T9017.hs:8:7: error: • Couldn't match kind ‘k1’ with ‘*’ ‘k1’ is a rigid type variable bound by the type signature for: foo :: forall k k1 (a :: k -> k1 -> *) (b :: k) (m :: k -> k1). a b (m b) at T9017.hs:7:1-16 When matching types a1 :: * -> * -> * a :: k -> k1 -> * Expected type: a b (m b) Actual type: a1 a0 (m0 a0) • In the expression: arr return In an equation for ‘foo’: foo = arr return • Relevant bindings include foo :: a b (m b) (bound at T9017.hs:8:1)