@@ -157,7 +157,7 @@ prettySubstitution = A.toJSON . M.mapKeysMonotonic (TL.pack . show) . fmap rende
158-- | @older <> newer@
158-- | @older <> newer@
159instance Semigroup Substitution where
159instance Semigroup Substitution where
160− (Substitution x) <> y'@(Substitution y) = Substitution (y <> fmap (sub y') x)
160+ x'@(Substitution x) <> (Substitution y) = Substitution (fmap (sub x') y <> x)
162instance Monoid Substitution where
162instance Monoid Substitution where
163 mempty = Substitution mempty
163 mempty = Substitution mempty