diff --git a/lib/attrsets.nix b/lib/attrsets.nix
index dca39cf79ffa..0066fba362ae 100644
--- a/lib/attrsets.nix
+++ b/lib/attrsets.nix
@@ -3,9 +3,9 @@
 
 let
   inherit (builtins) head tail length;
-  inherit (lib.trivial) and or;
+  inherit (lib.trivial) and;
   inherit (lib.strings) concatStringsSep;
-  inherit (lib.lists) fold concatMap concatLists all deepSeqList;
+  inherit (lib.lists) fold concatMap concatLists;
 in
 
 rec {
diff --git a/lib/composable-derivation.nix b/lib/composable-derivation.nix
index 5e55ac023f14..cb1fdc121e11 100644
--- a/lib/composable-derivation.nix
+++ b/lib/composable-derivation.nix
@@ -1,5 +1,5 @@
 {lib, pkgs}:
-let inherit (lib) nv nvs; in
+let inherit (lib) nvs; in
 {
 
   # composableDerivation basically mixes these features:
diff --git a/lib/customisation.nix b/lib/customisation.nix
index d942f54ee798..480280428909 100644
--- a/lib/customisation.nix
+++ b/lib/customisation.nix
@@ -1,9 +1,4 @@
 { lib }:
-let
-
-  inherit (builtins) attrNames;
-
-in
 
 rec {
 
diff --git a/lib/types.nix b/lib/types.nix
index 98eff2ac6ffb..4d6ac51c8988 100644
--- a/lib/types.nix
+++ b/lib/types.nix
@@ -8,7 +8,7 @@ with lib.trivial;
 with lib.strings;
 let
 
-  inherit (lib.modules) mergeDefinitions filterOverrides;
+  inherit (lib.modules) mergeDefinitions;
   outer_types =
 rec {
   isType = type: x: (x._type or "") == type;
diff --git a/nixos/modules/programs/tmux.nix b/nixos/modules/programs/tmux.nix
index 4a60403a2827..3d5a37274ae2 100644
--- a/nixos/modules/programs/tmux.nix
+++ b/nixos/modules/programs/tmux.nix
@@ -1,7 +1,7 @@
 { config, pkgs, lib, ... }:
 
 let
-  inherit (lib) mkOption mkEnableOption mkIf mkMerge types;
+  inherit (lib) mkOption mkIf types;
 
   cfg = config.programs.tmux;
 
diff --git a/nixos/modules/security/pam_usb.nix b/nixos/modules/security/pam_usb.nix
index 9bc73bf0b85c..c695ba075ca9 100644
--- a/nixos/modules/security/pam_usb.nix
+++ b/nixos/modules/security/pam_usb.nix
@@ -4,8 +4,6 @@ with lib;
 
 let
 
-  inherit (pkgs) pam_usb;
-
   cfg = config.security.pam.usb;
 
   anyUsbAuth = any (attrByPath ["usbAuth"] false) (attrValues config.security.pam.services);
diff --git a/nixos/modules/services/hardware/udev.nix b/nixos/modules/services/hardware/udev.nix
index 7bfc3bb64872..0266286aaacf 100644
--- a/nixos/modules/services/hardware/udev.nix
+++ b/nixos/modules/services/hardware/udev.nix
@@ -4,8 +4,6 @@ with lib;
 
 let
 
-  inherit (pkgs) stdenv writeText procps;
-
   udev = config.systemd.package;
 
   cfg = config.services.udev;
diff --git a/nixos/modules/services/monitoring/uptime.nix b/nixos/modules/services/monitoring/uptime.nix
index 29616a085c8f..b4d3a2640109 100644
--- a/nixos/modules/services/monitoring/uptime.nix
+++ b/nixos/modules/services/monitoring/uptime.nix
@@ -1,6 +1,6 @@
 { config, pkgs, lib, ... }:
 let
-  inherit (lib) mkOption mkEnableOption mkIf mkMerge types optionalAttrs optional;
+  inherit (lib) mkOption mkEnableOption mkIf mkMerge types optional;
 
   cfg = config.services.uptime;
 
diff --git a/nixos/modules/services/network-filesystems/openafs/lib.nix b/nixos/modules/services/network-filesystems/openafs/lib.nix
index 255740ac65ef..cc68eea91f2d 100644
--- a/nixos/modules/services/network-filesystems/openafs/lib.nix
+++ b/nixos/modules/services/network-filesystems/openafs/lib.nix
@@ -1,7 +1,7 @@
 { config, lib, pkgs, ...}:
 
 let
-  inherit (lib) concatStringsSep getBin mkOption types;
+  inherit (lib) concatStringsSep mkOption types;
 
