diff --git a/doc/release-notes/rl-2605.section.md b/doc/release-notes/rl-2605.section.md
index 56a6c2504141..6ed35140cb2a 100644
--- a/doc/release-notes/rl-2605.section.md
+++ b/doc/release-notes/rl-2605.section.md
@@ -410,6 +410,8 @@ gnuradioMinimal.override {
 
 - `fetchFromSavannah` is now deprecated and is expected to be fully removed in a future release. From now on, use `fetchgit` or a Savannah releases mirror when applicable.
 
+- Using nested lists in build/runtime inputs in `mkDerivation` is now deprecated.
+
 ### Additions and Improvements {#sec-nixpkgs-release-26.05-lib-additions-improvements}
 
 - The builder `php.buildComposerProject2` for PHP applications has been improved for better reliability and stability.
diff --git a/pkgs/applications/misc/makehuman/default.nix b/pkgs/applications/misc/makehuman/default.nix
index 51f27c3d7c10..309d0a84771a 100644
--- a/pkgs/applications/misc/makehuman/default.nix
+++ b/pkgs/applications/misc/makehuman/default.nix
@@ -55,9 +55,7 @@ stdenv.mkDerivation rec {
     qtbase
   ];
 
-  propagatedBuildInputs = [
-    pydeps
-  ];
+  propagatedBuildInputs = pydeps;
 
   finalSource = "${pname}-final";
 
diff --git a/pkgs/applications/networking/instant-messengers/gajim/default.nix b/pkgs/applications/networking/instant-messengers/gajim/default.nix
index 1a2a01727179..6026917dedbe 100644
--- a/pkgs/applications/networking/instant-messengers/gajim/default.nix
+++ b/pkgs/applications/networking/instant-messengers/gajim/default.nix
@@ -113,10 +113,10 @@ python3.pkgs.buildPythonApplication rec {
       sqlalchemy
       emoji
       httpx
-      httpx.optional-dependencies.socks
       h2
       truststore
     ]
+    ++ httpx.optional-dependencies.socks
     ++ lib.optionals enableE2E [
       pycrypto
       python-gnupg
diff --git a/pkgs/by-name/_1/_1password-cli/package.nix b/pkgs/by-name/_1/_1password-cli/package.nix
index c8f0e8f9552b..2ab9a7ad7180 100644
--- a/pkgs/by-name/_1/_1password-cli/package.nix
+++ b/pkgs/by-name/_1/_1password-cli/package.nix
@@ -51,7 +51,7 @@ stdenv.mkDerivation {
     versionCheckHook
   ]
   ++ lib.optional stdenv.hostPlatform.isLinux autoPatchelfHook
-  ++ lib.optional stdenv.hostPlatform.isDarwin [
+  ++ lib.optionals stdenv.hostPlatform.isDarwin [
     xar
     cpio
   ];
diff --git a/pkgs/by-name/aw/aws-sam-cli/package.nix b/pkgs/by-name/aw/aws-sam-cli/package.nix
index e3acde7e1a3d..01a20b3b9ccb 100644
--- a/pkgs/by-name/aw/aws-sam-cli/package.nix
+++ b/pkgs/by-name/aw/aws-sam-cli/package.nix
@@ -67,22 +67,25 @@ python3.pkgs.buildPythonApplication rec {
       tzlocal
       watchdog
     ]
-    ++ (with python3.pkgs.boto3-stubs.optional-dependencies; [
-      apigateway
-      cloudformation
-      ecr
-      iam
-      kinesis
-      lambda
-      s3
-      schemas
-      secretsmanager
-      signer
-      sqs
-      stepfunctions
-      sts
-      xray
-    ]);
+    ++ (
+      with python3.pkgs.boto3-stubs.optional-dependencies;
+      lib.concatLists [
+        apigateway
+        cloudformation
+        ecr
+        iam
+        kinesis
+        lambda
+        s3
+        schemas
+        secretsmanager
+        signer
+        sqs
+        stepfunctions
+        sts
+        xray
+      ]
+    );
 
   patches = [
     # Remove after aws-sam-cli > 1.154.0
diff --git a/pkgs/by-name/ba/basedpyright/package.nix b/pkgs/by-name/ba/basedpyright/package.nix
index 3070840aac38..49fdb388ae4f 100644
--- a/pkgs/by-name/ba/basedpyright/package.nix
+++ b/pkgs/by-name/ba/basedpyright/package.nix
@@ -40,7 +40,7 @@ buildNpmPackage rec {
     docify
     pkg-config
   ]
-  ++ lib.optional stdenv.hostPlatform.isDarwin [ clang_20 ]; # clang_21 breaks keytar
+  ++ lib.optional stdenv.hostPlatform.isDarwin clang_20; # clang_21 breaks keytar
 
   buildInputs = [ libsecret ];
 
diff --git a/pkgs/by-name/br/browsr/package.nix b/pkgs/by-name/br/browsr/package.nix
index db45c39c6d68..a3b2fa3ca73e 100644
--- a/pkgs/by-name/br/browsr/package.nix
+++ b/pkgs/by-name/br/browsr/package.nix
@@ -46,7 +46,7 @@ python3Packages.buildPythonApplication (finalAttrs: {
       textual
       textual-universal-directorytree
     ]
-    ++ lib.attrVals extras finalAttrs.passthru.optional-dependencies;
+    ++ lib.flatten (lib.attrVals extras finalAttrs.passthru.optional-dependencies);
 
   optional-dependencies = with python3Packages; {
     all = [
diff --git a/pkgs/by-name/ca/caja-with-extensions/package.nix b/pkgs/by-name/ca/caja-with-extensions/package.nix
index 43034921a6de..d9374778cb86 100644
--- a/pkgs/by-name/ca/caja-with-extensions/package.nix
+++ b/pkgs/by-name/ca/caja-with-extensions/package.nix
@@ -26,7 +26,7 @@ stdenv.mkDerivation {
   ];
 
   buildInputs =
-    lib.forEach selectedExtensions (x: x.buildInputs)
+    lib.concatMap (x: x.buildInputs) selectedExtensions
     ++ selectedExtensions
     ++ [ caja ]
     ++ caja.buildInputs;
diff --git a/pkgs/by-name/cd/cdxgen/package.nix b/pkgs/by-name/cd/cdxgen/package.nix
index 24a15b7a8cb4..2f5f1e410631 100644
--- a/pkgs/by-name/cd/cdxgen/package.nix
+++ b/pkgs/by-name/cd/cdxgen/package.nix
@@ -30,9 +30,7 @@ stdenv.mkDerivation (finalAttrs: {
     pnpm_10
     python3 # required for sqlite3 bindings
   ]
-  ++ lib.optional stdenv.hostPlatform.isDarwin [
-    cctools.libtool
-  ];
+  ++ lib.optional stdenv.hostPlatform.isDarwin cctools.libtool;
 
   pnpmDeps = fetchPnpmDeps {
     inherit (finalAttrs) pname version src;
diff --git a/pkgs/by-name/et/etesync-dav/package.nix b/pkgs/by-name/et/etesync-dav/package.nix
index 046b650bbce4..8d02f6f709b4 100644
--- a/pkgs/by-name/et/etesync-dav/package.nix
+++ b/pkgs/by-name/et/etesync-dav/package.nix
@@ -27,17 +27,19 @@ python3Packages.buildPythonApplication (finalAttrs: {
 
   pythonRelaxDeps = [ "radicale" ];
 
