Remove superfluous constraints in the derived instances

UnkindPartition · Mar 16, 2013 · 6be85d3 · 6be85d3
1 parent c9a92f0
commit 6be85d3
Showing 1 changed file with 3 additions and 4 deletions.
diff --git a/Data/Generics/Traversable/TH.hs b/Data/Generics/Traversable/TH.hs
@@ -86,12 +86,11 @@ deriveGTraversable name = do
           funD 'gtraverse [ clause [] (normalB $ gtraverseExpr typeName) [] ]
         ]
 
-    context = sequence $ gtraversableContext ++ userContext
+    context = sequence userContext
 
-    types = filter (/= appliedType) $ nub [ t | (_,_,ts) <- constructors, t <- ts ]
+    types = nub [ t | (_,_,ts) <- constructors, t <- ts ]
 
-    userContext = [ classP ctx [pure t] | t <- appliedType : types ]
-    gtraversableContext = [ classP ''GTraversable [varT ctx, pure t] | t <- types ]
+    userContext = [ classP ctx [pure t] | t <- types ]
 
   sequence [inst]