Top level: Warning:
    Module ‘Data.OldTypeable’ is deprecated: Use Data.Typeable instead

<interactive>:10:36: Warning:
    In the use of type constructor or class ‘Typeable’
    (imported from Data.OldTypeable, but defined in Data.OldTypeable.Internal):
    Deprecated: "Use Data.Typeable.Internal instead"

<interactive>:14:10:
    Typeable instances can only be derived in Safe Haskell.
    Replace the following instance:
      instance [safe] Typeable G

<interactive>:22:22:
    No instance for (Typeable G) arising from a use of ‘cast’
    In the expression: (cast y) :: Maybe H
    In a pattern binding: (Just y_as_H) = (cast y) :: Maybe H

<interactive>:23:1: Not in scope: ‘y_as_H’