[GHC] #13750: GHC produces incorrect coercions in hairy code

[GHC]

#13750: GHC produces incorrect coercions in hairy code
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        Reporter:  dfeuer            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.2.2
       Component:  Compiler          |              Version:  8.2.1-rc2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Runtime crash     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #13429            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 You may not be surprised, but I am.  But I'm also delighted -- I was not
 looking forward to discovering what was happening.

 I hope that it's actually fixed, not just masked.  But let's see if
 Andres's original problem is fixed.  If it is, let's declare victory and
 close.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13750#comment:13>
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