diff --git a/pkgs/applications/blockchains/ledger-live-desktop/default.nix b/pkgs/applications/blockchains/ledger-live-desktop/default.nix
index d130b3d04541..3d72a91551f2 100644
--- a/pkgs/applications/blockchains/ledger-live-desktop/default.nix
+++ b/pkgs/applications/blockchains/ledger-live-desktop/default.nix
@@ -1,4 +1,4 @@
-{ lib, fetchurl, makeDesktopItem, appimageTools, imagemagick }:
+{ lib, fetchurl, appimageTools, imagemagick }:
 
 let
   pname = "ledger-live-desktop";
diff --git a/pkgs/applications/editors/standardnotes/default.nix b/pkgs/applications/editors/standardnotes/default.nix
index e66febbf7fc2..0d50c24d3976 100644
--- a/pkgs/applications/editors/standardnotes/default.nix
+++ b/pkgs/applications/editors/standardnotes/default.nix
@@ -1,5 +1,5 @@
 { lib, stdenv, appimageTools, autoPatchelfHook, desktop-file-utils
-, fetchurl, runtimeShell, libsecret, gtk3, gsettings-desktop-schemas }:
+, fetchurl, libsecret, gtk3, gsettings-desktop-schemas }:
 
 let
   version = "3.5.18";
diff --git a/pkgs/applications/misc/clipit/default.nix b/pkgs/applications/misc/clipit/default.nix
index 630ee3c36830..fafcf3d54404 100644
--- a/pkgs/applications/misc/clipit/default.nix
+++ b/pkgs/applications/misc/clipit/default.nix
@@ -1,4 +1,4 @@
-{ fetchFromGitHub, fetchpatch, lib, stdenv
+{ fetchFromGitHub, lib, stdenv
 , autoreconfHook, intltool, pkg-config
 , gtk3, libayatana-appindicator, xdotool, which, wrapGAppsHook }:
 
diff --git a/pkgs/applications/misc/megasync/default.nix b/pkgs/applications/misc/megasync/default.nix
index c302a4b4a074..1c87747eaca1 100644
--- a/pkgs/applications/misc/megasync/default.nix
+++ b/pkgs/applications/misc/megasync/default.nix
@@ -6,7 +6,6 @@
 , curl
 , doxygen
 , fetchFromGitHub
-, fetchpatch
 , ffmpeg_3
 , libmediainfo
 , libraw
diff --git a/pkgs/applications/networking/instant-messengers/ripcord/default.nix b/pkgs/applications/networking/instant-messengers/ripcord/default.nix
index e5221d861d36..6d6e70ff26a0 100755
--- a/pkgs/applications/networking/instant-messengers/ripcord/default.nix
+++ b/pkgs/applications/networking/instant-messengers/ripcord/default.nix
@@ -1,7 +1,7 @@
-{ lib, mkDerivation, fetchurl, makeFontsConf, appimageTools,
-  qtbase, qtsvg, qtmultimedia, qtwebsockets, qtimageformats,
-  autoPatchelfHook, desktop-file-utils, imagemagick, makeWrapper,
-  twemoji-color-font, xorg, libsodium, libopus, libGL, zlib, alsaLib }:
+{ lib, mkDerivation, fetchurl, makeFontsConf, appimageTools
+, qtbase, qtsvg, qtmultimedia, qtwebsockets, qtimageformats
+, autoPatchelfHook, desktop-file-utils, imagemagick
+, twemoji-color-font, xorg, libsodium, libopus, libGL, alsaLib }:
 
 mkDerivation rec {
   pname = "ripcord";
@@ -19,9 +19,9 @@ mkDerivation rec {
   };
 
   nativeBuildInputs = [ autoPatchelfHook desktop-file-utils imagemagick ];
-  buildInputs = [ libsodium libopus libGL alsaLib ] ++
-                [ qtbase qtsvg qtmultimedia qtwebsockets qtimageformats ] ++
-                (with xorg; [ libX11 libXScrnSaver libXcursor xkeyboardconfig ]);
+  buildInputs = [ libsodium libopus libGL alsaLib ]
+    ++ [ qtbase qtsvg qtmultimedia qtwebsockets qtimageformats ]
+    ++ (with xorg; [ libX11 libXScrnSaver libXcursor xkeyboardconfig ]);
 
