[GHC] #10367: "ghc: panic! (the 'impossible' happened)"

[GHC]

#10367: "ghc: panic! (the 'impossible' happened)"
-------------------------------------+-------------------------------------
              Reporter:  bgwines     |             Owner:
                  Type:  bug         |            Status:  new
              Priority:  normal      |         Milestone:
             Component:  Compiler    |           Version:  7.10.1
              Keywords:  panic       |  Operating System:  MacOS X
          Architecture:              |   Type of failure:  Runtime crash
  Unknown/Multiple                   |        Blocked By:
             Test Case:              |   Related Tickets:
              Blocking:              |
Differential Revisions:              |
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 When running tasty-hunit tests through `cabal repl`, I get the following
 error:


 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.8.3 for x86_64-apple-darwin):
         Loading temp shared object failed:
 dlopen(/var/folders/l6/v2vhn_3j6bb1yvp6k5sh2hv80000gp/T/ghc80357_0/ghc80357_61.dylib,
 9): Symbol not found:
 __hpc_tickboxes_horsezmcontrolzm0zi1zi0zi0_HorseziCommands_hpc
   Referenced from:
 /var/folders/l6/v2vhn_3j6bb1yvp6k5sh2hv80000gp/T/ghc80357_0/ghc80357_61.dylib
   Expected in: flat namespace
  in
 /var/folders/l6/v2vhn_3j6bb1yvp6k5sh2hv80000gp/T/ghc80357_0/ghc80357_61.dylib

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 }}}

 I have a hunch that it's because I enabled the following flags in my
 .cabal file, since I didn't get the exception before adding them:

 {{{
 Test-Suite test-horse
     ...
     GHC-Options:      -fhpc -hpcdir dist/hpc/horse-control-1.0
 }}}

 When I run the tests via `cabal test`, I don't get the exception.

 I've created a branch that showcases the crash: https://github.com/bgwines
 /horse-control/tree/ghc-panic

 Repro steps:
 * clone repo
 * cd to repo
 * run `cabal repl`
 * run `:l Tests/test-horse.hs`
 * run `main`

 Reproducability: 100%

 Please feel free to contact me if there's information lacking, here! :)

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10367>
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