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

[GHC]

#9111: base should export Typeable instances of its promoted data constructors
-------------------------------------+------------------------------------
        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:
-------------------------------------+------------------------------------

Comment (by hvr):

 Replying to [comment:14 simonpj]:
 > > {{{
 > > Failed to load interface for ‘Data.Typeable.Internal’
 > > }}}

 btw, that message is just asking to add an `import Data.Typeable.Internal`
 in the module triggering that error (which often isn't possible due to
 import-cycles)

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

 Adding `default-extension: AutoDeriveTypeable` to `base.cabal` is one way.
 But a more interesting case to try out is to enable `AutoDeriveTypeable`
 just inside a single module such as `GHC/Flaot.lhs` which doesn't `import
 Data.Typeable`

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9111#comment:15>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler