[GHC] #13695: Highly nested UNPACKed data causes panic

[GHC]

#13695: Highly nested UNPACKed data causes panic
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        Reporter:  ryanreich     |                Owner:  (none)
            Type:  bug           |               Status:  new
        Priority:  high          |            Milestone:  8.2.1
       Component:  Compiler      |              Version:  8.2.1-rc2
      Resolution:                |             Keywords:
Operating System:  Linux         |         Architecture:  Unknown/Multiple
 Type of failure:  None/Unknown  |            Test Case:
      Blocked By:                |             Blocking:
 Related Tickets:  #3990         |  Differential Rev(s):
       Wiki Page:                |
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Comment (by RyanGlScott):

 I can't reproduce this error with GHC 8.2.1 or HEAD:

 {{{
 $ /opt/ghc/8.2.1/bin/ghc -fforce-recomp -O2 BigWord.hs
 [1 of 3] Compiling BigWordClass     ( BigWordClass.hs, BigWordClass.o )
 [2 of 3] Compiling BigWordUnpack    ( BigWordUnpack.hs, BigWordUnpack.o )
 [3 of 3] Compiling BigWord          ( BigWord.hs, BigWord.o )
 }}}

 Is there something in particular I need to do to trigger this panic?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13695#comment:2>
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