T18891a.hs:8:4: error: [GHC-89498]
    • A newtype must not be a GADT
      MkN1 :: N1 @GHC.Types.LiftedRep -> N1 @GHC.Types.LiftedRep
    • In the definition of data constructor ‘MkN1’
      In the newtype declaration for ‘N1’

T18891a.hs:12:3: error: [GHC-89498]
    • A newtype must not be a GADT
      MkN2 :: N2 @GHC.Types.LiftedRep -> N2 @GHC.Types.LiftedRep
    • In the definition of data constructor ‘MkN2’
      In the newtype declaration for ‘N2’