 in rec {
 
diff --git a/nixos/modules/services/network-filesystems/openafs/server.nix b/nixos/modules/services/network-filesystems/openafs/server.nix
index aa8640fd240e..4c80ed0839f7 100644
--- a/nixos/modules/services/network-filesystems/openafs/server.nix
+++ b/nixos/modules/services/network-filesystems/openafs/server.nix
@@ -4,7 +4,7 @@
 with import ./lib.nix { inherit config lib pkgs; };
 
 let
-  inherit (lib) concatStringsSep intersperse mapAttrsToList mkForce mkIf mkMerge mkOption optionalString types;
+  inherit (lib) concatStringsSep mkIf mkOption optionalString types;
 
   bosConfig = pkgs.writeText "BosConfig" (''
     restrictmode 1
diff --git a/nixos/modules/services/networking/chrony.nix b/nixos/modules/services/networking/chrony.nix
index 6a89002b42de..cef30661cc33 100644
--- a/nixos/modules/services/networking/chrony.nix
+++ b/nixos/modules/services/networking/chrony.nix
@@ -4,8 +4,6 @@ with lib;
 
 let
 
-  inherit (pkgs) chrony;
-
   stateDir = "/var/lib/chrony";
 
   keyFile = "/etc/chrony.keys";
diff --git a/nixos/modules/services/system/kerberos.nix b/nixos/modules/services/system/kerberos.nix
index d85dee089827..d151385d2f9b 100644
--- a/nixos/modules/services/system/kerberos.nix
+++ b/nixos/modules/services/system/kerberos.nix
@@ -2,7 +2,7 @@
 
 let
 
-  inherit (lib) mkOption mkIf singleton;
+  inherit (lib) mkOption mkIf;
 
   inherit (pkgs) heimdalFull;
 
diff --git a/nixos/modules/services/system/nscd.nix b/nixos/modules/services/system/nscd.nix
index 11a30ea81ba9..fd1570d11980 100644
--- a/nixos/modules/services/system/nscd.nix
+++ b/nixos/modules/services/system/nscd.nix
@@ -7,8 +7,6 @@ let
   nssModulesPath = config.system.nssModules.path;
   cfg = config.services.nscd;
 
-  inherit (lib) singleton;
-
 in
 
 {
diff --git a/nixos/modules/services/ttys/kmscon.nix b/nixos/modules/services/ttys/kmscon.nix
index 88e488425bce..59c45fcb44ee 100644
--- a/nixos/modules/services/ttys/kmscon.nix
+++ b/nixos/modules/services/ttys/kmscon.nix
@@ -1,6 +1,6 @@
 { config, pkgs, lib, ... }:
 let
-  inherit (lib) mkOption types mkIf optionalString;
+  inherit (lib) mkOption types mkIf;
 
   cfg = config.services.kmscon;
 
diff --git a/nixos/modules/services/x11/desktop-managers/plasma5.nix b/nixos/modules/services/x11/desktop-managers/plasma5.nix
index 4b9e561d53c8..17733aa7e4f6 100644
--- a/nixos/modules/services/x11/desktop-managers/plasma5.nix
+++ b/nixos/modules/services/x11/desktop-managers/plasma5.nix
@@ -7,7 +7,7 @@ let
   xcfg = config.services.xserver;
   cfg = xcfg.desktopManager.plasma5;
 
-  inherit (pkgs) kdeApplications plasma5 libsForQt5 qt5 xorg;
+  inherit (pkgs) kdeApplications plasma5 libsForQt5 qt5;
 
 in
 
diff --git a/nixos/modules/services/x11/display-managers/lightdm-greeters/gtk.nix b/nixos/modules/services/x11/display-managers/lightdm-greeters/gtk.nix
index 2a71d2338607..385f20b7e066 100644
--- a/nixos/modules/services/x11/display-managers/lightdm-greeters/gtk.nix
+++ b/nixos/modules/services/x11/display-managers/lightdm-greeters/gtk.nix
@@ -8,7 +8,7 @@ let
   ldmcfg = dmcfg.lightdm;
   cfg = ldmcfg.greeters.gtk;
 
-  inherit (pkgs) stdenv lightdm writeScript writeText;
+  inherit (pkgs) writeText;
 
   theme = cfg.theme.package;
   icons = cfg.iconTheme.package;
diff --git a/nixos/modules/services/x11/display-managers/lightdm.nix b/nixos/modules/services/x11/display-managers/lightdm.nix
index 206ede227efa..54d4520a0c8b 100644
--- a/nixos/modules/services/x11/display-managers/lightdm.nix
+++ b/nixos/modules/services/x11/display-managers/lightdm.nix
@@ -13,7 +13,7 @@ let
   wmDefault = xcfg.windowManager.default;
   hasDefaultUserSession = dmDefault != "none" || wmDefault != "none";
 
