tc125.hs:16:10: Warning:
    No explicit method or default declaration for ‛add’
    In the instance declaration for ‛Add Z a a’

tc125.hs:17:10: Warning:
    No explicit method or default declaration for ‛add’
    In the instance declaration for ‛Add (S a) b (S c)’

tc125.hs:21:10: Warning:
    No explicit method or default declaration for ‛mul’
    In the instance declaration for ‛Mul Z a Z’

tc125.hs:22:10: Warning:
    No explicit method or default declaration for ‛mul’
    In the instance declaration for ‛Mul (S a) b d’

tc125.hs:29:10: Warning:
    No explicit method or default declaration for ‛add’
    In the instance declaration for ‛Add (Q a b) (Q c d) (Q ad_bc bd)’