@@ -8,6 +8,7 @@ import Control.Applicative
88import Control.Arrow
99import Control.Monad.RWS
1010import Control.Monad.State
11+import qualified Data.Set as S
1112import Data.List
1213import Data.Maybe
1314import qualified Data.Map.Strict as M
@@ -19,7 +20,7 @@ ucheck :: [(UConstraint, FC)] -> TC ()
1920ucheck cs = acyclic rels (map fst (M.toList rels))
2021 where lhs (ULT l _) = l
2122 lhs (ULE l _) = l
22− cs' = nub cs
23+ cs' = S.toList (S.fromList cs)
2324 rels = mkRels cs' M.empty
2425
2526type Relations = M.Map UExp [(UConstraint, FC)]