[GHC] #15167: DerivClause list is not populated for (TyConI (DataD ...))

[GHC]

#15167: DerivClause list is not populated for (TyConI (DataD ...))
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        Reporter:  0xd34df00d        |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Template Haskell  |              Version:  8.4.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by 0xd34df00d):

 Thanks for getting to my report!

 Seems like `reifyInstances`'s documentation could also be slightly
 improved: it's not entirely obvious from it right now that it can/should
 be used to get the list of instances for a data type. Indeed, for the
 above example, how does one use it to get something about `Eq, Ord, Show`
 without knowing a priori that those are the classes that `Foo` implements?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15167#comment:2>
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