[GHC] #15748: panic

[GHC]

#15748: panic
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           Reporter:  awf            |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.6.1
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 {{{
 GHCi, version 8.4.3: http://www.haskell.org/ghc/  :? for help
 Prelude> :print getChar >>= return
 ghc.exe: panic! (the 'impossible' happened)
   (GHC version 8.4.3 for x86_64-unknown-mingw32):
         isUnliftedType
   t1_a1tM[rt] :: TYPE t_a1tL[rt]
   Call stack:
       CallStack (from HasCallStack):
         callStackDoc, called at compiler\utils\Outputable.hs:1150:37 in
 ghc:Outputable
         pprPanic, called at compiler\\types\\Type.hs:1939:10 in ghc:Type

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

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15748>
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