testsuite/tests/deriving/should_fail/T3833.stderr


1
2
3
4
5
6


T3833.hs:9:1:
    Can't make a derived instance of ‛Monoid (DecodeMap e)’:
      ‛Monoid’ is not a derivable class
      Try GeneralizedNewtypeDeriving for GHC's newtype-deriving extension
    In the stand-alone deriving instance for ‛Monoid (DecodeMap e)’