T21605b.hs:6:13: error: [GHC-76037]
    Not in scope: ‘Prelude.true’
    NB: the module ‘Prelude’ does not export ‘true’.
    Suggested fix:
      Perhaps use one of these:
        data constructor ‘Prelude.True’ (imported from Prelude),
        type constructor or class ‘Prelude.Num’ (imported from Prelude),
        type constructor or class ‘Prelude.Ord’ (imported from Prelude)