EtaExpandStupid2.hs:16:8: error: [GHC-39999]
    • No instance for ‘Num c’ arising from a use of ‘MkD4’
      Possible fix:
        add (Num c) to the context of
          the type signature for:
            foo4 :: forall c. Int -> c -> D4 Float# Int c
    • In the expression: MkD4 (9.0# `timesFloat#` 17.0#)
      In an equation for ‘foo4’: foo4 = MkD4 (9.0# `timesFloat#` 17.0#)