-  dependencies = with python3Packages; [
-    appdirs
-    etebase
-    etesync
-    flask
-    flask-wtf
-    msgpack
-    (python3Packages.toPythonModule (radicale.override { python3 = python; }))
-    requests
-    requests.optional-dependencies.socks
-  ];
+  dependencies =
+    with python3Packages;
+    [
+      appdirs
+      etebase
+      etesync
+      flask
+      flask-wtf
+      msgpack
+      (python3Packages.toPythonModule (radicale.override { python3 = python; }))
+      requests
+    ]
+    ++ requests.optional-dependencies.socks;
 
   doCheck = false;
 
diff --git a/pkgs/by-name/fa/fastnlo-toolkit/package.nix b/pkgs/by-name/fa/fastnlo-toolkit/package.nix
index d717e9208d54..926e0a89db62 100644
--- a/pkgs/by-name/fa/fastnlo-toolkit/package.nix
+++ b/pkgs/by-name/fa/fastnlo-toolkit/package.nix
@@ -48,13 +48,11 @@ stdenv.mkDerivation (finalAttrs: {
   ++ lib.optional withPython python
   ++ lib.optional (withPython && python.isPy3k) ncurses;
 
-  propagatedNativeBuildInputs = lib.optional withPython [ swig ];
+  propagatedNativeBuildInputs = lib.optional withPython swig;
   propagatedBuildInputs = [
     zlib
   ]
-  ++ lib.optional withPython [
-    python.pkgs.distutils
-  ];
+  ++ lib.optional withPython python.pkgs.distutils;
 
   preConfigure = ''
     substituteInPlace ./fastnlotoolkit/Makefile.in \
diff --git a/pkgs/by-name/gn/gnome-panel/wrapper.nix b/pkgs/by-name/gn/gnome-panel/wrapper.nix
index cb7f6d5d160d..ec517b53f81f 100644
--- a/pkgs/by-name/gn/gnome-panel/wrapper.nix
+++ b/pkgs/by-name/gn/gnome-panel/wrapper.nix
@@ -34,7 +34,7 @@ stdenv.mkDerivation {
   ];
 
   buildInputs =
-    selectedPanelModulePackages ++ lib.forEach selectedPanelModulePackages (x: x.buildInputs or [ ]);
+    selectedPanelModulePackages ++ lib.concatMap (x: x.buildInputs or [ ]) selectedPanelModulePackages;
 
   dontUnpack = true;
   dontConfigure = true;
diff --git a/pkgs/by-name/gr/grap/package.nix b/pkgs/by-name/gr/grap/package.nix
index 3115c362ac7f..d131123dad15 100644
--- a/pkgs/by-name/gr/grap/package.nix
+++ b/pkgs/by-name/gr/grap/package.nix
@@ -38,9 +38,9 @@ python3Packages.buildPythonApplication rec {
   ];
 
   buildInputs = [
-    boost183.all
     libseccomp
-  ];
+  ]
+  ++ boost183.all;
 
   strictDeps = true;
 
diff --git a/pkgs/by-name/gr/groonga/package.nix b/pkgs/by-name/gr/groonga/package.nix
index c6d882d4feee..2c995d07f11f 100644
--- a/pkgs/by-name/gr/groonga/package.nix
+++ b/pkgs/by-name/gr/groonga/package.nix
@@ -51,7 +51,7 @@ stdenv.mkDerivation (finalAttrs: {
   ++ lib.optionals lz4Support [
     lz4
   ]
-  ++ lib.optional zlibSupport [
+  ++ lib.optionals zlibSupport [
     zlib
   ]
   ++ lib.optionals suggestSupport [
diff --git a/pkgs/by-name/is/isrcsubmit/package.nix b/pkgs/by-name/is/isrcsubmit/package.nix
index d157d9aafc7c..873d97f391ff 100644
--- a/pkgs/by-name/is/isrcsubmit/package.nix
+++ b/pkgs/by-name/is/isrcsubmit/package.nix
@@ -35,9 +35,7 @@ python3Packages.buildPythonApplication {
       musicbrainzngs
       discid
     ]
-    ++ lib.optional withKeyring [
-      keyring
-    ];
+    ++ lib.optional withKeyring keyring;
 
   pythonImportsCheck = [ "isrcsubmit" ];
 
diff --git a/pkgs/by-name/ji/jinja2-cli/package.nix b/pkgs/by-name/ji/jinja2-cli/package.nix
index a5ed8fcf1b77..04995502c270 100644
--- a/pkgs/by-name/ji/jinja2-cli/package.nix
+++ b/pkgs/by-name/ji/jinja2-cli/package.nix
@@ -37,7 +37,7 @@ python3.pkgs.buildPythonApplication rec {
     [
       jinja2
     ]
-    ++ lib.attrVals extras optional-dependencies;
+    ++ lib.flatten (lib.attrVals extras optional-dependencies);
 
   pythonImportsCheck = [ "jinja2cli" ];
 
diff --git a/pkgs/by-name/ki/kitsas/package.nix b/pkgs/by-name/ki/kitsas/package.nix
index bd7436c32c5c..d96b64028c4d 100644
--- a/pkgs/by-name/ki/kitsas/package.nix
+++ b/pkgs/by-name/ki/kitsas/package.nix
@@ -32,9 +32,7 @@ stdenv.mkDerivation (finalAttrs: {
     qt6.qtsvg
     qt6.qtwebengine
   ]
-  ++ lib.optional stdenv.hostPlatform.isLinux [
-    qt6.qtwayland
-  ];
+  ++ lib.optional stdenv.hostPlatform.isLinux qt6.qtwayland;
 
