[GHC] #14105: ApplicativeDo causes GHC panic on irrefutable list pattern match

[GHC]

#14105: ApplicativeDo causes GHC panic on irrefutable list pattern match
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        Reporter:  BoteboTsebo       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:  ApplicativeDo
Operating System:  Unknown/Multiple  |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by lippling):

 I think this is not fixed completely. With 8.2.2 I get:


 {{{
 [62 of 63] Compiling Handler.Arena    ( Handler/Arena.hs, .stack-
 work/dist/x86_64-osx/Cabal-2.0.1.0/build/Handler/Arena.o )
     ghc: panic! (the 'impossible' happened)
       (GHC version 8.2.2 for x86_64-apple-darwin):
         isStrictPattern

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

 Disabling ApplicativeDo helps. I don't know what triggers it, yet. If you
 need to know, I'll try to find a minimal example.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14105#comment:5>
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