[GHC] #8132: Warning for Typeable instances misplaced

[GHC]

#8132: Warning for Typeable instances misplaced
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        Reporter:  scottgw                       |            Owner:
            Type:  bug                           |  dreixel
        Priority:  normal                        |           Status:  new
       Component:  Compiler                      |        Milestone:
      Resolution:                                |          Version:  7.7
Operating System:  Unknown/Multiple              |         Keywords:
 Type of failure:  Incorrect warning at          |     Architecture:
  compile-time                                   |  Unknown/Multiple
       Test Case:                                |       Difficulty:
        Blocking:                                |  Unknown
                                                 |       Blocked By:
                                                 |  Related Tickets:
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Comment (by dreixel):

 Replying to [comment:7 simonpj]:
 > I'm open to advice.  Two alternatives make sense to me:

 Well, I still think keeping the current behaviour in HEAD (perhaps with an
 improved warning in this case) is an option. Handwritten `Typeable`
 instances will indeed break, but most handwritten instances I've seen are
 for `Typeable1` etc. We could also forego the `typeOf -> typeRep` name
 change; I don't think that it's really necessary, and it might reduce the
 amount of code that breaks. Or we can let `Typeable` have both (the new)
 `typeRep` and (the old) `typeOf`, with the latter having a default
 definition in terms of the former.

 This being said, if I would have to choose between Simon's two options,
 I'd also prefer making the breaking change right now.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8132#comment:9>
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