[GHC] #5960: Show instance for Digraph.Forest overlaps with Show [a]

[GHC]

#5960: Show instance for Digraph.Forest overlaps with Show [a]
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 Reporter:  SimonHengel       |          Owner:                  
     Type:  bug               |         Status:  new             
 Priority:  normal            |      Component:  GHC API         
  Version:  7.4.1             |       Keywords:                  
       Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
  Failure:  None/Unknown      |       Testcase:                  
Blockedby:                    |       Blocking:                  
  Related:                    |  
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Comment(by SimonHengel):

 I think the solution is to use a newtype for Forest.  I'm happy to provide
 a patch.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5960#comment:1>
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