Comments and tidy-up

[ghc-hetmet.git] / compiler / types / FunDeps.lhs

diff --git a/compiler/types/FunDeps.lhs b/compiler/types/FunDeps.lhs
index 0d7eb24..5ece047 100644 (file)
--- a/compiler/types/FunDeps.lhs
+++ b/compiler/types/FunDeps.lhs
@@ -222,7 +222,11 @@ NOTA BENE:
 improve inst_env preds
   = [ eqn | group <- equivClassesByUniq (predTyUnique . fst) (filterEqPreds preds),
            eqn   <- checkGroup inst_env group ]
-  where filterEqPreds = filter (not . isEqPred . fst)
+  where 
+    filterEqPreds = filter (not . isEqPred . fst)
+       -- Equality predicates don't have uniques
+       -- In any case, improvement *generates*, rather than
+       -- *consumes*, equality constraints
 
 ----------
 checkGroup :: (Class -> [Instance])