[GHC] #14880: GHC panic: updateRole

[GHC]

#14880: GHC panic: updateRole
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        Reporter:  RyanGlScott       |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       Component:  Compiler (Type    |              Version:  8.2.2
  checker)                           |
      Resolution:                    |             Keywords:  TypeInType
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #15076            |  Differential Rev(s):  Phab:D4769
       Wiki Page:                    |
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Comment (by tdammers):

 Oh no. What I was trying to say is that (3) seems to be responsible; I
 could write an `FV` flavor to verify it, but it would amount to pretty
 much just `VarSet`, just wrapped in a record together with two other
 fields that we won't use.

 In theory it should be interesting to take our FV and *only* change (3),
 but keep (1) and (2), except that we already suspected that neither of
 them does anything significant here, and we have already ruled them out as
 culprits individually.

 But I'll do it anyway, even if it's just to make sure I didn't miss
 anything in embarrassing ways.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14880#comment:90>
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