   # We use a separate build-dir as otherwise ld seems to get confused between
   # directory and executable name on buildPhase.
diff --git a/pkgs/by-name/la/ladybird/package.nix b/pkgs/by-name/la/ladybird/package.nix
index e62fd0f91a55..8c74b38a637f 100644
--- a/pkgs/by-name/la/ladybird/package.nix
+++ b/pkgs/by-name/la/ladybird/package.nix
@@ -131,7 +131,7 @@ stdenv.mkDerivation (finalAttrs: {
     icu78
     simdjson
   ]
-  ++ lib.optional stdenv.hostPlatform.isLinux [
+  ++ lib.optionals stdenv.hostPlatform.isLinux [
     libpulseaudio.dev
     qt6Packages.qtwayland
   ];
diff --git a/pkgs/by-name/li/libass/package.nix b/pkgs/by-name/li/libass/package.nix
index d3dc3d6053dc..61b8611327f0 100644
--- a/pkgs/by-name/li/libass/package.nix
+++ b/pkgs/by-name/li/libass/package.nix
@@ -45,9 +45,8 @@ stdenv.mkDerivation (finalAttrs: {
     harfbuzz
   ]
   ++ lib.optional fontconfigSupport fontconfig
-  ++ lib.optional stdenv.hostPlatform.isDarwin [
-    libiconv
-  ];
+  # TODO: remove dep after branchoff (in darwin stdenv)
+  ++ lib.optional stdenv.hostPlatform.isDarwin libiconv.out;
 
   meta = {
     description = "Portable ASS/SSA subtitle renderer";
diff --git a/pkgs/by-name/mc/mcrl2/package.nix b/pkgs/by-name/mc/mcrl2/package.nix
index eda177c67e3d..b849cbe89097 100644
--- a/pkgs/by-name/mc/mcrl2/package.nix
+++ b/pkgs/by-name/mc/mcrl2/package.nix
@@ -56,7 +56,7 @@ stdenv.mkDerivation rec {
     qt6.qtbase
     boost
   ]
-  ++ lib.optional stdenv.hostPlatform.isDarwin [ makeWrapper ];
+  ++ lib.optional stdenv.hostPlatform.isDarwin makeWrapper;
 
   dontWrapQtApps = true;
 
diff --git a/pkgs/by-name/mo/modrinth-app-unwrapped/package.nix b/pkgs/by-name/mo/modrinth-app-unwrapped/package.nix
index d48f3b3b436d..99a6e03c8abe 100644
--- a/pkgs/by-name/mo/modrinth-app-unwrapped/package.nix
+++ b/pkgs/by-name/mo/modrinth-app-unwrapped/package.nix
@@ -91,7 +91,7 @@ rustPlatform.buildRustPackage (finalAttrs: {
     pnpmConfigHook
     pnpm_10
   ]
-  ++ lib.optional stdenv.hostPlatform.isDarwin [
+  ++ lib.optionals stdenv.hostPlatform.isDarwin [
     makeBinaryWrapper
     xcbuild
   ];
diff --git a/pkgs/by-name/mu/music-assistant/package.nix b/pkgs/by-name/mu/music-assistant/package.nix
index 23610a242dd2..64b316f8d7c8 100644
--- a/pkgs/by-name/mu/music-assistant/package.nix
+++ b/pkgs/by-name/mu/music-assistant/package.nix
@@ -177,7 +177,7 @@ python.pkgs.buildPythonApplication rec {
       pytestCheckHook
     ]
     ++ lib.concatAttrValues optional-dependencies
-    ++ (map (provider: providerPackages.${provider} python.pkgs) [
+    ++ (lib.concatMap (provider: providerPackages.${provider} python.pkgs) [
       "audible"
       "dlna"
       "jellyfin"
diff --git a/pkgs/by-name/n8/n8n/package.nix b/pkgs/by-name/n8/n8n/package.nix
index 6a57b725baef..84491ae199d9 100644
--- a/pkgs/by-name/n8/n8n/package.nix
+++ b/pkgs/by-name/n8/n8n/package.nix
@@ -50,7 +50,7 @@ stdenv.mkDerivation (finalAttrs: {
     makeWrapper
     dart-sass
   ]
-  ++ lib.optional stdenv.hostPlatform.isDarwin [
+  ++ lib.optionals stdenv.hostPlatform.isDarwin [
     cctools
     xcbuild
   ];
diff --git a/pkgs/by-name/ni/nix-unit/package.nix b/pkgs/by-name/ni/nix-unit/package.nix
index 5d6e811ac2a1..0007f3ff469e 100644
--- a/pkgs/by-name/ni/nix-unit/package.nix
+++ b/pkgs/by-name/ni/nix-unit/package.nix
@@ -48,7 +48,7 @@ stdenv.mkDerivation (finalAttrs: {
     # nlohmann_json can be only discovered via cmake files
     cmake
   ]
-  ++ lib.optional stdenv.cc.isClang [ clang-tools ];
+  ++ lib.optional stdenv.cc.isClang clang-tools;
 
   postInstall = ''
     wrapProgram "$out/bin/nix-unit" --prefix PATH : ${difftastic}/bin
diff --git a/pkgs/by-name/no/novops/package.nix b/pkgs/by-name/no/novops/package.nix
index 582b31f11fbc..670d7a992255 100644
--- a/pkgs/by-name/no/novops/package.nix
+++ b/pkgs/by-name/no/novops/package.nix
@@ -25,7 +25,7 @@ rustPlatform.buildRustPackage (finalAttrs: {
   buildInputs = [
     openssl # required for openssl-sys
   ]
-  ++ lib.optional stdenv.hostPlatform.isDarwin [
+  ++ lib.optionals stdenv.hostPlatform.isDarwin [
     libiconv
   ];
 
diff --git a/pkgs/by-name/ol/ollama/package.nix b/pkgs/by-name/ol/ollama/package.nix
index 155c3ee506e9..2093557b0949 100644
--- a/pkgs/by-name/ol/ollama/package.nix
+++ b/pkgs/by-name/ol/ollama/package.nix
@@ -168,10 +168,12 @@ goBuild (finalAttrs: {
     cmake
     gitMinimal
   ]
-  ++ lib.optionals enableRocm [
-    rocmPackages.llvm.bintools
+  ++ lib.optionals enableRocm (
     rocmLibs
-  ]
+    ++ [
+      rocmPackages.llvm.bintools
+    ]
+  )
   ++ lib.optionals enableCuda [ cudaPackages.cuda_nvcc ]
   ++ lib.optionals (enableRocm || enableCuda) [
     makeBinaryWrapper
diff --git a/pkgs/by-name/pa/pat/package.nix b/pkgs/by-name/pa/pat/package.nix
index f52534b444fe..465ab4575510 100644
--- a/pkgs/by-name/pa/pat/package.nix
+++ b/pkgs/by-name/pa/pat/package.nix
@@ -27,7 +27,7 @@ buildGoModule (finalAttrs: {
 
   nativeBuildInputs = [ installShellFiles ];
 
