[Haskell-cafe] Problem with existential type and instance.

28 Jul 2014

      Hi,

  For code like below, how to make it compilable?

data EventHandlers = forall m. MonadIO m => EventHandlers { onDeleteWindow
:: Maybe (m ()) }
instance Default EventHandlers where
  def = EventHandlers Nothing

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[Haskell-cafe] Problem with existential type and instance.

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