[GHC] #15586: Compilation panic! (the 'impossible' happened)

[GHC]

#15586: Compilation panic! (the 'impossible' happened)
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        Reporter:  subaruru          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.4.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #15499            |  Differential Rev(s):  Phab:D5118
       Wiki Page:                    |
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Changes (by RyanGlScott):

 * os:  Linux => Unknown/Multiple
 * architecture:  x86_64 (amd64) => Unknown/Multiple
 * related:   => #15499


Comment:

 For the sake of historical curiosity: this was caused by the same bug that
 triggered #15499, as it requires a record update on a data constructor
 where an existential type variable comes before a universal one.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15586#comment:4>
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