-  buildInputs = lib.optional stdenv.hostPlatform.isLinux [ libax25 ];
+  buildInputs = lib.optional stdenv.hostPlatform.isLinux libax25;
 
   # Needed by wl2k-go go module for libax25 to include support for Linux' AX.25 stack by linking against libax25.
   # ref: https://github.com/la5nta/wl2k-go/blob/abe3ae5bf6a2eec670a21672d461d1c3e1d4c2f3/transport/ax25/ax25.go#L11-L17
diff --git a/pkgs/by-name/pa/patroni/package.nix b/pkgs/by-name/pa/patroni/package.nix
index 1a71561808c3..c2f035bd9674 100644
--- a/pkgs/by-name/pa/patroni/package.nix
+++ b/pkgs/by-name/pa/patroni/package.nix
@@ -50,7 +50,7 @@ python3Packages.buildPythonApplication (finalAttrs: {
       urllib3
       ydiff
     ])
-    ++ lib.attrVals extras finalAttrs.passthru.optional-dependencies;
+    ++ lib.flatten (lib.attrVals extras finalAttrs.passthru.optional-dependencies);
 
   optional-dependencies = with python3Packages; {
     aws = [ boto3 ];
diff --git a/pkgs/by-name/pe/persepolis/package.nix b/pkgs/by-name/pe/persepolis/package.nix
index d6fa0eaa6736..f07b52fad3dd 100644
--- a/pkgs/by-name/pe/persepolis/package.nix
+++ b/pkgs/by-name/pe/persepolis/package.nix
@@ -40,8 +40,9 @@ python3.pkgs.buildPythonApplication (finalAttrs: {
     "\${qtWrapperArgs[@]}"
   ];
 
-  propagatedBuildInputs = [
-    (with python3.pkgs; [
+  propagatedBuildInputs = (
+    with python3.pkgs;
+    [
       psutil
       pyside6
       pysocks
@@ -51,8 +52,8 @@ python3.pkgs.buildPythonApplication (finalAttrs: {
       setproctitle
       setuptools
       yt-dlp
-    ])
-  ];
+    ]
+  );
 
   meta = {
     description = "Download manager GUI written in Python";
diff --git a/pkgs/by-name/pv/pvzge/package.nix b/pkgs/by-name/pv/pvzge/package.nix
index 61bdf577cdcb..df5a2c35353e 100644
--- a/pkgs/by-name/pv/pvzge/package.nix
+++ b/pkgs/by-name/pv/pvzge/package.nix
@@ -34,7 +34,7 @@ stdenvNoCC.mkDerivation (finalAttrs: {
     makeWrapper
     imagemagick
   ]
-  ++ lib.optional stdenvNoCC.hostPlatform.isDarwin [ desktopToDarwinBundle ];
+  ++ lib.optional stdenvNoCC.hostPlatform.isDarwin desktopToDarwinBundle;
 
   postPatch = ''
     sed -i "s|<title>.*</title>|<title>PvZ2: Gardendless</title>|" docs/index.html
diff --git a/pkgs/by-name/py/pympress/package.nix b/pkgs/by-name/py/pympress/package.nix
index e5482da2bbe0..288ea438fb5d 100644
--- a/pkgs/by-name/py/pympress/package.nix
+++ b/pkgs/by-name/py/pympress/package.nix
@@ -37,9 +37,7 @@ python3Packages.buildPythonApplication (finalAttrs: {
       pycairo
       pygobject3
     ]
-    ++ lib.optional withVLC [
-      python-vlc
-    ];
+    ++ lib.optional withVLC python-vlc;
 
   nativeBuildInputs = [
     wrapGAppsHook3
diff --git a/pkgs/by-name/re/redo-apenwarr/package.nix b/pkgs/by-name/re/redo-apenwarr/package.nix
index adbb56107b22..38aae496b40d 100644
--- a/pkgs/by-name/re/redo-apenwarr/package.nix
+++ b/pkgs/by-name/re/redo-apenwarr/package.nix
@@ -66,11 +66,9 @@ stdenv.mkDerivation (finalAttrs: {
 
   nativeBuildInputs = [
     python3
-    (with python3.pkgs; [
-      beautifulsoup4
-      markdown
-    ])
     which
+    python3.pkgs.beautifulsoup4
+    python3.pkgs.markdown
     installShellFiles
     gnumake42 # fails with make 4.4
   ];
diff --git a/pkgs/by-name/re/renovate/package.nix b/pkgs/by-name/re/renovate/package.nix
index 44b29adaa74e..8c2dd9008831 100644
--- a/pkgs/by-name/re/renovate/package.nix
+++ b/pkgs/by-name/re/renovate/package.nix
@@ -42,7 +42,7 @@ stdenv.mkDerivation (finalAttrs: {
     python3
     yq-go
   ]
-  ++ lib.optional stdenv.hostPlatform.isDarwin [
+  ++ lib.optionals stdenv.hostPlatform.isDarwin [
     xcbuild
     cctools # contains libtool, required by better-sqlite3
   ];
diff --git a/pkgs/by-name/ry/ryubing/package.nix b/pkgs/by-name/ry/ryubing/package.nix
index 11c1b657625d..4551d4c6ffcc 100644
--- a/pkgs/by-name/ry/ryubing/package.nix
+++ b/pkgs/by-name/ry/ryubing/package.nix
@@ -43,10 +43,8 @@ buildDotnetModule rec {
   };
 
   nativeBuildInputs =
-    lib.optional stdenv.hostPlatform.isLinux [
-      wrapGAppsHook3
-    ]
-    ++ lib.optional stdenv.hostPlatform.isDarwin [
+    lib.optional stdenv.hostPlatform.isLinux wrapGAppsHook3
+    ++ lib.optionals stdenv.hostPlatform.isDarwin [
       cctools
       darwin.sigtool
     ];
@@ -82,11 +80,11 @@ buildDotnetModule rec {
     libGL
     SDL2
   ]
-  ++ lib.optional (!stdenv.hostPlatform.isDarwin) [
+  ++ lib.optionals (!stdenv.hostPlatform.isDarwin) [
     udev
     pulseaudio
   ]
-  ++ lib.optional stdenv.hostPlatform.isDarwin [ moltenvk ];
+  ++ lib.optional stdenv.hostPlatform.isDarwin moltenvk;
 
