[GHC] #15629: "No skolem info" panic (GHC 8.6 only)

[GHC]

#15629: "No skolem info" panic (GHC 8.6 only)
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler (Type    |              Version:  8.6.1-beta1
  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:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 Well, I devoted a few mins to trying to see what caused the crash in ghc
 8.6, but it doesn't look related to the patch you identify in comment:3.
 Still, since it is working, I'm disinclined to invest more effort in
 debugging 8.6!

 I'll add a regression test and close this.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15629#comment:8>
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