This reverts commit 79b0d0e6
due to

  Compile failed (status 256) errors were:
  [1 of 2] Compiling A                ( A.hs, A.o )
  [2 of 2] Compiling Main             ( T4491.hs, T4491.o )
  T4491.hs:19:11:
    Illegal data constructor name: ‘%’
    When splicing a TH expression: (GHC.Real.%) 11 2
    In the splice: $(dataToExpQ (const Nothing) (5.5 :: Rational))
  *** unexpected failure for T4491(normal)

Therefore re-opening #10011