1 files changed, 12 insertions, 11 deletions

diff --git a/events/src/Events/Spec/Eval.hs b/events/src/Events/Spec/Eval.hs
index 24cfeb6..ddb32e4 100644
--- a/events/src/Events/Spec/Eval.hs
+++ b/events/src/Events/Spec/Eval.hs
@@ -49,21 +49,22 @@ evalExpr (EApp f a)               = evalExpr $ beta a (evalExpr f)
 -- bindE :: (m a -> b) -> Expr m (a ': Ctx b) (Fin b)
 -- bindE f = liftE $ bindE . f
 
-type family Ctx f where
-  Ctx (a -> b) = (a ': Ctx b)
-  Ctx a = '[]
+type family Ctx m f where
+  Ctx m (m a -> b) = (a ': Ctx m b)
+  Ctx m a = '[]
 
-type family Fin f where
-  Fin (a -> b) = Fin b
-  Fin a = a
+type family Fin m f where
+  Fin m (m a -> b) = Fin m b
+  Fin m (m a) = a
+  Fin m a = a
 
 class Bindable m b where
-  bindE :: (Val m a -> m b) -> Expr m (a ': Ctx b) (Fin b)
+  bindE :: (Val m a -> b) -> Expr m (a ': Ctx m b) (Fin m b)
 
-instance {-# OVERLAPS #-} ((Val m b) ~ (m b), Applicative m, Bindable m c) => Bindable m (b -> c) where
-  bindE :: (Val m a -> m (b -> c)) -> Expr m (a ': b ': Ctx c) (Fin c)
-  bindE f = (EPri :: (Val m a -> Expr m (b ': Ctx c) (Fin c)) -> Expr m (a ': b ': Ctx c) (Fin c)) . ((bindE :: (Val m b -> m c) -> Expr m (b ': Ctx c) (Fin c)) . ) $ ((<*>) . f)
+instance ((Val m b) ~ (m b), Applicative m, Bindable m c) => Bindable m (m b -> c) where
+  bindE :: (Val m a -> m b -> c) -> Expr m (a ': b ': Ctx m c) (Fin m c)
+  bindE f = (EPri :: (Val m a -> Expr m (b ': Ctx m c) (Fin m c)) -> Expr m (a ': b ': Ctx m c) (Fin m c)) . ((bindE :: (Val m b -> c) -> Expr m (b ': Ctx m c) (Fin m c)) . ) $ f
 
-instance (Val m b ~ m b, Ctx b ~ '[], Fin b ~ b) => Bindable m b where
+instance {-# OVERLAPPABLE #-} (Val m b ~ m b, Ctx m (m b) ~ '[], Fin m (m b) ~ b) => Bindable m (m b) where
   bindE :: (Val m a -> Val m b) -> Expr m '[a] b
   bindE = EPri . (EVal .)