-  inherit (pkgs) stdenv lightdm writeScript writeText;
+  inherit (pkgs) lightdm writeScript writeText;
 
   # lightdm runs with clearenv(), but we need a few things in the enviornment for X to startup
   xserverWrapper = writeScript "xserver-wrapper"
diff --git a/nixos/modules/services/x11/window-managers/openbox.nix b/nixos/modules/services/x11/window-managers/openbox.nix
index 07ef77151e95..165772d1aa09 100644
--- a/nixos/modules/services/x11/window-managers/openbox.nix
+++ b/nixos/modules/services/x11/window-managers/openbox.nix
@@ -2,7 +2,6 @@
 
 with lib;
 let
-  inherit (lib) mkOption mkIf;
   cfg = config.services.xserver.windowManager.openbox;
 in
 
diff --git a/nixos/modules/services/x11/window-managers/wmii.nix b/nixos/modules/services/x11/window-managers/wmii.nix
index 30c8df782245..eec6f2b2b81b 100644
--- a/nixos/modules/services/x11/window-managers/wmii.nix
+++ b/nixos/modules/services/x11/window-managers/wmii.nix
@@ -2,7 +2,6 @@
 
 with lib;
 let
-  inherit (lib) mkOption mkIf singleton;
   cfg = config.services.xserver.windowManager.wmii;
   wmii = pkgs.wmii_hg;
 in
diff --git a/pkgs/applications/audio/sonata/default.nix b/pkgs/applications/audio/sonata/default.nix
index a3d418cd4fe4..8c5bab40b459 100644
--- a/pkgs/applications/audio/sonata/default.nix
+++ b/pkgs/applications/audio/sonata/default.nix
@@ -2,7 +2,7 @@
 , python3Packages, gnome3, gtk3, gobjectIntrospection}:
 
 let
-  inherit (python3Packages) buildPythonApplication python isPy3k dbus-python pygobject3 mpd2;
+  inherit (python3Packages) buildPythonApplication isPy3k dbus-python pygobject3 mpd2;
 in buildPythonApplication rec {
   pname = "sonata";
   version = "1.7b1";
diff --git a/pkgs/applications/networking/browsers/chromium/default.nix b/pkgs/applications/networking/browsers/chromium/default.nix
index d2bb04251705..51618a479d42 100644
--- a/pkgs/applications/networking/browsers/chromium/default.nix
+++ b/pkgs/applications/networking/browsers/chromium/default.nix
@@ -64,8 +64,6 @@ let
 
   version = chromium.browser.version;
 
-  inherit (stdenv.lib) versionAtLeast;
-
 in stdenv.mkDerivation {
   name = "chromium${suffix}-${version}";
   inherit version;
diff --git a/pkgs/applications/networking/instant-messengers/zoom-us/default.nix b/pkgs/applications/networking/instant-messengers/zoom-us/default.nix
index 196cbb70b4e1..72812563b099 100644
--- a/pkgs/applications/networking/instant-messengers/zoom-us/default.nix
+++ b/pkgs/applications/networking/instant-messengers/zoom-us/default.nix
@@ -11,8 +11,7 @@
 assert pulseaudioSupport -> libpulseaudio != null;
 
 let
-  inherit (stdenv.lib) concatStringsSep makeBinPath makeLibraryPath
-    makeSearchPath optional optionalString;
+  inherit (stdenv.lib) concatStringsSep makeBinPath optional;
 
   version = "2.2.128200.0702";
   srcs = {
diff --git a/pkgs/applications/networking/irc/weechat/default.nix b/pkgs/applications/networking/irc/weechat/default.nix
index a672fa73c4f0..89b9893085ca 100644
--- a/pkgs/applications/networking/irc/weechat/default.nix
+++ b/pkgs/applications/networking/irc/weechat/default.nix
@@ -15,7 +15,7 @@
 , runCommand }:
 
 let
-  inherit (pythonPackages) python pycrypto pync;
+  inherit (pythonPackages) python;
   plugins = [
     { name = "perl"; enabled = perlSupport; cmakeFlag = "ENABLE_PERL"; buildInputs = [ perl ]; }
     { name = "tcl"; enabled = tclSupport; cmakeFlag = "ENABLE_TCL"; buildInputs = [ tcl ]; }
diff --git a/pkgs/applications/science/logic/acgtk/default.nix b/pkgs/applications/science/logic/acgtk/default.nix
index 9e6243c54980..b787a4e7a01c 100644
--- a/pkgs/applications/science/logic/acgtk/default.nix
+++ b/pkgs/applications/science/logic/acgtk/default.nix
@@ -4,8 +4,7 @@
   installExamples ? true,
   installEmacsMode ? true }:
 
