diff --git a/pkgs/development/haskell-modules/generic-builder.nix b/pkgs/development/haskell-modules/generic-builder.nix
index a9c8f11223f7..b91da1669527 100644
--- a/pkgs/development/haskell-modules/generic-builder.nix
+++ b/pkgs/development/haskell-modules/generic-builder.nix
@@ -481,7 +481,7 @@ stdenv.mkDerivation ({
       # ^^ if the project is not a library, and we have a build target, then use "copy" to install
       # just the target specified; "install" will error here, since not all targets have been built.
     else ''
-      ${setupCommand} copy
+      ${setupCommand} copy ${buildTarget}
       local packageConfDir="$out/lib/${ghc.name}/package.conf.d"
       local packageConfFile="$packageConfDir/${pname}-${version}.conf"
       mkdir -p "$packageConfDir"