[GHC] #12809: TYPE 'UnboxedTupleRep is still a lie

[GHC]

#12809: TYPE 'UnboxedTupleRep is still a lie
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        Reporter:  goldfire          |                Owner:  goldfire
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:  fixed             |             Keywords:
                                     |  LevityPolymorphism
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
                                     |  typecheck/should_run/T12809
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by RyanGlScott):

 Thanks, goldfire!

 I'll try to revisit the fixes for #11723, #11724, and #11509 at some
 point. I believe they all put in checks that forbade the use of
 `UnboxedTupleRep` and `UnboxedSumRep` in deriving because it was assuming
 the inadequacies of the old system for levity polymorphism, but now that's
 it's overhauls, I don't believe those checks are required anymore.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12809#comment:8>
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