[GHC] #4478: Exporting the same entity twice should not be a warning

[GHC]

#4478: Exporting the same entity twice should not be a warning
---------------------------------+------------------------------------------
    Reporter:  kosmikus          |        Owner:                                   
        Type:  bug               |       Status:  new                              
    Priority:  normal            |    Milestone:                                   
   Component:  Compiler          |      Version:  6.12.3                           
    Keywords:                    |     Testcase:                                   
   Blockedby:                    |   Difficulty:                                   
          Os:  Unknown/Multiple  |     Blocking:                                   
Architecture:  Unknown/Multiple  |      Failure:  Incorrect warning at compile-time
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Comment(by igloo):

 I think we should warn about these three:
 {{{
 (foldr, foldr)
 (module Data.List, module Data.List)
 (Maybe(..), Just)
 }}}
 but not:
 {{{
 (module Prelude, module Data.List)
 }}}
 and I'm not sure about:
 {{{
 (foldr, module Data.List)
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4478#comment:3>
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