   projectFile = "Ryujinx.sln";
   testProjectFile = "src/Ryujinx.Tests/Ryujinx.Tests.csproj";
diff --git a/pkgs/by-name/sh/shairport-sync/package.nix b/pkgs/by-name/sh/shairport-sync/package.nix
index d760a0208aec..4fffcd8bbde7 100644
--- a/pkgs/by-name/sh/shairport-sync/package.nix
+++ b/pkgs/by-name/sh/shairport-sync/package.nix
@@ -75,7 +75,7 @@ stdenv.mkDerivation (finalAttrs: {
     # mkDerivation's splicing logic from kicking in.
     "${glib.dev}"
   ]
-  ++ optional enableAirplay2 [
+  ++ optionals enableAirplay2 [
     libplist.bin
     unixtools.xxd
   ];
diff --git a/pkgs/by-name/so/sope/package.nix b/pkgs/by-name/so/sope/package.nix
index 3ef83e1fe6ab..1178a10b7563 100644
--- a/pkgs/by-name/so/sope/package.nix
+++ b/pkgs/by-name/so/sope/package.nix
@@ -23,7 +23,7 @@ clangStdenv.mkDerivation rec {
     hash = "sha256-0G28qDXygDe/TJ2znNE+NVQry3bkqUO59jqtJm/t2S4=";
   };
 
-  nativeBuildInputs = lib.optional (libpq != null) [ libpq.pg_config ];
+  nativeBuildInputs = lib.optional (libpq != null) libpq.pg_config;
   buildInputs = [
     gnustep-base
     libxml2
diff --git a/pkgs/by-name/st/streamlink/package.nix b/pkgs/by-name/st/streamlink/package.nix
index 6dd2a98702b0..70ca89507d66 100644
--- a/pkgs/by-name/st/streamlink/package.nix
+++ b/pkgs/by-name/st/streamlink/package.nix
@@ -58,7 +58,7 @@ python3Packages.buildPythonApplication rec {
       urllib3
       websocket-client
     ]
-    ++ lib.attrVals extras optional-dependencies;
+    ++ lib.flatten (lib.attrVals extras optional-dependencies);
 
   optional-dependencies = with python3Packages; {
     decompress = urllib3.optional-dependencies.brotli ++ urllib3.optional-dependencies.zstd;
diff --git a/pkgs/by-name/te/terminusdb/package.nix b/pkgs/by-name/te/terminusdb/package.nix
index 535b866c13fb..4884cfc2208d 100644
--- a/pkgs/by-name/te/terminusdb/package.nix
+++ b/pkgs/by-name/te/terminusdb/package.nix
@@ -105,10 +105,8 @@ stdenv.mkDerivation (finalAttrs: {
   strictDeps = true;
 
   nativeBuildInputs = [
-    (with rustPlatform; [
-      cargoSetupHook
-      bindgenHook # provides libclang
-    ])
+    rustPlatform.cargoSetupHook
+    rustPlatform.bindgenHook # provides libclang
     cargo
     installShellFiles
     protobuf
diff --git a/pkgs/by-name/ti/tigervnc/package.nix b/pkgs/by-name/ti/tigervnc/package.nix
index 4e6a935afb58..cebd3311ac44 100644
--- a/pkgs/by-name/ti/tigervnc/package.nix
+++ b/pkgs/by-name/ti/tigervnc/package.nix
@@ -209,7 +209,7 @@ stdenv.mkDerivation (finalAttrs: {
     ]
   );
 
-  propagatedBuildInputs = lib.optional stdenv.hostPlatform.isLinux xorg-server.propagatedBuildInputs;
+  propagatedBuildInputs = lib.optionals stdenv.hostPlatform.isLinux xorg-server.propagatedBuildInputs;
 
   passthru.tests.tigervnc = nixosTests.tigervnc;
 
diff --git a/pkgs/by-name/tu/turses/package.nix b/pkgs/by-name/tu/turses/package.nix
index a24ee8d7dcb5..7c04dae2c0c2 100644
--- a/pkgs/by-name/tu/turses/package.nix
+++ b/pkgs/by-name/tu/turses/package.nix
@@ -22,10 +22,12 @@ let
           tag = "v${version}";
           hash = "sha256-3BbQeCaAhlz9h5GnhficNubJHu4kTpnCDM4oKzlti0w=";
         };
-        dependencies = oldAttrs.dependencies ++ [
-          super.six
-          super.requests.optional-dependencies.socks
-        ];
+        dependencies =
+          oldAttrs.dependencies
+          ++ [
+            super.six
+          ]
+          ++ super.requests.optional-dependencies.socks;
         doCheck = false;
       });
     };
diff --git a/pkgs/by-name/vc/vcv-rack/package.nix b/pkgs/by-name/vc/vcv-rack/package.nix
index 8e49779c72c1..d7dcbe4c22ca 100644
--- a/pkgs/by-name/vc/vcv-rack/package.nix
+++ b/pkgs/by-name/vc/vcv-rack/package.nix
@@ -123,7 +123,7 @@ let
       libjack2
       libpulseaudio
     ]
-    ++ lib.optional stdenv.hostPlatform.isDarwin [ apple-sdk_14 ];
+    ++ lib.optional stdenv.hostPlatform.isDarwin apple-sdk_14;
 
     cmakeFlags = [
       (lib.cmakeBool "RTAUDIO_API_ALSA" stdenv.hostPlatform.isLinux)
diff --git a/pkgs/by-name/vo/voxtype/package.nix b/pkgs/by-name/vo/voxtype/package.nix
index 62084d779d78..b28df4f4a5ac 100644
--- a/pkgs/by-name/vo/voxtype/package.nix
+++ b/pkgs/by-name/vo/voxtype/package.nix
@@ -82,7 +82,7 @@ rustPlatform.buildRustPackage (finalAttrs: {
     makeBinaryWrapper
     pkg-config
   ]
-  ++ lib.optional vulkanSupport [
+  ++ lib.optionals vulkanSupport [
     shaderc
     vulkan-headers
     vulkan-loader
diff --git a/pkgs/by-name/wh/whoogle-search/package.nix b/pkgs/by-name/wh/whoogle-search/package.nix
index def30f89e255..260ee63aa50e 100644
--- a/pkgs/by-name/wh/whoogle-search/package.nix
+++ b/pkgs/by-name/wh/whoogle-search/package.nix
@@ -18,44 +18,46 @@ python3Packages.buildPythonApplication (finalAttrs: {
 
   build-system = with python3Packages; [ setuptools ];
 
