[GHC] #10549: floatExpr tick break<2>

[GHC]

#10549: floatExpr tick break<2>
-------------------------------------+-------------------------------------
              Reporter:              |             Owner:
  NeilMitchell                       |            Status:  new
                  Type:  bug         |         Milestone:
              Priority:  normal      |           Version:  7.11
             Component:  Compiler    |  Operating System:  Unknown/Multiple
              Keywords:              |   Type of failure:  None/Unknown
          Architecture:              |        Blocked By:
  Unknown/Multiple                   |   Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------
 When running the Shake test suite against GHC HEAD I get:

 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.11.20150615 for x86_64-unknown-linux):
         floatExpr tick break<2>()
 }}}

 Full log at https://travis-ci.org/ndmitchell/shake/jobs/67636563. The
 command line that produced it is:

 {{{
 runhaskell -ignore-package=hashmap -ioutput/docs/ -isrc
 output/docs/Main.hs
 }}}

 If this seems like a legitimate bug that you don't already know about and
 are interested in tracking down, I'll try and grab the output/docs
 directory (it's on a remote machine I don't have access to on a different
 OS with a compiler I don't have installed, so it's not trivial to find it,
 but should be possible).

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10549>
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