diff --git a/pkgs/by-name/wk/wkhtmltopdf/package.nix b/pkgs/by-name/wk/wkhtmltopdf/package.nix
index 67c5d26ef8ef..24ecddd3dc9a 100644
--- a/pkgs/by-name/wk/wkhtmltopdf/package.nix
+++ b/pkgs/by-name/wk/wkhtmltopdf/package.nix
@@ -124,5 +124,7 @@ stdenv.mkDerivation (
     };
   }
   // lib.optionalAttrs (stdenv.hostPlatform.isDarwin) darwinAttrs
-  // lib.optionalAttrs (stdenv.hostPlatform.isLinux) linuxAttrs.${stdenv.system}
+  //
+    lib.optionalAttrs (stdenv.hostPlatform.isLinux)
+      linuxAttrs.${stdenv.system} or (throw "Unsupported system: ${stdenv.system}")
 )