-  dependencies = with python3Packages; [
-    attrs
-    beautifulsoup4
-    brotli
-    cachetools
-    certifi
-    cffi
-    click
-    cryptography
-    cssutils
-    defusedxml
-    flask
-    h11
-    httpcore
-    httpx
-    httpx.optional-dependencies.http2
-    httpx.optional-dependencies.socks
-    idna
-    itsdangerous
-    jinja2
-    markupsafe
-    more-itertools
-    packaging
-    pluggy
-    pycodestyle
-    pycparser
-    pyopenssl
-    pyparsing
-    pytest
-    python-dateutil
-    python-dotenv
-    soupsieve
-    stem
-    validators
-    waitress
-    wcwidth
-    werkzeug
-  ];
+  dependencies =
+    with python3Packages;
+    [
+      attrs
+      beautifulsoup4
+      brotli
+      cachetools
+      certifi
+      cffi
+      click
+      cryptography
+      cssutils
+      defusedxml
+      flask
+      h11
+      httpcore
+      httpx
+      idna
+      itsdangerous
+      jinja2
+      markupsafe
+      more-itertools
+      packaging
+      pluggy
+      pycodestyle
+      pycparser
+      pyopenssl
+      pyparsing
+      pytest
+      python-dateutil
+      python-dotenv
+      soupsieve
+      stem
+      validators
+      waitress
+      wcwidth
+      werkzeug
+    ]
+    ++ httpx.optional-dependencies.http2
+    ++ httpx.optional-dependencies.socks;
 
   postInstall = ''
     # This creates renamed versions of the static files for cache busting,
diff --git a/pkgs/by-name/wt/wtfutil/package.nix b/pkgs/by-name/wt/wtfutil/package.nix
index 4246b93b0ea4..4ed70c5d0cd9 100644
--- a/pkgs/by-name/wt/wtfutil/package.nix
+++ b/pkgs/by-name/wt/wtfutil/package.nix
@@ -47,7 +47,7 @@ buildGoModule (finalAttrs: {
 
   doInstallCheck = true;
   # Darwin Error: mkdir /var/empty: file exists
-  nativeInstallCheckInputs = lib.optional (!stdenv.hostPlatform.isDarwin) [ versionCheckHook ];
+  nativeInstallCheckInputs = lib.optional (!stdenv.hostPlatform.isDarwin) versionCheckHook;
 
   passthru.updateScript = nix-update-script { };
 
diff --git a/pkgs/by-name/xp/xpra/package.nix b/pkgs/by-name/xp/xpra/package.nix
index 93eec2ec20c0..a4de10b06d8f 100644
--- a/pkgs/by-name/xp/xpra/package.nix
+++ b/pkgs/by-name/xp/xpra/package.nix
@@ -188,7 +188,7 @@ effectiveBuildPythonApplication rec {
     xxhash
     systemd
   ]
-  ++ lib.optional withNvenc [
+  ++ lib.optionals withNvenc [
     nvencHeaders
     nvjpegHeaders
   ];
diff --git a/pkgs/by-name/yc/ycmd/package.nix b/pkgs/by-name/yc/ycmd/package.nix
index cb6413ab6349..7b64a5f319b3 100644
--- a/pkgs/by-name/yc/ycmd/package.nix
+++ b/pkgs/by-name/yc/ycmd/package.nix
@@ -43,10 +43,10 @@ stdenv.mkDerivation {
     [
       abseil-cpp
       boost
-      libllvm.all
-      libclang.all
       legacy-cgi
     ]
+    ++ libllvm.all
+    ++ libclang.all
     ++ [
       jedi
       jedi-language-server
diff --git a/pkgs/desktops/pantheon/apps/switchboard/wrapper.nix b/pkgs/desktops/pantheon/apps/switchboard/wrapper.nix
index 4d3753946bcc..1bcb7cd0d9cb 100644
--- a/pkgs/desktops/pantheon/apps/switchboard/wrapper.nix
+++ b/pkgs/desktops/pantheon/apps/switchboard/wrapper.nix
@@ -40,7 +40,7 @@ stdenv.mkDerivation {
     wrapGAppsHook4
   ];
 
-  buildInputs = lib.forEach selectedPlugs (x: x.buildInputs) ++ selectedPlugs;
+  buildInputs = lib.concatMap (x: x.buildInputs) selectedPlugs ++ selectedPlugs;
 
   dontUnpack = true;
   dontConfigure = true;
diff --git a/pkgs/desktops/pantheon/desktop/wingpanel/wrapper.nix b/pkgs/desktops/pantheon/desktop/wingpanel/wrapper.nix
index cb089c3cd0c5..8bdbbffac072 100644
--- a/pkgs/desktops/pantheon/desktop/wingpanel/wrapper.nix
+++ b/pkgs/desktops/pantheon/desktop/wingpanel/wrapper.nix
@@ -37,7 +37,7 @@ stdenv.mkDerivation {
     wrapGAppsHook3
   ];
 
-  buildInputs = lib.forEach selectedIndicators (x: x.buildInputs) ++ selectedIndicators;
+  buildInputs = lib.concatMap (x: x.buildInputs) selectedIndicators ++ selectedIndicators;
 
   dontUnpack = true;
   dontConfigure = true;
diff --git a/pkgs/development/compilers/dotnet/wrapper.nix b/pkgs/development/compilers/dotnet/wrapper.nix
index 1e66c4dbd0de..260717a7ed66 100644
--- a/pkgs/development/compilers/dotnet/wrapper.nix
+++ b/pkgs/development/compilers/dotnet/wrapper.nix
@@ -223,7 +223,7 @@ stdenvNoCC.mkDerivation (finalAttrs: {
               buildInputs = [
                 zlib
               ]
-              ++ lib.optional stdenv.hostPlatform.isDarwin [
+              ++ lib.optionals stdenv.hostPlatform.isDarwin [
                 swiftPackages.swift
                 darwin.ICU
               ];
diff --git a/pkgs/development/haskell-modules/configuration-common.nix b/pkgs/development/haskell-modules/configuration-common.nix
index aa07149bf988..e8d9286f0706 100644
--- a/pkgs/development/haskell-modules/configuration-common.nix
+++ b/pkgs/development/haskell-modules/configuration-common.nix
@@ -1572,7 +1572,7 @@ with haskellLib;
   # https://github.com/mgajda/json-autotype/issues/25
   json-autotype = dontCheck super.json-autotype;
 
