[GHC] #15163: non coercion variable in coVarKindsTypesRole

[GHC]

#15163: non coercion variable in coVarKindsTypesRole
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        Reporter:  alpmestan         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.5
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:  T14732
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"86bba7d519fb6050f78b7e3bac2b3f54273fd70e/ghc" 86bba7d/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="86bba7d519fb6050f78b7e3bac2b3f54273fd70e"
 Add missing check to isReflCoVar_maybe

 isReflCoVar_maybe is called, by CoreLint, on all sorts of
 Vars (tyvars, term vars, coercion vars).  But it was silently
 assuming that it was always called on a CoVar, and as a result
 could crash fatally.  This is the immediate cause of the panic
 in Trac #15163.

 It's easy to fix.

 NB: this does not completely fix Trac #15163; more to come
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15163#comment:1>
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