[GHC] #9111: base should export Typeable instances of its promoted data constructors

[GHC]

#9111: base should export Typeable instances of its promoted data constructors
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        Reporter:  goldfire          |            Owner:
            Type:  feature request   |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.8.2
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by simonpj):

 Replying to [comment:9 hvr]:
 > Replying to [comment:8 simonpj]:
 > > I think we should probably switch it on for the entire `base` package,
 and the chair of the core libraries committee seems to agree.  That would
 be simpler than a lot of ad-hoc instances.
 >
 > Btw, I just tried to enable it globally in order to get a list of
 additional `Typeable` instances becoming available by that, but you have
 to avoid using `AutoDeriveTypeable` at the same time with
 `NoImplicitPrelude`, as otherwise you get the error
 >
 > {{{
 > Failed to load interface for ‘Data.Typeable.Internal’
 > }}}

 Can you explain how to reproduce this error.  Just add
 `AutoDeriveTypeable` to `base.cabal`?  Or what?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9111#comment:14>
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