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)