[GHC] #15804: GHC panic (Visible kind application diff): data T :: (a :: k) -> *

[GHC]

#15804: GHC panic (Visible kind application diff): data T :: (a :: k) -> *
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.6.1
      Resolution:                    |             Keywords:
                                     |  TypeApplications
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Iceland_jack):

 Just built head and it panics the same

 {{{
 $ ./ghc-stage2 -ignore-dot-ghci --interactive ~/hs/583.hs
 GHCi, version 8.7.20181025: http://www.haskell.org/ghc/  :? for help
 [1 of 1] Compiling Main             ( /home/baldur/hs/583.hs, interpreted
 )
 ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 8.7.20181025 for x86_64-unknown-linux):
         ASSERT failed!
   Type-correct unfilled coercion hole {co_a1xI}
   Call stack:
       CallStack (from HasCallStack):
         callStackDoc, called at compiler/utils/Outputable.hs:1160:37 in
 ghc:Outputable
         pprPanic, called at compiler/utils/Outputable.hs:1219:5 in
 ghc:Outputable
         assertPprPanic, called at compiler/typecheck/TcHsSyn.hs:1805:99 in
 ghc:TcHsSyn

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug

 >
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15804#comment:3>
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