-let inherit (stdenv.lib) versionAtLeast
-                         optionals optionalString; in
+let inherit (stdenv.lib) versionAtLeast optionalString; in
 
 let inherit (ocamlPackages) ocaml camlp4; in
 
diff --git a/pkgs/applications/science/math/sage/default.nix b/pkgs/applications/science/math/sage/default.nix
index 1f540cc2b287..63b751b814ee 100644
--- a/pkgs/applications/science/math/sage/default.nix
+++ b/pkgs/applications/science/math/sage/default.nix
@@ -3,7 +3,7 @@
 }:
 
 let
-  inherit (nixpkgs) fetchpatch fetchurl symlinkJoin fetchFromGitHub callPackage nodePackages_8_x;
+  inherit (nixpkgs) fetchpatch fetchurl symlinkJoin callPackage nodePackages_8_x;
 
   # https://trac.sagemath.org/ticket/15980 for tracking of python3 support
   python = nixpkgs.python2.override {
diff --git a/pkgs/applications/version-management/git-and-tools/git-cola/default.nix b/pkgs/applications/version-management/git-and-tools/git-cola/default.nix
index 391ca26de257..860b7b7dd0c9 100644
--- a/pkgs/applications/version-management/git-and-tools/git-cola/default.nix
+++ b/pkgs/applications/version-management/git-and-tools/git-cola/default.nix
@@ -1,7 +1,7 @@
 { stdenv, fetchFromGitHub, pythonPackages, makeWrapper, gettext, git }:
 
 let
-  inherit (pythonPackages) buildPythonApplication pyqt5 sip pyinotify python mock;
+  inherit (pythonPackages) buildPythonApplication pyqt5 sip pyinotify;
 in buildPythonApplication rec {
   name = "git-cola-${version}";
   version = "3.1";
diff --git a/pkgs/build-support/build-maven.nix b/pkgs/build-support/build-maven.nix
index ba85428ba8c4..30df3e8e7336 100644
--- a/pkgs/build-support/build-maven.nix
+++ b/pkgs/build-support/build-maven.nix
@@ -17,7 +17,7 @@ infoFile: let
     ${lib.concatStrings (map (dep: let
       inherit (dep)
         url sha1 groupId artifactId version
-        authenticated metadata extension repository-id;
+        authenticated metadata repository-id;
 
       versionDir = dep.unresolved-version or version;
 
diff --git a/pkgs/development/beam-modules/default.nix b/pkgs/development/beam-modules/default.nix
index 83de6f9e5697..f10c8ec86ff9 100644
--- a/pkgs/development/beam-modules/default.nix
+++ b/pkgs/development/beam-modules/default.nix
@@ -1,7 +1,7 @@
 { stdenv, pkgs, erlang }:
 
 let
-  inherit (stdenv.lib) getVersion versionAtLeast makeExtensible;
+  inherit (stdenv.lib) makeExtensible;
 
   lib = pkgs.callPackage ./lib.nix {};
 
diff --git a/pkgs/development/beam-modules/lib.nix b/pkgs/development/beam-modules/lib.nix
index d6b83cb1af04..db40c47794fa 100644
--- a/pkgs/development/beam-modules/lib.nix
+++ b/pkgs/development/beam-modules/lib.nix
@@ -49,7 +49,6 @@ rec {
   */
   callElixir = drv: args:
     let
-      inherit (stdenv.lib) versionAtLeast;
       builder = callPackage ../interpreters/elixir/generic-builder.nix args;
     in
       callPackage drv {
@@ -71,7 +70,6 @@ rec {
   */
   callLFE = drv: args:
     let
-      inherit (stdenv.lib) versionAtLeast;
       builder = callPackage ../interpreters/lfe/generic-builder.nix args;
     in
       callPackage drv {
diff --git a/pkgs/development/compilers/go/1.10.nix b/pkgs/development/compilers/go/1.10.nix
index b4fa005c3de8..0958bdeb0c1f 100644
--- a/pkgs/development/compilers/go/1.10.nix
+++ b/pkgs/development/compilers/go/1.10.nix
@@ -6,7 +6,7 @@
 
 let
 
-  inherit (stdenv.lib) optional optionals optionalString;
+  inherit (stdenv.lib) optionals optionalString;
 
   clangHack = writeScriptBin "clang" ''
     #!${stdenv.shell}
diff --git a/pkgs/development/compilers/go/1.9.nix b/pkgs/development/compilers/go/1.9.nix
index 8ef528e2c92a..6acedecb2116 100644
--- a/pkgs/development/compilers/go/1.9.nix
+++ b/pkgs/development/compilers/go/1.9.nix
@@ -6,7 +6,7 @@
 
