[GHC] #14346: 8.2.1 regression: heap corruption after safe foreign calls

[GHC]

#14346: 8.2.1 regression: heap corruption after safe foreign calls
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        Reporter:  andrewchen        |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.5
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Runtime crash     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #15260            |  Differential Rev(s):  Phab:D5020
       Wiki Page:                    |
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Comment (by bgamari):

 Very sorry about that hsyl20. This was a case where we had temporary fix
 which we desperately wanted to improve upon and therefore only merged it
 to `ghc-8.2`. However, we then weren't able to finish the real fix
 (`with#`, #14375) before 8.4 and the hack was never ported to `master`.
 I've cherry-picked the fix onto `ghc-8.4`, `ghc-8.6`, and `master`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14346#comment:35>
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