[GHC] #9480: Segfault in GHC API code using Shelly

[GHC]

#9480: Segfault in GHC API code using Shelly
-------------------------------------+-------------------------------------
       Reporter:  agibiansky         |                   Owner:
           Type:  bug                |                  Status:  new
       Priority:  normal             |               Milestone:
      Component:  GHC API            |                 Version:  7.8.3
       Keywords:                     |        Operating System:  Linux
   Architecture:  Unknown/Multiple   |         Type of failure:  Runtime
     Difficulty:  Unknown            |  crash
     Blocked By:                     |               Test Case:
Related Tickets:                     |                Blocking:
                                     |  Differential Revisions:
-------------------------------------+-------------------------------------
 A segfault occurs when using the GHC API with Shelly. I do not know why.

 Here is a code snippet that triggers it:

 {{{#!hs
 import GHC
 import GHC.Paths ( libdir )
 import DynFlags

 main = runGhc (Just libdir) $ do
   dflags <- getSessionDynFlags
   setSessionDynFlags $ dflags { hscTarget = HscInterpreted,
           ghcLink = LinkInMemory }
   imports <- mapM parseImportDecl ["import Shelly", "import Prelude"]
   setContext $ map IIDecl imports
   runStmt "shelly undefined" RunToCompletion
 }}}

 Note that on Mac OS X, this has no output whatsoever. The segfault occurs
 on Ubuntu 14.04, with `uname -a` outputting the following:

 {{{
 Linux yed 3.13.0-34-generic #60-Ubuntu SMP Wed Aug 13 15:45:27 UTC 2014
 x86_64 x86_64 x86_64 GNU/Linux
 }}}

 I cannot find any way to get this to work and have no idea what's up with
 this or why shelly triggers it.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9480>
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