   fontsConf = makeFontsConf {
     fontDirectories = [ twemoji-color-font ];
@@ -60,10 +60,8 @@ mkDerivation rec {
   meta = with lib; {
     description = "Desktop chat client for Slack and Discord";
     homepage = "https://cancel.fm/ripcord/";
-
     # See: https://cancel.fm/ripcord/shareware-redistribution/
     license = licenses.unfreeRedistributable;
-
     maintainers = with maintainers; [ infinisil ];
     platforms = [ "x86_64-linux" ];
   };
diff --git a/pkgs/applications/networking/modem-manager-gui/default.nix b/pkgs/applications/networking/modem-manager-gui/default.nix
index da36589aeecb..2723f3420436 100644
--- a/pkgs/applications/networking/modem-manager-gui/default.nix
+++ b/pkgs/applications/networking/modem-manager-gui/default.nix
@@ -10,7 +10,6 @@
 , itstool
 , libayatana-appindicator-gtk3
 , perlPackages
-, glibcLocales
 , meson
 , ninja
 }:
diff --git a/pkgs/applications/office/timeular/default.nix b/pkgs/applications/office/timeular/default.nix
index 6c1068d45844..5bbfca23d6de 100644
--- a/pkgs/applications/office/timeular/default.nix
+++ b/pkgs/applications/office/timeular/default.nix
@@ -1,8 +1,7 @@
-{
-  lib,
-  fetchurl,
-  appimageTools,
-  libsecret
+{ lib
+, fetchurl
+, appimageTools
+, libsecret
 }:
 
 let
@@ -37,7 +36,7 @@ in appimageTools.wrapType2 rec {
       Assign an activity to each side and flip to start tracking your time.
       The desktop app tell you where every minute of your day is spent.
     '';
-    homepage = https://timeular.com;
+    homepage = "https://timeular.com";
     license = licenses.unfree;
     maintainers = with maintainers; [ ktor ];
     platforms = [ "x86_64-linux" ];
diff --git a/pkgs/applications/virtualization/qemu/default.nix b/pkgs/applications/virtualization/qemu/default.nix
index dd1a2da01711..b4b16e216893 100644
--- a/pkgs/applications/virtualization/qemu/default.nix
+++ b/pkgs/applications/virtualization/qemu/default.nix
@@ -147,7 +147,7 @@ stdenv.mkDerivation rec {
 
   postFixup = ''
     # the .desktop is both invalid and pointless
-    test -e $out/share/applications/qemu.desktop && rm -f $out/share/applications/qemu.desktop
+    rm -f $out/share/applications/qemu.desktop
 
     # copy qemu-ga (guest agent) to separate output
     mkdir -p $ga/bin
diff --git a/pkgs/applications/virtualization/singularity/default.nix b/pkgs/applications/virtualization/singularity/default.nix
index 3bc2df19d1de..a51a58d21eeb 100644
--- a/pkgs/applications/virtualization/singularity/default.nix
+++ b/pkgs/applications/virtualization/singularity/default.nix
@@ -5,7 +5,6 @@
 , openssl
 , libuuid
 , coreutils
-, go
 , which
 , makeWrapper
 , cryptsetup
diff --git a/pkgs/desktops/pantheon/desktop/elementary-session-settings/default.nix b/pkgs/desktops/pantheon/desktop/elementary-session-settings/default.nix
index e45d25cfa342..38fcb8d40b41 100644
--- a/pkgs/desktops/pantheon/desktop/elementary-session-settings/default.nix
+++ b/pkgs/desktops/pantheon/desktop/elementary-session-settings/default.nix
@@ -1,7 +1,6 @@
 { lib, stdenv
 , fetchFromGitHub
 , nix-update-script
-, substituteAll
 , desktop-file-utils
 , pkg-config
 , writeScript
diff --git a/pkgs/desktops/xfce/applications/xfce4-taskmanager/default.nix b/pkgs/desktops/xfce/applications/xfce4-taskmanager/default.nix
index 9a923025c94d..fd59b173a732 100644
--- a/pkgs/desktops/xfce/applications/xfce4-taskmanager/default.nix
+++ b/pkgs/desktops/xfce/applications/xfce4-taskmanager/default.nix
@@ -1,4 +1,4 @@
-{ lib, mkXfceDerivation, exo, gtk3, libwnck3, libXmu }:
+{ mkXfceDerivation, exo, gtk3, libwnck3, libXmu }:
 
