[GHC] #11239: GHC HEAD: cannot bootstrap HEAD with HEAD

[GHC]

#11239: GHC HEAD: cannot bootstrap HEAD with HEAD
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        Reporter:  heisenbug         |                Owner:
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Building GHC      |  Unknown/Multiple
  failed                             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by gkaracha):

 If it is related to #11195, I may have the solution real soon. Since the
 additional expressivity
 about guards came with a big price, we will have a flag (or more) for more
 precise control over
 how hard the checker tries to reason about pattern matching. At the
 moment, with `-Wall` we enable
 the whole check, no matter what the cost is. I expect to have the patch
 before the end of the week,
 and I hope it fixes this along with #11195. If you have any more
 information about the file that
 causes the problem please let me know!

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11239#comment:3>
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