 let
 
-  inherit (stdenv.lib) optional optionals optionalString;
+  inherit (stdenv.lib) optionals optionalString;
 
   clangHack = writeScriptBin "clang" ''
     #!${stdenv.shell}
diff --git a/pkgs/development/compilers/ocaml/ber-metaocaml-104.nix b/pkgs/development/compilers/ocaml/ber-metaocaml-104.nix
index e084a2dcf94b..e6c688940368 100644
--- a/pkgs/development/compilers/ocaml/ber-metaocaml-104.nix
+++ b/pkgs/development/compilers/ocaml/ber-metaocaml-104.nix
@@ -2,7 +2,7 @@
 
 let
    useX11 = stdenv.isi686 || stdenv.isx86_64;
-   inherit (stdenv.lib) optionals optionalString;
+   inherit (stdenv.lib) optionals;
 in
 
 stdenv.mkDerivation rec {
diff --git a/pkgs/development/compilers/rust/binaryBuild.nix b/pkgs/development/compilers/rust/binaryBuild.nix
index 4c3c5d008f06..dbfc14e30efa 100644
--- a/pkgs/development/compilers/rust/binaryBuild.nix
+++ b/pkgs/development/compilers/rust/binaryBuild.nix
@@ -6,8 +6,7 @@
 }:
 
 let
-  inherit (stdenv.lib) getLib optionalString;
-  inherit (darwin) libiconv;
+  inherit (stdenv.lib) optionalString;
   inherit (darwin.apple_sdk.frameworks) Security;
 
   bootstrapping = versionType == "bootstrap";
diff --git a/pkgs/development/haskell-modules/default.nix b/pkgs/development/haskell-modules/default.nix
index 7b512e46da80..b8943a55394a 100644
--- a/pkgs/development/haskell-modules/default.nix
+++ b/pkgs/development/haskell-modules/default.nix
@@ -11,7 +11,7 @@
 let
 
   inherit (lib) extends makeExtensible;
-  inherit (haskellLib) overrideCabal makePackageSet;
+  inherit (haskellLib) makePackageSet;
 
   haskellPackages = pkgs.callPackage makePackageSet {
     package-set = initialPackages;
diff --git a/pkgs/development/haskell-modules/hoogle.nix b/pkgs/development/haskell-modules/hoogle.nix
index 7b3fe8fba023..c7fbab6ab88c 100644
--- a/pkgs/development/haskell-modules/hoogle.nix
+++ b/pkgs/development/haskell-modules/hoogle.nix
@@ -28,7 +28,6 @@
 }:
 
 let
-  inherit (stdenv.lib) optional;
   wrapper = ./hoogle-local-wrapper.sh;
   isGhcjs = ghc.isGhcjs or false;
   opts = lib.optionalString;
diff --git a/pkgs/development/libraries/blitz/default.nix b/pkgs/development/libraries/blitz/default.nix
index 5ae9ead9ced4..503e4b0fa43b 100644
--- a/pkgs/development/libraries/blitz/default.nix
+++ b/pkgs/development/libraries/blitz/default.nix
@@ -19,7 +19,7 @@
 assert enableSerialization -> boost != null;
 
 let
-  inherit (stdenv.lib) optional optionals optionalString;
+  inherit (stdenv.lib) optional optionals;
 in
 
 stdenv.mkDerivation rec {
diff --git a/pkgs/development/libraries/ffmpeg/generic.nix b/pkgs/development/libraries/ffmpeg/generic.nix
index 3d9027db1602..e763e5c1159c 100644
--- a/pkgs/development/libraries/ffmpeg/generic.nix
+++ b/pkgs/development/libraries/ffmpeg/generic.nix
@@ -42,7 +42,7 @@
  */
 
 let
-  inherit (stdenv) icCygwin isDarwin isFreeBSD isLinux isAarch32;
+  inherit (stdenv) isDarwin isFreeBSD isLinux isAarch32;
   inherit (stdenv.lib) optional optionals enableFeature;
 
   cmpVer = builtins.compareVersions;
diff --git a/pkgs/development/libraries/freetype/default.nix b/pkgs/development/libraries/freetype/default.nix
index 23aa86af377c..dbfb18a22ed6 100644
--- a/pkgs/development/libraries/freetype/default.nix
+++ b/pkgs/development/libraries/freetype/default.nix
@@ -10,7 +10,7 @@
 }:
 
 let
-  inherit (stdenv.lib) optional optionals optionalString;
+  inherit (stdenv.lib) optional optionalString;
 
