diff --git a/pkgs/applications/audio/cd-discid/default.nix b/pkgs/applications/audio/cd-discid/default.nix
index 2cf9849e351b..382d4a1b6675 100644
--- a/pkgs/applications/audio/cd-discid/default.nix
+++ b/pkgs/applications/audio/cd-discid/default.nix
@@ -13,7 +13,7 @@ stdenv.mkDerivation rec {
   installFlags = "PREFIX=$(out) INSTALL=install";
 
   buildInputs = []
-    ++ stdenv.lib.optional stdenv.isDarwin [ IOKit ];
+    ++ stdenv.lib.optional stdenv.isDarwin IOKit;
 
   meta = with stdenv.lib; {
     homepage = http://linukz.org/cd-discid.shtml;
diff --git a/pkgs/applications/graphics/feh/default.nix b/pkgs/applications/graphics/feh/default.nix
index 380e5d298864..40fe178d6257 100644
--- a/pkgs/applications/graphics/feh/default.nix
+++ b/pkgs/applications/graphics/feh/default.nix
@@ -12,7 +12,7 @@ stdenv.mkDerivation rec {
   outputs = [ "out" "doc" ];
 
   nativeBuildInputs = [ makeWrapper xorg.libXt ]
-    ++ stdenv.lib.optional doCheck [ perlPackages.TestCommand perlPackages.TestHarness ];
+    ++ stdenv.lib.optionals doCheck [ perlPackages.TestCommand perlPackages.TestHarness ];
 
   buildInputs = [ xorg.libX11 xorg.libXinerama imlib2 libjpeg libpng curl libexif ];
 
diff --git a/pkgs/applications/networking/cluster/spark/default.nix b/pkgs/applications/networking/cluster/spark/default.nix
index 79074d2d28e6..b4c20e22680b 100644
--- a/pkgs/applications/networking/cluster/spark/default.nix
+++ b/pkgs/applications/networking/cluster/spark/default.nix
@@ -14,7 +14,7 @@ stdenv.mkDerivation rec {
   };
 
   buildInputs = [ makeWrapper jre pythonPackages.python pythonPackages.numpy ]
-    ++ optional mesosSupport [ mesos ];
+    ++ optional mesosSupport mesos;
 
   untarDir = "${name}-bin-cdh4";
   installPhase = ''
diff --git a/pkgs/applications/networking/mumble/default.nix b/pkgs/applications/networking/mumble/default.nix
index fff0bc5edc46..038f4cb1a739 100644
--- a/pkgs/applications/networking/mumble/default.nix
+++ b/pkgs/applications/networking/mumble/default.nix
@@ -104,7 +104,7 @@ let
       "CONFIG+=no-client"
     ];
 
-    buildInputs = [ libcap ] ++ optional iceSupport [ zeroc_ice ];
+    buildInputs = [ libcap ] ++ optional iceSupport zeroc_ice;
   };
 
   stableSource = rec {
diff --git a/pkgs/development/libraries/gtk+/3.x.nix b/pkgs/development/libraries/gtk+/3.x.nix
index 1ac006b21617..df223688d46d 100644
--- a/pkgs/development/libraries/gtk+/3.x.nix
+++ b/pkgs/development/libraries/gtk+/3.x.nix
@@ -36,7 +36,7 @@ stdenv.mkDerivation rec {
     [ expat glib cairo pango gdk_pixbuf atk at_spi2_atk
       libXrandr libXrender libXcomposite libXi libXcursor libSM libICE ]
     ++ optionals waylandSupport [ wayland wayland-protocols ]
-    ++ optional stdenv.isDarwin (with darwin.apple_sdk.frameworks; [ AppKit Cocoa ])
+    ++ optionals stdenv.isDarwin (with darwin.apple_sdk.frameworks; [ AppKit Cocoa ])
     ++ optional xineramaSupport libXinerama
     ++ optional cupsSupport cups;
   #TODO: colord?
diff --git a/pkgs/development/libraries/librsvg/default.nix b/pkgs/development/libraries/librsvg/default.nix
index d5df00a7e9ba..409307fb52b0 100644
--- a/pkgs/development/libraries/librsvg/default.nix
+++ b/pkgs/development/libraries/librsvg/default.nix
@@ -18,7 +18,7 @@ stdenv.mkDerivation rec {
   outputs = [ "out" "dev" ];
 
   buildInputs = [ libxml2 libgsf bzip2 libcroco pango libintlOrEmpty ]
-    ++ stdenv.lib.optional enableIntrospection [ gobjectIntrospection ];
+    ++ stdenv.lib.optional enableIntrospection gobjectIntrospection;
 
   propagatedBuildInputs = [ glib gdk_pixbuf cairo ] ++ lib.optional withGTK gtk3;
 
diff --git a/pkgs/development/libraries/openal-soft/default.nix b/pkgs/development/libraries/openal-soft/default.nix
index 4a466ad133ac..c17c224415db 100644
--- a/pkgs/development/libraries/openal-soft/default.nix
+++ b/pkgs/development/libraries/openal-soft/default.nix
@@ -21,7 +21,7 @@ stdenv.mkDerivation rec {
   buildInputs = [ cmake ]
     ++ optional alsaSupport alsaLib
     ++ optional pulseSupport libpulseaudio
-    ++ optional stdenv.isDarwin [ CoreServices AudioUnit AudioToolbox ];
+    ++ optionals stdenv.isDarwin [ CoreServices AudioUnit AudioToolbox ];
 
