diff --git a/pkgs/development/libraries/qt-5/modules/qtbase.nix b/pkgs/development/libraries/qt-5/modules/qtbase.nix
index db1367f6fba5..0102c2fd1b6f 100644
--- a/pkgs/development/libraries/qt-5/modules/qtbase.nix
+++ b/pkgs/development/libraries/qt-5/modules/qtbase.nix
@@ -14,7 +14,7 @@
 
   # optional dependencies
 , cups ? null, libmysqlclient ? null, postgresql ? null
-, withGtk3 ? false, dconf ? null, gtk3 ? null
+, withGtk3 ? false, dconf, gtk3
 
   # options
 , libGLSupported ? !stdenv.isDarwin
@@ -26,9 +26,6 @@
 , decryptSslTraffic ? false
 }:
 
-assert withGtk3 -> dconf != null;
-assert withGtk3 -> gtk3 != null;
-
 let
   compareVersion = v: builtins.compareVersions version v;
   qmakeCacheName = if compareVersion "5.12.4" < 0 then ".qmake.cache" else ".qmake.stash";