 in stdenv.mkDerivation rec {
   name = "freetype-${version}";
diff --git a/pkgs/development/libraries/gstreamer/good/default.nix b/pkgs/development/libraries/gstreamer/good/default.nix
index 11e0894df3c3..ad7309be0445 100644
--- a/pkgs/development/libraries/gstreamer/good/default.nix
+++ b/pkgs/development/libraries/gstreamer/good/default.nix
@@ -12,7 +12,7 @@
 assert gtkSupport -> gtk3 != null;
 
 let
-  inherit (stdenv.lib) optional optionals optionalString;
+  inherit (stdenv.lib) optional optionals;
 in
 stdenv.mkDerivation rec {
   name = "gst-plugins-good-1.14.0";
diff --git a/pkgs/development/libraries/libav/default.nix b/pkgs/development/libraries/libav/default.nix
index dfe1455759a6..5eb90aaf05c9 100644
--- a/pkgs/development/libraries/libav/default.nix
+++ b/pkgs/development/libraries/libav/default.nix
@@ -18,7 +18,7 @@
 
 assert faacSupport -> enableUnfree;
 
-let inherit (stdenv.lib) optional optionals hasPrefix enableFeature; in
+let inherit (stdenv.lib) optional hasPrefix enableFeature; in
 
 /* ToDo:
     - more deps, inspiration: https://packages.ubuntu.com/raring/libav-tools
diff --git a/pkgs/development/libraries/libgsf/default.nix b/pkgs/development/libraries/libgsf/default.nix
index b0013d0f9491..90daf2ddf743 100644
--- a/pkgs/development/libraries/libgsf/default.nix
+++ b/pkgs/development/libraries/libgsf/default.nix
@@ -1,8 +1,6 @@
 { fetchurl, stdenv, pkgconfig, intltool, gettext, glib, libxml2, zlib, bzip2
 , python, perl, gdk_pixbuf, libiconv, libintl }:
 
-let inherit (stdenv.lib) optionals; in
-
 stdenv.mkDerivation rec {
   name = "libgsf-1.14.42";
 
diff --git a/pkgs/development/libraries/libvpx/default.nix b/pkgs/development/libraries/libvpx/default.nix
index 731892d33b4d..7e3780603f7c 100644
--- a/pkgs/development/libraries/libvpx/default.nix
+++ b/pkgs/development/libraries/libvpx/default.nix
@@ -41,7 +41,7 @@
 }:
 
 let
-  inherit (stdenv) isi686 isx86_64 isAarch32 is64bit isMips isDarwin isCygwin;
+  inherit (stdenv) is64bit isMips isDarwin isCygwin;
   inherit (stdenv.lib) enableFeature optional optionals;
 in
 
diff --git a/pkgs/development/libraries/opendbx/default.nix b/pkgs/development/libraries/opendbx/default.nix
index 20a62ef67f98..a073a29b507d 100644
--- a/pkgs/development/libraries/opendbx/default.nix
+++ b/pkgs/development/libraries/opendbx/default.nix
@@ -1,8 +1,5 @@
 { stdenv, fetchurl, readline, mysql, postgresql, sqlite }:
 
-let
-  inherit (stdenv.lib) getDev getLib;
-in
 stdenv.mkDerivation rec {
   name = "opendbx-1.4.6";
 
diff --git a/pkgs/development/libraries/science/math/liblapack/default.nix b/pkgs/development/libraries/science/math/liblapack/default.nix
index c68454fbe4a1..e6af2251b1f1 100644
--- a/pkgs/development/libraries/science/math/liblapack/default.nix
+++ b/pkgs/development/libraries/science/math/liblapack/default.nix
@@ -11,8 +11,7 @@ let
   atlasMaybeShared = if atlas != null then atlas.override { inherit shared; }
                      else null;
   usedLibExtension = if shared then ".so" else ".a";
-  inherit (stdenv.lib) optional optionals concatStringsSep;
-  inherit (builtins) hasAttr attrNames;
+  inherit (stdenv.lib) optional optionals;
   version = "3.8.0";
 in
 
diff --git a/pkgs/development/python-modules/pandas/0.17.1.nix b/pkgs/development/python-modules/pandas/0.17.1.nix
index 2c0a2c44f6eb..cab93429b57c 100644
--- a/pkgs/development/python-modules/pandas/0.17.1.nix
+++ b/pkgs/development/python-modules/pandas/0.17.1.nix
@@ -23,7 +23,7 @@
 }:
 
 let
-  inherit (stdenv.lib) optional optionalString concatStringsSep;
+  inherit (stdenv.lib) optional optionalString;
   inherit (stdenv) isDarwin;
 in buildPythonPackage rec {
   pname = "pandas";
diff --git a/pkgs/development/python-modules/pandas/default.nix b/pkgs/development/python-modules/pandas/default.nix
index 08fdddb73467..03be247ab475 100644
--- a/pkgs/development/python-modules/pandas/default.nix
+++ b/pkgs/development/python-modules/pandas/default.nix
@@ -24,7 +24,7 @@
 }:
 