   NIX_LDFLAGS = []
     ++ optional alsaSupport "-lasound"
diff --git a/pkgs/development/libraries/png++/default.nix b/pkgs/development/libraries/png++/default.nix
index baebce8e4b11..6ca4734a4f7d 100644
--- a/pkgs/development/libraries/png++/default.nix
+++ b/pkgs/development/libraries/png++/default.nix
@@ -22,7 +22,7 @@ stdenv.mkDerivation rec {
   postCheck = "cat test/test.log";
 
   buildInputs = [ ]
-    ++ stdenv.lib.optional docSupport [ doxygen ];
+    ++ stdenv.lib.optional docSupport doxygen;
 
   propagatedBuildInputs = [ libpng ];
 
diff --git a/pkgs/games/openttd/default.nix b/pkgs/games/openttd/default.nix
index c40337d54f52..0c129f8d556f 100644
--- a/pkgs/games/openttd/default.nix
+++ b/pkgs/games/openttd/default.nix
@@ -38,7 +38,7 @@ stdenv.mkDerivation rec {
 
   nativeBuildInputs = [ pkgconfig makeWrapper ];
   buildInputs = [ SDL libpng xz zlib freetype fontconfig ]
-    ++ stdenv.lib.optional withFluidSynth [ fluidsynth soundfont-fluid ];
+    ++ stdenv.lib.optionals withFluidSynth [ fluidsynth soundfont-fluid ];
 
   prefixKey = "--prefix-dir=";
 
diff --git a/pkgs/tools/networking/openssh/default.nix b/pkgs/tools/networking/openssh/default.nix
index a6e4b7c4c209..0c19822d37c9 100644
--- a/pkgs/tools/networking/openssh/default.nix
+++ b/pkgs/tools/networking/openssh/default.nix
@@ -53,7 +53,7 @@ stdenv.mkDerivation rec {
     ++ optional withGssapiPatches gssapiSrc;
 
   buildInputs = [ zlib openssl libedit pkgconfig pam ]
-    ++ optional withKerberos [ kerberos ];
+    ++ optional withKerberos kerberos;
 
   # I set --disable-strip because later we strip anyway. And it fails to strip
   # properly when cross building.
diff --git a/pkgs/tools/networking/swec/default.nix b/pkgs/tools/networking/swec/default.nix
index 851af6f24f6f..5b7f8f114df3 100644
--- a/pkgs/tools/networking/swec/default.nix
+++ b/pkgs/tools/networking/swec/default.nix
@@ -10,7 +10,7 @@ stdenv.mkDerivation rec {
   };
 
   buildInputs = [ makeWrapper perl LWP URI HTMLParser ]
-   ++ stdenv.lib.optional doCheck [ HTTPServerSimple Parent ];
+   ++ stdenv.lib.optionals doCheck [ HTTPServerSimple Parent ];
 
   configurePhase = ''
     for i in swec tests/{runTests,testServer}
diff --git a/pkgs/tools/video/atomicparsley/default.nix b/pkgs/tools/video/atomicparsley/default.nix
index bb44fe044e81..835cacf0098c 100644
--- a/pkgs/tools/video/atomicparsley/default.nix
+++ b/pkgs/tools/video/atomicparsley/default.nix
@@ -11,7 +11,7 @@ stdenv.mkDerivation rec {
   };
 
   buildInputs = with pkgs; [ unzip ]
-    ++ stdenv.lib.optional stdenv.isDarwin [ darwin.apple_sdk.frameworks.Cocoa ];
+    ++ stdenv.lib.optionals stdenv.isDarwin [ darwin.apple_sdk.frameworks.Cocoa ];
   patches = [ ./casts.patch ];
   setSourceRoot = "sourceRoot=${product}-source-${version}";
   buildPhase = "bash build";
diff --git a/pkgs/top-level/perl-packages.nix b/pkgs/top-level/perl-packages.nix
index 96d92f40ca8b..c02693422761 100644
--- a/pkgs/top-level/perl-packages.nix
+++ b/pkgs/top-level/perl-packages.nix
@@ -32,7 +32,7 @@ let self = _self // overrides; _self = with self; {
     };
     outputs = ["out" "doc"];
     # use gnused so that the preCheck command passes
-    buildInputs = stdenv.lib.optional stdenv.isDarwin [ gnused ];
+    buildInputs = stdenv.lib.optional stdenv.isDarwin gnused;
     propagatedBuildInputs = [ FileNext ];
     meta = with stdenv.lib; {
       description = "A grep-like tool tailored to working with large trees of source code";
diff --git a/pkgs/top-level/python-packages.nix b/pkgs/top-level/python-packages.nix
index 2055160ab302..d88af031135a 100644
--- a/pkgs/top-level/python-packages.nix
+++ b/pkgs/top-level/python-packages.nix
@@ -2016,7 +2016,7 @@ in modules // {
     };
 
     propagatedBuildInputs = with stdenv.lib; with pkgs; [ modules.curses zlib xz ncompress gzip bzip2 gnutar p7zip cabextract lzma self.pycrypto ]
-      ++ optional visualizationSupport [ pyqtgraph ];
+      ++ optional visualizationSupport pyqtgraph;
 
     meta = with stdenv.lib; {
       homepage = "http://binwalk.org";