[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            |   Component:  Compiler                         
     Version:  6.12.3            |    Keywords:                                   
    Testcase:                    |   Blockedby:                                   
          Os:  Unknown/Multiple  |    Blocking:                                   
Architecture:  Unknown/Multiple  |     Failure:  Incorrect warning at compile-time
---------------------------------+------------------------------------------
 Here is a minimal sample module:

 {{{
 module Warning (module Prelude, module Data.List) where

 import Prelude
 import Data.List
 }}}

 This module results in a lot of warnings like this one:
 {{{
 Warning.hs:1:33:
     Warning: `foldl1' is exported by `module Data.List' and `module
 Prelude'
 }}}

 However, in this case, both occurrences of the identifier
 refer to the same entity `foldl1` that is defined in module
 `Data.List`. In such a case, I do not think that a warning
 should be reported.

 Occurs with both 6.12.3 and 7.0.1. Haven't tested other versions.

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