[GHC] #3743: type checker fails to infer an implicit parameter constraint in the presence of existential types.

[GHC]

#3743: type checker fails to infer an implicit parameter constraint in the
presence of existential types.
---------------------------+------------------------------------------------
  Reporter:  int-e         |          Owner:                  
      Type:  bug           |         Status:  closed          
  Priority:  normal        |      Milestone:  7.2.1           
 Component:  Compiler      |        Version:  6.13            
Resolution:  fixed         |       Keywords:                  
  Testcase:  T3743         |      Blockedby:                  
Difficulty:                |             Os:  Unknown/Multiple
  Blocking:                |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown  |  
---------------------------+------------------------------------------------
Changes (by igloo):

  * status:  new => closed
  * testcase:  => T3743
  * resolution:  => fixed


Comment:

 This now works. I've added a test.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3743#comment:5>
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