[GHC] #10191: Interactive linker crash when partially applying seq#

[GHC]

#10191: Interactive linker crash when partially applying seq#
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              Reporter:  mniip           |             Owner:
                  Type:  bug             |            Status:  new
              Priority:  low             |         Milestone:
             Component:  GHCi            |           Version:  7.8.4-rc1
              Keywords:                  |  Operating System:  Linux
          Architecture:  x86_64 (amd64)  |   Type of failure:  GHCi crash
             Test Case:                  |        Blocked By:
              Blocking:                  |   Related Tickets:
Differential Revisions:                  |
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 Consider the following commands:
 {{{#!hs
 :set -XMagicHash
 import GHC.IO
 import GHC.Prim
 IO (seq# ())
 }}}
 When the last statement is run in GHCi, the following error message is
 displayed:
 {{{
 ByteCodeLink.lookupCE(primop)
 During interactive linking, GHCi couldn't find the following symbol:
   ghczmprim_GHCziPrimopWrappers_seqzh_closure
 This may be due to you not asking GHCi to load extra object files,
 archives or DLLs needed by your current session.  Restart GHCi, specifying
 the missing library using the -L/path/to/object/dir and -lmissinglibname
 flags, or simply by naming the relevant files on the GHCi command line.
 Alternatively, this link failure might indicate a bug in GHCi.
 If you suspect the latter, please send a bug report to:
   glasgow-haskell-bugs at haskell.org
 }}}
 The expression works if I eta-unreduce the `seq#` call: `IO (\x -> seq# ()
 x)`.
 The problem seems to be exclusive to GHCi: if you put that expression in a
 file, it works fine when compiled by GHC, and even GHCi works fine when
 using the resulting `.o` file.
 When there's no `.o` GHCi still crashes, and eta-unreduction doesn't help
 anymore (something to with optimizations I guess).

 I can also reproduce this on the Linux-x86 architecture.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10191>
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