 mkXfceDerivation {
   category = "apps";
diff --git a/pkgs/development/libraries/crypto++/default.nix b/pkgs/development/libraries/crypto++/default.nix
index 6c4a3bfc0840..fe553cb37b9e 100644
--- a/pkgs/development/libraries/crypto++/default.nix
+++ b/pkgs/development/libraries/crypto++/default.nix
@@ -1,4 +1,4 @@
-{ lib, stdenv, fetchFromGitHub, nasm, which
+{ lib, stdenv, fetchFromGitHub
 , enableStatic ? stdenv.hostPlatform.isStatic
 , enableShared ? !enableStatic
 }:
diff --git a/pkgs/development/libraries/libayatana-appindicator/default.nix b/pkgs/development/libraries/libayatana-appindicator/default.nix
index ef9823130f43..186e8c42f4ba 100644
--- a/pkgs/development/libraries/libayatana-appindicator/default.nix
+++ b/pkgs/development/libraries/libayatana-appindicator/default.nix
@@ -18,11 +18,6 @@ stdenv.mkDerivation rec {
     sha256 = "1sba0w455rdkadkhxrx4fr63m0d9blsbb1q1hcshxw1k1z2nh1gk";
   };
 
-  prePatch = ''
-    substituteInPlace configure.ac \
-      --replace "codegendir pygtk-2.0" "codegendir pygobject-2.0"
-  '';
-
   nativeBuildInputs = [ pkg-config autoreconfHook gtk-doc gobject-introspection python2 python2Packages.pygtk dbus-glib ];
 
   buildInputs =
diff --git a/pkgs/development/python-modules/gviz-api/default.nix b/pkgs/development/python-modules/gviz-api/default.nix
index fabc2d147fca..92f33abb594a 100644
--- a/pkgs/development/python-modules/gviz-api/default.nix
+++ b/pkgs/development/python-modules/gviz-api/default.nix
@@ -8,8 +8,7 @@ buildPythonPackage rec {
   format = "wheel";
 
   src = fetchPypi {
-    inherit pname version;
-    format = "wheel";
+    inherit pname version format;
     sha256 = "1yag559lpmwfdxpxn679a6ajifcbpgljr5n6k5b7rrj38k2xq7jg";
   };
 
diff --git a/pkgs/development/python-modules/httpbin/default.nix b/pkgs/development/python-modules/httpbin/default.nix
index 2e711141fcba..ace9a7041e3f 100644
--- a/pkgs/development/python-modules/httpbin/default.nix
+++ b/pkgs/development/python-modules/httpbin/default.nix
@@ -1,7 +1,6 @@
 { lib
 , buildPythonPackage
 , fetchPypi
-, fetchpatch
 , flask
 , flask-limiter
 , markupsafe
diff --git a/pkgs/development/python-modules/johnnycanencrypt/default.nix b/pkgs/development/python-modules/johnnycanencrypt/default.nix
index a0c82902d3e6..460b0cddf616 100644
--- a/pkgs/development/python-modules/johnnycanencrypt/default.nix
+++ b/pkgs/development/python-modules/johnnycanencrypt/default.nix
@@ -5,7 +5,6 @@
 , rustPlatform
 , llvmPackages
 , pkg-config
-, maturin
 , pcsclite
 , nettle
 , requests
diff --git a/pkgs/development/python-modules/jq/default.nix b/pkgs/development/python-modules/jq/default.nix
index 3d4097b07186..271f15c59000 100644
--- a/pkgs/development/python-modules/jq/default.nix
+++ b/pkgs/development/python-modules/jq/default.nix
@@ -8,10 +8,15 @@ buildPythonPackage rec {
     inherit pname version;
     sha256 = "62d649c4f6f26ed91810c8db075f5fe05319c3dc99dbebcd2d31b0b697a4592e";
   };
+
   patches = [ ./jq-py-setup.patch ];
 
   buildInputs = [ jq ];
 
