prop_typeOf_eval' :: Term -> Bool
prop_typeOf_eval' t = 
    case eval' t of
        Just t' -> typeOf t == typeOf t'
        Nothing -> True
        
-- | The resulting type of evaluating should be the same for both evaluators.
prop_typeOf_eval' :: Term -> Bool
prop_typeOf_eval' t = 
    case eval' t of
        Just t' -> typeOf t == typeOf t'
        Nothing -> True
        
-- | The resulting type of evaluating should be the same for both evaluators.
prop_typeOf_eval' t = 
    case eval' t of
        Just t' -> typeOf t == typeOf t'
        Nothing -> True
        
-- | The resulting type of evaluating should be the same for both evaluators.