diff --git a/src/System/Plugins/Env.hs b/src/System/Plugins/Env.hs
index 7911b35..64a840c 100644
--- a/src/System/Plugins/Env.hs
+++ b/src/System/Plugins/Env.hs
@@ -286,7 +286,7 @@ union ls ps' =
         let fm = emptyFM -- new FM for this package.conf
         in foldr (\p fm' -> if packageName_ p == "base" -- ghc doesn't supply a version with 'base'
                                                         -- for some reason.
-                            then addToFM fm' (packageName_ p) p
+                            then addToFM (addToFM fm' (packageName_ p) p) (packageName p) p
                             else addToFM fm' (packageName p) p) fm ps' : ls
 
 --