[GHC] #11172: Turning on optimisations produces SEGFAULT or Impossible case alternative

[GHC]

#11172: Turning on optimisations produces SEGFAULT or Impossible case alternative
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        Reporter:  nh2               |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.10.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Runtime crash     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by nh2):

 Replying to [comment:12 bgamari]:
 > Hmm, I'm afraid I'm having some trouble reproducing this on 7.10.2,
 > {{{
 > Module.hs:34:1: Warning:
 >     The import of ‘Control.Applicative’ is redundant
 > }}}

 @bgamari: I think you are on the `master` branch - for reproducing the
 segfault you need to go on the `segfault` branch of my repo, and on that
 one the `Control.Applicative` import is on a different line than in your
 warning: https://github.com/fpco/impossible-case-alternative-
 repro/blob/segfault/Module.hs#L44

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11172#comment:14>
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