[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
-------------------------------------+-------------------------------------
        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:
-------------------------------------+-------------------------------------
Changes (by thomie):

 * status:  new => closed
 * resolution:   => duplicate
 * related:   => #9086


Comment:

 I found the commit that fixed this:
 55e7ab1210975e6276f3cab3ac0e1f35bcd772f0
 {{{
 Author: Gintautas Miliauskas <>
 Date:   Sun Jun 8 11:49:29 2014 +0000

     Do not print the result of 'main' after invoking ':main' (fixes
 #9086).
 }}}

 Since it has a test already, we don't have to do anything here.

 Berdes: please have a look at that commit and [wiki:Building/RunningTests]
 to see how the testsuite works.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9991#comment:2>
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