[GHC] #13343: Levity polymorphism-related GHC panic: expectJust zonkTcTyVarToVar

[GHC]

#13343: Levity polymorphism-related GHC panic: expectJust zonkTcTyVarToVar
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.0.1
  checker)                           |             Keywords:
      Resolution:                    |  LevityPolymorphism
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash or panic                     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by goldfire):

 I don't have more time to look into precisely why this is getting through
 the cracks, but that type should be rejected by `TcValidity.check_type`.
 Look for the call to `forAllEscapeErr`.

 In short, that type is malformed because it's kind must mention `v`, which
 is out-of-scope.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13343#comment:1>
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