[GHC] #10089: feature: warn about unused data definitions (with typeclass instances)

[GHC]

#10089: feature: warn about unused data definitions (with typeclass instances)
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        Reporter:  slyfox            |                Owner:  dfordivam
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.8.4
      Resolution:                    |             Keywords:  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #3221             |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by dfordivam):

 * related:  3221 => #3221


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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10089#comment:5>
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