet}
     [ProxyList]
     ${builtins.concatStringsSep "\n" (
-      lib.mapAttrsToList (k: v: "${v.type} ${v.host} ${builtins.toString v.port}") (
+      lib.mapAttrsToList (k: v: "${v.type} ${v.host} ${toString v.port}") (
         lib.filterAttrs (k: v: v.enable) cfg.proxies
       )
     )}

diff --git a/nixos/modules/programs/spacefm.nix b/nixos/modules/programs/spacefm.nix
@@ -54,7 +54,7 @@ in
     environment.systemPackages = [ pkgs.spaceFM ];
 
     environment.etc."spacefm/spacefm.conf".text = lib.concatStrings (
-      lib.mapAttrsToList (n: v: "${n}=${builtins.toString v}\n") cfg.settings
+      lib.mapAttrsToList (n: v: "${n}=${toString v}\n") cfg.settings
     );
   };
 }
diff --git a/nixos/modules/programs/ssh.nix b/nixos/modules/programs/ssh.nix
@@ -33,7 +33,7 @@ let
   knownHostsFiles = [
     "/etc/ssh/ssh_known_hosts"
   ]
-  ++ builtins.map pkgs.copyPathToStore cfg.knownHostsFiles;
+  ++ map pkgs.copyPathToStore cfg.knownHostsFiles;
 
 in
 {

diff --git a/nixos/modules/programs/steam.nix b/nixos/modules/programs/steam.nix
@@ -19,7 +19,7 @@ let
     in
     pkgs.writeShellScriptBin "steam-gamescope" ''
       ${builtins.concatStringsSep "\n" exports}
-      gamescope --steam ${builtins.toString cfg.gamescopeSession.args} -- steam ${builtins.toString cfg.gamescopeSession.steamArgs}
+      gamescope --steam ${toString cfg.gamescopeSession.args} -- steam ${toString cfg.gamescopeSession.steamArgs}
     '';
 
   gamescopeSessionFile =

diff --git a/nixos/modules/programs/tsm-client.nix b/nixos/modules/programs/tsm-client.nix
@@ -286,7 +286,7 @@ let
               ""
             # just output key if value is `true`
             else if isInt value then
-              "  ${builtins.toString value}"
+              "  ${toString value}"
             else if path.check value then
               "  \"${value}\""
             # enclose path in ".."

diff --git a/nixos/modules/programs/xfs_quota.nix b/nixos/modules/programs/xfs_quota.nix
@@ -85,13 +85,13 @@ in
 
     environment.etc.projects.source = pkgs.writeText "etc-project" (
       builtins.concatStringsSep "\n" (
-        lib.mapAttrsToList (name: opts: "${builtins.toString opts.id}:${opts.path}") cfg.projects
+        lib.mapAttrsToList (name: opts: "${toString opts.id}:${opts.path}") cfg.projects
       )
     );
 
     environment.etc.projid.source = pkgs.writeText "etc-projid" (
       builtins.concatStringsSep "\n" (
-        lib.mapAttrsToList (name: opts: "${name}:${builtins.toString opts.id}") cfg.projects
+        lib.mapAttrsToList (name: opts: "${name}:${toString opts.id}") cfg.projects
       )
     );
 

diff --git a/nixos/modules/programs/xss-lock.nix b/nixos/modules/programs/xss-lock.nix
@@ -41,7 +41,7 @@ in
           "${pkgs.xss-lock}/bin/xss-lock"
           "--session \${XDG_SESSION_ID}"
         ]
-        ++ (builtins.map lib.escapeShellArg cfg.extraOptions)
+        ++ (map lib.escapeShellArg cfg.extraOptions)
         ++ [
           "--"
           cfg.lockerCommand

diff --git a/nixos/modules/programs/yubikey-touch-detector.nix b/nixos/modules/programs/yubikey-touch-detector.nix
@@ -49,9 +49,9 @@ in
       path = [ pkgs.gnupg ];
 
       environment = {
-        YUBIKEY_TOUCH_DETECTOR_LIBNOTIFY = builtins.toString cfg.libnotify;
-        YUBIKEY_TOUCH_DETECTOR_NOSOCKET = builtins.toString (!cfg.unixSocket);
-        YUBIKEY_TOUCH_DETECTOR_VERBOSE = builtins.toString cfg.verbose;
+        YUBIKEY_TOUCH_DETECTOR_LIBNOTIFY = toString cfg.libnotify;
+        YUBIKEY_TOUCH_DETECTOR_NOSOCKET = toString (!cfg.unixSocket);
+        YUBIKEY_TOUCH_DETECTOR_VERBOSE = toString cfg.verbose;
       };
 
       wantedBy = [ "graphical-session.target" ];