diff --git a/pkgs/applications/audio/zynaddsubfx/default.nix b/pkgs/applications/audio/zynaddsubfx/default.nix
index da5abd1baccb..9cde53585717 100644
--- a/pkgs/applications/audio/zynaddsubfx/default.nix
+++ b/pkgs/applications/audio/zynaddsubfx/default.nix
@@ -48,7 +48,7 @@
   ctestCheckHook,
 }:
 
-assert builtins.any (g: guiModule == g) [
+assert builtins.elem guiModule [
   "fltk"
   "ntk"
   "zest"