[GHC] #9991: runghc shows the value produced by main when its type is a non-() Show instance

[GHC]

#9991: runghc shows the value produced by main when its type is a non-() Show
instance
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        Reporter:  shachaf           |                   Owner:
            Type:  task              |                  Status:  closed
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.8.4
      Resolution:  duplicate         |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:  #9086             |  Differential Revisions:
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Comment (by ezyang):

 Aha, I missed that test because I grepped for runghc and this test is
 using GHCi interactive to run main.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9991#comment:3>
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