
<interactive>:11:1:
    No instance for (Show a1) arising from a use of ‘print’
    Cannot resolve unknown runtime type ‘a1’
    Use :print or :force to determine these types
    Relevant bindings include it :: a1 (bound at <interactive>:11:1)
    Note: there are several potential instances:
      instance Show TyCon -- Defined in ‘Data.Typeable.Internal’
      instance Show TypeRep -- Defined in ‘Data.Typeable.Internal’
      instance Show a => Show (Maybe a) -- Defined in ‘GHC.Show’
      ...plus 30 others
    In a stmt of an interactive GHCi command: print it