 let
-  inherit (stdenv.lib) optional optionals optionalString concatStringsSep;
+  inherit (stdenv.lib) optional optionals optionalString;
   inherit (stdenv) isDarwin;
 
 in buildPythonPackage rec {
diff --git a/pkgs/development/tools/misc/binutils/default.nix b/pkgs/development/tools/misc/binutils/default.nix
index 0b71c6719dc4..be5dfa945c0d 100644
--- a/pkgs/development/tools/misc/binutils/default.nix
+++ b/pkgs/development/tools/misc/binutils/default.nix
@@ -10,7 +10,7 @@ let
   # https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff;h=330b90b5ffbbc20c5de6ae6c7f60c40fab2e7a4f;hp=99181ccac0fc7d82e7dabb05dc7466e91f1645d3
   version = "2.30";
   basename = "binutils-${version}";
-  inherit (stdenv.lib) optional optionals optionalString;
+  inherit (stdenv.lib) optionals optionalString;
   # The targetPrefix prepended to binary names to allow multiple binuntils on the
   # PATH to both be usable.
   targetPrefix = optionalString (targetPlatform != hostPlatform) "${targetPlatform.config}-";
diff --git a/pkgs/development/tools/misc/gdbgui/requirements.nix b/pkgs/development/tools/misc/gdbgui/requirements.nix
index 13978645c299..273f9db0c399 100644
--- a/pkgs/development/tools/misc/gdbgui/requirements.nix
+++ b/pkgs/development/tools/misc/gdbgui/requirements.nix
@@ -11,7 +11,7 @@
 let
 
   inherit (pkgs) makeWrapper;
-  inherit (pkgs.stdenv.lib) fix' extends inNixShell;
+  inherit (pkgs.stdenv.lib) fix' extends;
 
   pythonPackages =
   import "${toString pkgs.path}/pkgs/top-level/python-packages.nix" {
diff --git a/pkgs/development/tools/xcbuild/wrapper.nix b/pkgs/development/tools/xcbuild/wrapper.nix
index f8b1c1bf31e9..8f71e995183e 100644
--- a/pkgs/development/tools/xcbuild/wrapper.nix
+++ b/pkgs/development/tools/xcbuild/wrapper.nix
@@ -7,8 +7,6 @@
 
 let
 
-  inherit (lib) toLower;
-
   toolchainName = "com.apple.dt.toolchain.XcodeDefault";
   sdkName = "${xcodePlatform}${sdkVer}";
 
diff --git a/pkgs/misc/vim-plugins/default.nix b/pkgs/misc/vim-plugins/default.nix
index 8428a3b7894a..3e662d33f422 100644
--- a/pkgs/misc/vim-plugins/default.nix
+++ b/pkgs/misc/vim-plugins/default.nix
@@ -14,8 +14,7 @@ let
 
   _skim = skim;
 
-  inherit (vimUtils.override {inherit vim;}) rtpPath addRtp buildVimPlugin
-    buildVimPluginFrom2Nix vimHelpTags;
+  inherit (vimUtils.override {inherit vim;}) buildVimPluginFrom2Nix;
 
 
 # TL;DR
diff --git a/pkgs/misc/vscode-extensions/default.nix b/pkgs/misc/vscode-extensions/default.nix
index 16ddb8fd4052..6b431456b355 100644
--- a/pkgs/misc/vscode-extensions/default.nix
+++ b/pkgs/misc/vscode-extensions/default.nix
@@ -1,8 +1,7 @@
 { stdenv, lib, fetchurl, callPackage, vscode-utils }:
 
 let
-  inherit (vscode-utils) buildVscodeExtension buildVscodeMarketplaceExtension
-      extensionFromVscodeMarketplace;
+  inherit (vscode-utils) buildVscodeMarketplaceExtension;
 in
 #
 # Unless there is a good reason not to, we attemp to use the same name as the 
diff --git a/pkgs/servers/coturn/default.nix b/pkgs/servers/coturn/default.nix
index f83ef4cef388..0891b72cd1e9 100644
--- a/pkgs/servers/coturn/default.nix
+++ b/pkgs/servers/coturn/default.nix
@@ -1,7 +1,5 @@
 { stdenv, fetchFromGitHub, openssl, libevent }:
 
