tcfail076.hs:18:
    Inferred type is less polymorphic than expected
	Quantified type variable `res' escapes
	It unifies with `res1', which is mentioned in the environment
	The following variables in the environment mention `res1'
	  cont :: a -> m res1
    Signature type:     forall res. (a1 -> m1 res) -> m1 res
    Type to generalise: (b -> m res1) -> m res1
    When checking an expression type signature
    In the first argument of `KContT', namely `(\ cont' -> cont a)'
    In the right-hand side of a lambda abstraction:
	KContT (\ cont' -> cont a)