diff --git a/pkgs/development/haskell-modules/generic-builder.nix b/pkgs/development/haskell-modules/generic-builder.nix
index 14a8a628b58c..71b2d1288a01 100644
--- a/pkgs/development/haskell-modules/generic-builder.nix
+++ b/pkgs/development/haskell-modules/generic-builder.nix
@@ -191,7 +191,7 @@ assert allPkgconfigDepends != [] -> pkgconfig != null;
 stdenv.mkDerivation ({
   name = "${pname}-${version}";
 
-  outputs = if (args ? outputs) then args.outputs else ([ "out" ] ++ (optional enableSeparateDataOutput "data") ++ (optional enableSeparateDocOutput "doc"));
+  outputs = [ "out" ] ++ (optional enableSeparateDataOutput "data") ++ (optional enableSeparateDocOutput "doc");
   setOutputFlags = false;
 
   pos = builtins.unsafeGetAttrPos "pname" args;