[GHC] #13255: aws package fails to build with master

[GHC]

#13255: aws package fails to build with master
-------------------------------------+-------------------------------------
        Reporter:  bgamari           |                Owner:  bgamari
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by RyanGlScott):

 Yep, a profiled GHC HEAD is crucial here. I couldn't reproduce this with a
 profiled 8.0.2, but with a profiled GHC HEAD, I get:

 {{{
 $ cabal build
 Building aws-0.16...
 Preprocessing library aws-0.16...
 [69 of 78] Compiling Aws.DynamoDb.Core ( Aws/DynamoDb/Core.hs,
 dist/build/Aws/DynamoDb/Core.p_o )

 <no location info>: error:
     ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 8.1.20170213 for x86_64-unknown-linux):
         completeCall
   $wloop_length_s1bOu
   Stop[BoringCtxt] Int# -> Int# -> Int
   Call stack:
       CallStack (from HasCallStack):
         prettyCurrentCallStack, called at
 compiler/utils/Outputable.hs:1197:58 in ghc:Outputable
         callStackDoc, called at compiler/utils/Outputable.hs:1201:37 in
 ghc:Outputable
         pprPanic, called at compiler/simplCore/Simplify.hs:1598:9 in
 ghc:Simplify
 CallStack (from -prof):
   SimplCore.SimplTopBinds (compiler/simplCore/SimplCore.hs:729:29-64)
   SimplCore.Simplify (compiler/simplCore/SimplCore.hs:426:40-55)
   HscMain.Core2Core (compiler/main/HscMain.hs:1170:7-42)
   HscMain.hscSimplify' (compiler/main/HscMain.hs:(1167,1)-(1170,42))
   HscMain.finish (compiler/main/HscMain.hs:(728,1)-(740,20))
   HscMain.hscIncrementalCompile
 (compiler/main/HscMain.hs:(639,1)-(694,32))
   GhcMake.upsweep_mod.compile_it
 (compiler/main/GhcMake.hs:(1380,13)-(1382,66))
   GhcMake.upsweep_mod (compiler/main/GhcMake.hs:(1328,1)-(1482,49))
   GhcMake.parUpsweep_one.withSem (compiler/main/GhcMake.hs:1104:13-66)
   GhcMake.parUpsweep_one (compiler/main/GhcMake.hs:(1009,1)-(1164,65))
   GhcMake.parUpsweep.\.spawnWorkers.\.\
 (compiler/main/GhcMake.hs:(867,43)-(918,49))
   GhcMake.parUpsweep.\.spawnWorkers.\
 (compiler/main/GhcMake.hs:(867,13)-(918,49))
   GhcMake.parUpsweep.\.spawnWorkers
 (compiler/main/GhcMake.hs:(866,11)-(918,49))
   GhcMake.parUpsweep.\.finallySyncSession
 (compiler/main/GhcMake.hs:(832,9)-(834,30))
   GhcMake.parUpsweep.\ (compiler/main/GhcMake.hs:(829,62)-(949,44))
   GhcMake.parUpsweep (compiler/main/GhcMake.hs:(796,1)-(979,36))
   GhcMake.load'.upsweep_fn (compiler/main/GhcMake.hs:(351,9)-(352,41))
   GhcMake.load'.checkHowMuch (compiler/main/GhcMake.hs:(233,9)-(235,27))
   GhcMake.load' (compiler/main/GhcMake.hs:(210,1)-(439,38))
   GhcMake.load (compiler/main/GhcMake.hs:(202,1)-(204,44))
   GHC.withCleanupSession (compiler/main/GHC.hs:(450,1)-(459,37))
   GHC.runGhc (compiler/main/GHC.hs:(425,1)-(430,26))
   GHC.defaultErrorHandler (compiler/main/GHC.hs:(365,1)-(397,7))

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

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13255#comment:7>
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