tcfail102.hs:1:14: warning:
    -XDatatypeContexts is deprecated: It was widely considered a misfeature, and has been removed from the Haskell language.

tcfail102.hs:9:15: error:
    • Could not deduce (Integral (Ratio a)) arising from a use of ‘p’
      from the context: Integral a
        bound by the type signature for:
                   f :: forall a. Integral a => P (Ratio a) -> P (Ratio a)
        at tcfail102.hs:8:1-45
    • In the ‘p’ field of a record
      In the expression: x {p = p x}
      In an equation for ‘f’: f x = x {p = p x}