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])