[GHC] #9069: -XDeriveTraversable should imply -XDeriveFunctor and -XDeriveFoldable

[GHC]

#9069: -XDeriveTraversable should imply -XDeriveFunctor and -XDeriveFoldable
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        Reporter:  sjoerd_visscher   |            Owner:
            Type:  feature request   |           Status:  patch
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.8.2
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by simonpj):

 Ah -- but you forgot to update the user manual!

 Also can you just articulate the reasoning behind having
 `-XDeriveTraversable` imply the other two, and perhaps summarise that
 reasoning in the user-manual entry?

 Thanks

 Simon

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9069#comment:4>
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