[GHC] #12212: GHC 8.0.1 crash

[GHC]

#12212: GHC 8.0.1 crash
-------------------------------------+-------------------------------------
           Reporter:  dibblego       |             Owner:
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.1
           Keywords:                 |  Operating System:  Linux
       Architecture:                 |   Type of failure:  Compile-time
  Unknown/Multiple                   |  crash
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:  9160, 10602
Differential Rev(s):                 |         Wiki Page:
-------------------------------------+-------------------------------------
 Attempting to install the geodetics package results in a GHC 8.0.1 crash.

 {{{
 % ghc --version
 The Glorious Glasgow Haskell Compilation System, version 8.0.1
 % uname -a
 Linux moron 4.6.2-1-ARCH #1 SMP PREEMPT Wed Jun 8 08:40:59 CEST 2016
 x86_64 GNU/Linux
 % cabal install geodetics-0.0.4
 ...omitted
 [2 of 9] Compiling Geodetics.Ellipsoids ( src/Geodetics/Ellipsoids.hs,
 dist/dist-sandbox-49e45c7e/build/Geodetics/Ellipsoids.o )
 ghc: panic! (the 'impossible' happened)
   (GHC version 8.0.1 for x86_64-unknown-linux):
         Template variable unbound in rewrite rule
   Variable: cobox_scSX
   Rule "SPEC t @ a @ 'DQuantity @ 'DQuantity @ d @ d' @ 'DQuantity @
 'DQuantity @ d @ d' @ 'DQuantity @ 'DQuantity @ d @ d'"
   Rule bndrs: [cobox_scSX, cobox_scSY, cobox_scSZ, cobox_scT0,
                cobox_scT1, $dKnownVariant_scT2, $dKnownVariant_scT3,
                $dKnownVariant_scT4, $dKnownVariant_scT5,
 $dKnownVariant_scT6,
                $dKnownVariant_scT7, $dNum_scT8]
   LHS args: [TYPE: a_ac0a, TYPE: 'DQuantity, TYPE: 'DQuantity,
              TYPE: d_ac0b, TYPE: d'_ac0c, TYPE: 'DQuantity, TYPE:
 'DQuantity,
              TYPE: d_ac0b, TYPE: d'_ac0c, TYPE: 'DQuantity, TYPE:
 'DQuantity,
              TYPE: d_ac0b, TYPE: d'_ac0c, CO: <d_ac0b * d'_ac0c>_N,
              CO: cobox_scSY, CO: <d_ac0b * d'_ac0c>_N, CO: cobox_scT0,
              CO: cobox_scT1, $dKnownVariant_scT2, $dKnownVariant_scT3,
              $dKnownVariant_scT4, $dKnownVariant_scT5,
 $dKnownVariant_scT6,
              $dKnownVariant_scT7, $dNum_scT8]
   Actual args: [TYPE: a_ac0a, TYPE: 'DQuantity, TYPE: 'DQuantity,
                 TYPE: d_ac0b, TYPE: d'_ac0c, TYPE: 'DQuantity, TYPE:
 'DQuantity,
                 TYPE: d_ac0b, TYPE: d'_ac0c, TYPE: 'DQuantity, TYPE:
 'DQuantity,
                 TYPE: d_ac0b, TYPE: d'_ac0c, CO: <d_ac0b * d'_ac0c>_N,
                 CO: D:R:*[1], CO: <d_ac0b * d'_ac0c>_N, CO: D:R:*[1], CO:
 D:R:*[1],
                 $fKnownVariantDQuantity, $fKnownVariantDQuantity,
                 $fKnownVariantDQuantity, $fKnownVariantDQuantity,
                 $fKnownVariantDQuantity, $fKnownVariantDQuantity,
 $dNum_acqm,
                 tx_aaQW, v_aaQZ]

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

 cabal: Error: some packages failed to install:
 geodetics-0.0.4 failed during the building phase. The exception was:
 ExitFailure 1
 }}}

 Similarity to #10602 and #9160 has been pointed out. I also tried:

 {{{
 % cabal --ghc-options="-O2" install geodetics-0.0.4
 }}}

 with no difference in the crash outcome.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12212>
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