+  # no tests executed
+  doCheck = false;
+  pythonImportsCheck = [ "jq" ];
+
   meta = {
     description = "Python bindings for jq, the flexible JSON processor";
     homepage = "https://github.com/mwilliamson/jq.py";
diff --git a/pkgs/development/python-modules/knack/default.nix b/pkgs/development/python-modules/knack/default.nix
index c08bdab4cf34..4bead9961988 100644
--- a/pkgs/development/python-modules/knack/default.nix
+++ b/pkgs/development/python-modules/knack/default.nix
@@ -4,7 +4,6 @@
 , argcomplete
 , colorama
 , jmespath
-, knack
 , pygments
 , pyyaml
 , six
diff --git a/pkgs/development/python-modules/papis/default.nix b/pkgs/development/python-modules/papis/default.nix
index b05a525d91ad..3e7c6ae00116 100644
--- a/pkgs/development/python-modules/papis/default.nix
+++ b/pkgs/development/python-modules/papis/default.nix
@@ -3,7 +3,7 @@
 , pyyaml, chardet, beautifulsoup4, colorama, bibtexparser
 , click, python-slugify, habanero, isbnlib, typing-extensions
 , prompt_toolkit, pygments, stevedore, tqdm, lxml
-, python-doi, isPy3k, pythonOlder, pytestcov
+, python-doi, isPy3k, pytestcov
 #, optional, dependencies
 , whoosh, pytest
 , stdenv
diff --git a/pkgs/development/python-modules/powerline/default.nix b/pkgs/development/python-modules/powerline/default.nix
index 1ad17d0459dd..63f5feada595 100644
--- a/pkgs/development/python-modules/powerline/default.nix
+++ b/pkgs/development/python-modules/powerline/default.nix
@@ -1,6 +1,5 @@
 { lib
 , fetchFromGitHub
-, python
 , buildPythonPackage
 , socat
 , psutil
diff --git a/pkgs/development/python-modules/pytest-vcr/default.nix b/pkgs/development/python-modules/pytest-vcr/default.nix
index 9373c597b367..119f3021b413 100644
--- a/pkgs/development/python-modules/pytest-vcr/default.nix
+++ b/pkgs/development/python-modules/pytest-vcr/default.nix
@@ -1,7 +1,6 @@
 { lib
 , buildPythonPackage
 , fetchFromGitHub
-, pytestCheckHook
 , pytest
 , vcrpy
 }:
diff --git a/pkgs/development/python-modules/requests/default.nix b/pkgs/development/python-modules/requests/default.nix
index 169583586a1c..20ba44ee2a86 100644
--- a/pkgs/development/python-modules/requests/default.nix
+++ b/pkgs/development/python-modules/requests/default.nix
@@ -8,6 +8,7 @@
 , pytest-xdist
 , pytestCheckHook
 , urllib3
+, isPy27
 }:
 
 buildPythonPackage rec {
@@ -55,5 +56,7 @@ buildPythonPackage rec {
     homepage = "http://docs.python-requests.org/en/latest/";
     license = licenses.asl20;
     maintainers = with maintainers; [ fab ];
+    # AttributeError: 'KeywordMapping' object has no attribute 'get'
+    broken = isPy27;
   };
 }
diff --git a/pkgs/tools/networking/p2p/amule/default.nix b/pkgs/tools/networking/p2p/amule/default.nix
index 4ab93b7574a7..075d60038d8e 100644
--- a/pkgs/tools/networking/p2p/amule/default.nix
+++ b/pkgs/tools/networking/p2p/amule/default.nix
@@ -2,11 +2,8 @@
 , enableDaemon ? false # build amule daemon
 , httpServer ? false # build web interface for the daemon
 , client ? false # build amule remote gui
-, fetchFromGitHub, fetchpatch, stdenv, lib, zlib, wxGTK, perl, cryptopp, libupnp, gettext, libpng ? null
-, autoreconfHook, pkg-config, makeWrapper, libX11 ? null }:
-
-assert httpServer -> libpng != null;
-assert client -> libX11 != null;
+, fetchFromGitHub, stdenv, lib, zlib, wxGTK, perl, cryptopp, libupnp, gettext, libpng
+, autoreconfHook, pkg-config, makeWrapper, libX11 }:
 
 stdenv.mkDerivation rec {
   pname = "amule";
@@ -78,5 +75,7 @@ stdenv.mkDerivation rec {
     license = licenses.gpl2Plus;
     maintainers = with maintainers; [ phreedom ];
     platforms = platforms.unix;
+    # Could not find crypto++ installation or sources.
+    broken = true;
   };
 }