T17423.hs:19:13: error:
    • Proc patterns cannot use existential or GADT data constructors
    • In the pattern: DecoBool i c
      In the expression:
        proc (DecoBool i c) -> do i1 <- id -< i
                                  c1 <- id -< c
                                  returnA -< DecoBool i1 c1
      In an equation for ‘decoBoolDialog’:
          decoBoolDialog
            = proc (DecoBool i c) -> do i1 <- id -< i
                                        c1 <- id -< c
                                        ....