[GHC] #9858: Typeable instances should be kind-aware

[GHC]

#9858: Typeable instances should be kind-aware
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        Reporter:  dreixel           |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  highest           |               Milestone:  7.10.1
       Component:  Compiler          |                 Version:  7.9
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
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Comment (by rwbarton):

 In that case perhaps we should advertise the new automatic Typeable
 deriving behavior as experimental  in 7.10, so that users can decide
 whether they want to rely on it or not.

 Also, I think it's definitely correct that (as it is currently) warn-
 deriving-typeable ''not'' be enabled by `-Wall`. We can turn on the
 warning in 7.12.

 By the way, we may want to use a similar mechanism of generating evidence
 at the call site to handle #9557. For that problem, we would certainly
 need to track whether or not the class was derived at the definition site.
 So, I don't actually expect the effort to be useless. But the timing may
 be wrong here, unfortunately.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9858#comment:70>
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