[GHC] #14661: Cannot derive (newtype I a b = I (F a -> F b) deriving newtype Category) for type family F

[GHC]

#14661: Cannot derive (newtype I a b = I (F a -> F b) deriving newtype Category)
for type family F
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  feature request   |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.4.1-alpha1
      Resolution:  wontfix           |             Keywords:
                                     |  DerivingStrategies, deriving,
                                     |  TypeFamilies
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 Iceland_jack):

 Replying to [comment:9 simonpj]:
 > However, the new feature looks tantalisingly close.

 > This won't always work as Ryan points out, but sometimes.
 > And I suppose we could work that out.
 >
 > It seems rather elaborate though!

 I agree that it's tantalising, if you think it's a general enough
 solution, enough “bang for the buck” then re-open. But there is no hurry
 on my end, I'd like more examples that need this.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14661#comment:11>
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