-  gargoyle-postgresql-nix = addBuildTool [ pkgs.postgresql ] super.gargoyle-postgresql-nix;
+  gargoyle-postgresql-nix = addBuildTool pkgs.postgresql super.gargoyle-postgresql-nix;
 
   # PortMidi needs an environment variable to have ALSA find its plugins:
   # https://github.com/NixOS/nixpkgs/issues/6860
diff --git a/pkgs/development/mobile/androidenv/tools.nix b/pkgs/development/mobile/androidenv/tools.nix
index df216fefdb17..efcbe8bdd6a1 100644
--- a/pkgs/development/mobile/androidenv/tools.nix
+++ b/pkgs/development/mobile/androidenv/tools.nix
@@ -17,7 +17,7 @@ deployAndroidPackage {
   name = "androidsdk-tools";
   inherit package os arch;
   nativeBuildInputs = [ makeWrapper ] ++ lib.optionals (os == "linux") [ autoPatchelfHook ];
-  buildInputs = lib.optional (os == "linux") (
+  buildInputs = lib.optionals (os == "linux") (
     (with pkgs; [
       glibc
       freetype
diff --git a/pkgs/development/octave-modules/io/default.nix b/pkgs/development/octave-modules/io/default.nix
index a4db56e12a42..ca3b8b642a61 100644
--- a/pkgs/development/octave-modules/io/default.nix
+++ b/pkgs/development/octave-modules/io/default.nix
@@ -16,9 +16,7 @@ buildOctavePackage rec {
     sha256 = "sha256-G49gAZ/lzir1YwEAPjBGRjNJ3VMxI+iXnsS0yev8f2s=";
   };
 
-  buildInputs = [
-    (lib.optional enableJava jdk)
-  ];
+  buildInputs = lib.optional enableJava jdk;
 
   propagatedBuildInputs = [
     unzip
diff --git a/pkgs/development/python-modules/drf-pydantic/default.nix b/pkgs/development/python-modules/drf-pydantic/default.nix
index 63543d888cf2..63a41b5c1795 100644
--- a/pkgs/development/python-modules/drf-pydantic/default.nix
+++ b/pkgs/development/python-modules/drf-pydantic/default.nix
@@ -35,8 +35,8 @@ buildPythonPackage rec {
   nativeCheckInputs = [
     pytestCheckHook
     pytest-cov-stub
-    pydantic.optional-dependencies.email
-  ];
+  ]
+  ++ pydantic.optional-dependencies.email;
 
   meta = {
     changelog = "https://github.com/georgebv/drf-pydantic/releases/tag/${src.tag}";
diff --git a/pkgs/development/python-modules/e3-core/default.nix b/pkgs/development/python-modules/e3-core/default.nix
index 8d8266310ab9..1e39e5afa04d 100644
--- a/pkgs/development/python-modules/e3-core/default.nix
+++ b/pkgs/development/python-modules/e3-core/default.nix
@@ -47,7 +47,7 @@ buildPythonPackage rec {
     stevedore
     tqdm
   ]
-  ++ lib.optional stdenv.hostPlatform.isLinux [
+  ++ lib.optionals stdenv.hostPlatform.isLinux [
     # See https://github.com/AdaCore/e3-core/blob/v22.6.0/pyproject.toml#L37-L42
     # These are required only on Linux. Darwin has its own set of requirements
     psutil
diff --git a/pkgs/development/python-modules/eth-keys/default.nix b/pkgs/development/python-modules/eth-keys/default.nix
index 7377ae5f925b..c5787c8703db 100644
--- a/pkgs/development/python-modules/eth-keys/default.nix
+++ b/pkgs/development/python-modules/eth-keys/default.nix
@@ -46,8 +46,8 @@ buildPythonPackage rec {
     pydantic
   ]
   ++ optional-dependencies.coincurve
-  ++ lib.optional (!isPyPy) eth-hash.optional-dependencies.pysha3
-  ++ lib.optional isPyPy eth-hash.optional-dependencies.pycryptodome;
+  ++ lib.optionals (!isPyPy) eth-hash.optional-dependencies.pysha3
+  ++ lib.optionals isPyPy eth-hash.optional-dependencies.pycryptodome;
 
   pythonImportsCheck = [ "eth_keys" ];
 
diff --git a/pkgs/development/python-modules/langchain-aws/default.nix b/pkgs/development/python-modules/langchain-aws/default.nix
index bfd8fd2ecc3b..1487685ad2c4 100644
--- a/pkgs/development/python-modules/langchain-aws/default.nix
+++ b/pkgs/development/python-modules/langchain-aws/default.nix
@@ -62,8 +62,7 @@ buildPythonPackage (finalAttrs: {
   ];
 
   optional-dependencies = {
-    anthropic = [
-      anthropic.optional-dependencies.bedrock
+    anthropic = anthropic.optional-dependencies.bedrock ++ [
       langchain-anthropic
     ];
   };
diff --git a/pkgs/development/python-modules/mayim/default.nix b/pkgs/development/python-modules/mayim/default.nix
index 028ed296da2d..8fdcee438141 100644
--- a/pkgs/development/python-modules/mayim/default.nix
+++ b/pkgs/development/python-modules/mayim/default.nix
@@ -44,11 +44,14 @@ buildPythonPackage rec {
     pytest-asyncio
     pytest-cov-stub
   ]
-  ++ (with optional-dependencies; [
-    postgres
-    mysql
-    sqlite
-  ]);
+  ++ (
+    with optional-dependencies;
+    lib.concatLists [
+      postgres
+      mysql
+      sqlite
+    ]
+  );
 
   pythonImportsCheck = [ "mayim" ];
 
diff --git a/pkgs/development/python-modules/shiboken6/default.nix b/pkgs/development/python-modules/shiboken6/default.nix
index e4f85d57adb9..7492add38e8e 100644
--- a/pkgs/development/python-modules/shiboken6/default.nix
+++ b/pkgs/development/python-modules/shiboken6/default.nix
@@ -34,9 +34,7 @@ stdenv'.mkDerivation (finalAttrs: {
   buildInputs = [
     python.pkgs.qt6.qtbase
   ]
-  ++ lib.optionals stdenv.hostPlatform.isDarwin [
-    python.pkgs.qt6.darwinVersionInputs
-  ];
+  ++ lib.optionals stdenv.hostPlatform.isDarwin python.pkgs.qt6.darwinVersionInputs;
 