-let inherit (stdenv.lib) optional; in
-
 stdenv.mkDerivation rec {
   name = "coturn-${version}";
   version = "4.5.0.7";
diff --git a/pkgs/servers/dns/knot-resolver/default.nix b/pkgs/servers/dns/knot-resolver/default.nix
index bfa610b57d8a..b9c2faeae6e2 100644
--- a/pkgs/servers/dns/knot-resolver/default.nix
+++ b/pkgs/servers/dns/knot-resolver/default.nix
@@ -8,7 +8,7 @@ let # un-indented, over the whole file
 
 result = if extraFeatures then wrapped-full else unwrapped;
 
-inherit (stdenv.lib) optional optionals optionalString concatStringsSep;
+inherit (stdenv.lib) optional concatStringsSep;
 
 unwrapped = stdenv.mkDerivation rec {
   name = "knot-resolver-${version}";
diff --git a/pkgs/stdenv/native/default.nix b/pkgs/stdenv/native/default.nix
index 78f7a82d2952..37795b11f6dd 100644
--- a/pkgs/stdenv/native/default.nix
+++ b/pkgs/stdenv/native/default.nix
@@ -5,7 +5,7 @@
 assert crossSystem == null;
 
 let
-  inherit (localSystem) system platform;
+  inherit (localSystem) system;
 
   shell =
     if system == "i686-freebsd" || system == "x86_64-freebsd" then "/usr/local/bin/bash"
diff --git a/pkgs/tools/X11/xpra/default.nix b/pkgs/tools/X11/xpra/default.nix
index 8bff5a2e714a..9bc2a978e0e5 100644
--- a/pkgs/tools/X11/xpra/default.nix
+++ b/pkgs/tools/X11/xpra/default.nix
@@ -9,7 +9,7 @@
 with lib;
 
 let
-  inherit (python2Packages) python cython buildPythonApplication;
+  inherit (python2Packages) cython buildPythonApplication;
 in buildPythonApplication rec {
   name = "xpra-${version}";
   version = "2.3.2";
diff --git a/pkgs/tools/filesystems/sshfs-fuse/default.nix b/pkgs/tools/filesystems/sshfs-fuse/default.nix
index e9325e9b18d5..6d95d5ee12b5 100644
--- a/pkgs/tools/filesystems/sshfs-fuse/default.nix
+++ b/pkgs/tools/filesystems/sshfs-fuse/default.nix
@@ -2,9 +2,7 @@
 , docutils
 }:
 
-let
-  inherit (stdenv.lib) optional;
-in stdenv.mkDerivation rec {
+stdenv.mkDerivation rec {
   version = "3.4.0";
   name = "sshfs-fuse-${version}";
 
diff --git a/pkgs/tools/graphics/graphviz/base.nix b/pkgs/tools/graphics/graphviz/base.nix
index 2fa4bb90a8ea..68ff84c7495a 100644
--- a/pkgs/tools/graphics/graphviz/base.nix
+++ b/pkgs/tools/graphics/graphviz/base.nix
@@ -7,7 +7,7 @@
 assert stdenv.isDarwin -> ApplicationServices != null;
 
 let
-  inherit (stdenv.lib) optional optionals optionalString;
+  inherit (stdenv.lib) optionals optionalString;
 in
 
 stdenv.mkDerivation rec {
diff --git a/pkgs/tools/misc/findutils/default.nix b/pkgs/tools/misc/findutils/default.nix
index f79720289bf5..66b7ef4c2919 100644
--- a/pkgs/tools/misc/findutils/default.nix
+++ b/pkgs/tools/misc/findutils/default.nix
@@ -3,8 +3,6 @@
 , buildPlatform, hostPlatform
 }:
 
-let inherit (stdenv.lib) optionals; in
-
 stdenv.mkDerivation rec {
   name = "findutils-4.6.0";
 
diff --git a/pkgs/tools/networking/spoofer/default.nix b/pkgs/tools/networking/spoofer/default.nix
index 675777e4faa6..acda30dbfef8 100644
--- a/pkgs/tools/networking/spoofer/default.nix
+++ b/pkgs/tools/networking/spoofer/default.nix
@@ -1,7 +1,7 @@
 { stdenv, fetchurl, pkgconfig, protobuf, openssl, libpcap, traceroute
 , withGUI ? false, qt5 }:
 
-let inherit (stdenv.lib) optional optionalString;
+let inherit (stdenv.lib) optional;
 in
 
 stdenv.mkDerivation rec {
diff --git a/pkgs/tools/system/ddrescue/default.nix b/pkgs/tools/system/ddrescue/default.nix
index fc42c3b856f6..91489388eec6 100644
--- a/pkgs/tools/system/ddrescue/default.nix
+++ b/pkgs/tools/system/ddrescue/default.nix
@@ -3,8 +3,6 @@
 , hostPlatform, buildPlatform
 }:
 
-let inherit (stdenv.lib) optionals; in
-
 stdenv.mkDerivation rec {
   name = "ddrescue-1.23";