[GHC] #13171: panic on negative literal in case on Word

[GHC]

#13171: panic on negative literal in case on Word
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        Reporter:  rwbarton          |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * version:  8.1 => 8.0.1


Comment:

 I compiled GHC 8.0.1 with the `devel2` flavor and it still gave the same
 panic:

 {{{
 $ ghc4/inplace/bin/ghc-stage2 --interactive Bug.hs
 GHCi, version 8.0.1: http://www.haskell.org/ghc/  :? for help
 Loaded GHCi configuration from /home/rgscott/.ghci
 [1 of 1] Compiling Case             ( Bug.hs, interpreted )
 ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 8.0.1 for x86_64-unknown-linux):
         ASSERT failed!
   CallStack (from HasCallStack):
   assertPprPanic, called at compiler/basicTypes/Literal.hs:224:75 in
 ghc:Literal
   -1
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13171#comment:1>
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