[GHC] #11251: isInstance does not work on Typeable with base-4.8 anymore

[GHC]

#11251: isInstance does not work on Typeable with base-4.8 anymore
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        Reporter:  songzh            |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Template Haskell  |              Version:  7.10.1
      Resolution:                    |             Keywords:  Typeable,
                                     |  isInstance
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 simonpj):

 Re comment:3, we automatically derive a `Typeable` instance for every
 type, so it should probably be an error to derive it explicitly.  Does
 everyone agree?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11251#comment:5>
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