tcfail106.hs:11:10: error:
    • No instance for (S Int)
        arising from the superclasses of an instance declaration
    • In the instance declaration for ‘C Int’

tcfail106.hs:14:10: error:
    • No instance for (S Int)
        arising from the superclasses of an instance declaration
    • In the instance declaration for ‘D Int’