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

[GHC]

#11172: Turning on optimisations produces 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):

 (Small digression:)

 Replying to [comment:1 rwbarton]:
 > Are you sure you have seen GHC ask you to report a bug when running a
 program compiled by GHC (other than GHC itself)? I don't think that ever
 happens.

 @rwbarton: Actually, I did find such a case, I have one right here: A
 yesod webserver that when compiled without `-threaded`, and Ctrl-C'd,
 throws the following error:


 {{{
 src/main/Main Development
 ^CMain: internal error: removeFromQueues: 22294
     (GHC version 7.10.2 for x86_64_unknown_linux)
     Please report this as a GHC bug:
 http://www.haskell.org/ghc/reportabug
 Aborted (core dumped)
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11172#comment:10>
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