1 files changed, 5 insertions, 5 deletions
diff --git a/pkgs/development/libraries/wxGTK/default.nix b/pkgs/development/libraries/wxGTK/default.nix
index 0645de6495d7..039579c2d543 100644
--- a/pkgs/development/libraries/wxGTK/default.nix
+++ b/pkgs/development/libraries/wxGTK/default.nix
@@ -1,10 +1,10 @@
 {stdenv, fetchurl, pkgconfig, gtk, compat22 ? true}:
 
-assert !isNull pkgconfig && !isNull gtk;
-assert !isNull gtk.libtiff;
-assert !isNull gtk.libjpeg;
-assert !isNull gtk.libpng;
-assert !isNull gtk.libpng.zlib;
+assert pkgconfig != null && gtk != null;
+assert gtk.libtiff != null;
+assert gtk.libjpeg != null;
+assert gtk.libpng != null;
+assert gtk.libpng.zlib != null;
 
 derivation {
   name = "wxGTK-2.4.2";