[GHC] #14965: GHC 8.4.1 bug: -O + separate compilation + three list fields + concatenation; core-lint fails

[GHC]

#14965: GHC 8.4.1 bug: -O + separate compilation + three list fields +
concatenation; core-lint fails
-------------------------------------+-------------------------------------
        Reporter:  blynn             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.4.1
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by blynn):

 * Attachment "corelint.dump" added.

 dump of -O -dcore-lint

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14965>
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