[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 ryanreich):

 That's odd; it should "work" as-is.  I wonder if I got the ghc version
 wrong?  It's shown in the panic message, though: 8.2.0.20170505.  Just in
 case this is an issue of some more obscure environment, let me post my
 stack.yaml and bigint.cabal as well.  Also, here's my system info:

 {{{
 ryan at thermophile $ uname -a
 Linux thermophile 4.8.0-49-generic #52-Ubuntu SMP Thu Apr 20 09:38:39 UTC
 2017 x86_64 x86_64 x86_64 GNU/Linux

 ryan at thermophile $ free -h
               total        used        free      shared  buff/cache
 available
 Mem:           7.7G        2.3G        1.9G        321M        3.5G
 4.7G
 Swap:          3.7G          0B        3.7G

 ryan at thermophile $ cat /proc/cpuinfo
 processor       : 3 (and 0, 1, 2)
 vendor_id       : GenuineIntel
 cpu family      : 6
 model           : 142
 model name      : Intel(R) Core(TM) i7-7500U CPU @ 2.70GHz
 stepping        : 9
 microcode       : 0x3c
 cpu MHz         : 799.871
 cache size      : 4096 KB
 physical id     : 0
 siblings        : 4
 core id         : 1
 cpu cores       : 2
 apicid          : 3
 initial apicid  : 3
 fpu             : yes
 fpu_exception   : yes
 cpuid level     : 22
 wp              : yes
 flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca
 cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx
 pdpe1gb rdtscp lm constant_tsc art arch_perfmon pebs bts rep_good nopl
 xtopology nonstop_tsc aperfmperf eagerfpu pni pclmulqdq dtes64 monitor
 ds_cpl vmx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid sse4_1 sse4_2 x2apic
 movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm
 3dnowprefetch epb intel_pt tpr_shadow vnmi flexpriority ept vpid fsgsbase
 tsc_adjust bmi1 avx2 smep bmi2 erms invpcid mpx rdseed adx smap clflushopt
 xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify
 hwp_act_window hwp_epp
 bugs            :
 bogomips        : 5800.00
 clflush size    : 64
 cache_alignment : 64
 address sizes   : 39 bits physical, 48 bits virtual
 power management:
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13695#comment:3>
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