   cmakeFlags = [
     "-DBUILD_TESTS=OFF"
diff --git a/pkgs/development/python-modules/swh-core/default.nix b/pkgs/development/python-modules/swh-core/default.nix
index 8f0e90a34136..fd2590ff4cea 100644
--- a/pkgs/development/python-modules/swh-core/default.nix
+++ b/pkgs/development/python-modules/swh-core/default.nix
@@ -101,7 +101,6 @@ buildPythonPackage (finalAttrs: {
     msgpack
     postgresql
     postgresqlTestHook
-    psycopg.optional-dependencies.pool
     pylzma
     pytestCheckHook
     pytest-aiohttp
@@ -119,7 +118,8 @@ buildPythonPackage (finalAttrs: {
     types-requests
     unzip
     pkgs.zstd
-  ];
+  ]
+  ++ psycopg.optional-dependencies.pool;
 
   disabledTestPaths = lib.optionals (pythonAtLeast "3.14") [
     # shutil.RegistryError: .tar.zst is already registered for "zstdtar"
diff --git a/pkgs/development/python-modules/uptime-kuma-api/default.nix b/pkgs/development/python-modules/uptime-kuma-api/default.nix
index 816eb2ebe254..bfe9f77cba58 100644
--- a/pkgs/development/python-modules/uptime-kuma-api/default.nix
+++ b/pkgs/development/python-modules/uptime-kuma-api/default.nix
@@ -20,8 +20,8 @@ buildPythonPackage rec {
   propagatedBuildInputs = [
     packaging
     python-socketio
-    python-socketio.optional-dependencies.client
-  ];
+  ]
+  ++ python-socketio.optional-dependencies.client;
 
   pythonImportsCheck = [ "uptime_kuma_api" ];
 
diff --git a/pkgs/development/ruby-modules/with-packages/default.nix b/pkgs/development/ruby-modules/with-packages/default.nix
index 8e63fa12edaa..5f3d87aefb71 100644
--- a/pkgs/development/ruby-modules/with-packages/default.nix
+++ b/pkgs/development/ruby-modules/with-packages/default.nix
@@ -77,9 +77,9 @@ let
       name = "${ruby.name}-with-packages";
       nativeBuildInputs = [ makeBinaryWrapper ];
       buildInputs = [
-        selected
         ruby
-      ];
+      ]
+      ++ selected;
 
       dontUnpack = true;
 
diff --git a/pkgs/development/tools/godot/common.nix b/pkgs/development/tools/godot/common.nix
index 1cfcd31d5996..f2d068f68adc 100644
--- a/pkgs/development/tools/godot/common.nix
+++ b/pkgs/development/tools/godot/common.nix
@@ -620,7 +620,7 @@ let
           scons
         ]
         ++ lib.optionals withWayland [ wayland-scanner ]
-        ++ lib.optional (editor && withMono) [
+        ++ lib.optionals (editor && withMono) [
           makeWrapper
           dotnet-sdk
         ]
diff --git a/pkgs/os-specific/linux/drbd/driver.nix b/pkgs/os-specific/linux/drbd/driver.nix
index 04dfa1b51a10..612dfc0c4fa2 100644
--- a/pkgs/os-specific/linux/drbd/driver.nix
+++ b/pkgs/os-specific/linux/drbd/driver.nix
@@ -21,8 +21,7 @@ stdenv.mkDerivation (finalAttrs: {
 
   hardeningDisable = [ "pic" ];
 
-  nativeBuildInputs = [
-    kernel.moduleBuildDependencies
+  nativeBuildInputs = kernel.moduleBuildDependencies ++ [
     flex
     coccinelle
     python3
diff --git a/pkgs/servers/home-assistant/tests.nix b/pkgs/servers/home-assistant/tests.nix
index 6cc038efdb63..e37423ade9c8 100644
--- a/pkgs/servers/home-assistant/tests.nix
+++ b/pkgs/servers/home-assistant/tests.nix
@@ -6,10 +6,11 @@
 
 let
   getComponentDeps = component: home-assistant.getPackages component home-assistant.python.pkgs;
+  inherit (lib) concatMap;
 
   # some components' tests have additional dependencies
   extraCheckInputs = with home-assistant.python.pkgs; {
-    alexa = map getComponentDeps [
+    alexa = concatMap getComponentDeps [
       "cloud"
       "frontend"
       "stream"
@@ -50,7 +51,7 @@ let
       pychromecast
     ];
     lutron_caseta = getComponentDeps "frontend";
-    mastodon = map getComponentDeps [
+    mastodon = concatMap getComponentDeps [
       "stream"
     ];
     miele = getComponentDeps "cloud";
diff --git a/pkgs/stdenv/generic/make-derivation.nix b/pkgs/stdenv/generic/make-derivation.nix
index 7df90e856846..e1680f07cfa4 100644
--- a/pkgs/stdenv/generic/make-derivation.nix
+++ b/pkgs/stdenv/generic/make-derivation.nix
@@ -52,6 +52,7 @@ let
     unique
     unsafeDiscardStringContext
     unsafeGetAttrPos
+    warn
     warnIf
     zipAttrsWith
     ;
@@ -482,7 +483,12 @@ let
             if isSingularDependency dep then
               index + 1
             else if isList dep then
-              seq (checkDependencyList' ([ index ] ++ positions) name dep) (index + 1)
+              warn
+                ''
+                  Dependency of package '${attrs.name or attrs.pname}' uses a nested list in attribute '${name}'.
+                  This is deprecated as of Nixpkgs release 26.05, and support will
+                  be removed in a future nixpkgs release.''
+                (seq (checkDependencyList' ([ index ] ++ positions) name dep) (index + 1))
             else
               throw "Dependency is not of a valid type: ${
                 concatMapStrings (ix: "element ${toString ix} of ") ([ index ] ++ positions)
diff --git a/pkgs/tools/package-management/lix/common-nix-eval-jobs.nix b/pkgs/tools/package-management/lix/common-nix-eval-jobs.nix
index 48b76ca7179b..b43526bcc264 100644
--- a/pkgs/tools/package-management/lix/common-nix-eval-jobs.nix
+++ b/pkgs/tools/package-management/lix/common-nix-eval-jobs.nix
@@ -40,7 +40,7 @@ stdenv.mkDerivation {
     # nlohmann_json can be only discovered via cmake files
     cmake
   ]
-  ++ (lib.optional stdenv.cc.isClang [ buildPackages.clang-tools ]);
+  ++ (lib.optional stdenv.cc.isClang buildPackages.clang-tools);
 
   # point 'nix edit' and ofborg at the file that defines the attribute,
   # not this common file.