[GHC] #10533: Typechecker behaves differently on Phab and on Mac

[GHC]

#10533: Typechecker behaves differently on Phab and on Mac
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        Reporter:  goldfire          |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.11
      Resolution:                    |                Keywords:
Operating System:  MacOS X           |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
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Comment (by goldfire):

 Replying to [comment:5 rwbarton]:
 > Attached. Your output seems to have additional messages that are enabled
 when `debugIsOn`, so maybe some other debugging output or assertion is
 panicking for you?

 Of course. The panic is an `ASSERT`ion failure. So perhaps the problem is
 happening on all platforms, but only caught in a `DEBUG` build.

 Indeed, your log contains the problematic derived constraint at the end of
 `tryReporters`. It just doesn't bail out.

 So, weirdness resolved, I believe... but now we need to figure out why
 that assertion is failing.

 Modifying ticket accordingly.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10533#comment:6>
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