[GHC] #15609: No skolem info panic: Static pointers and holes

[GHC]

#15609: No skolem info panic: Static pointers and holes
-------------------------------------+-------------------------------------
           Reporter:  mpickering     |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:  8.6.1
          Component:  Compiler       |           Version:  8.4.3
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 The following program panics:

 {{{
 {-# LANGUAGE StaticPointers #-}
 {-# LANGUAGE GADTs #-}
 module Panic where

 data Closure a where

 foo :: (Closure a -> Closure b) -> Closure (a -> b)
 foo f = static _
 }}}

 {{{
 src/Panic.hs:8:16: error:ghc: panic! (the 'impossible' happened)
   (GHC version 8.6.0.20180810 for x86_64-unknown-linux):
         No skolem info:
   [a_a5rt[sk:1], b_a5ru[sk:1]]
   Call stack:
       CallStack (from HasCallStack):
         callStackDoc, called at compiler/utils/Outputable.hs:1164:37 in
 ghc:Outputable
         pprPanic, called at compiler/typecheck/TcErrors.hs:2851:5 in
 ghc:TcErrors

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

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15609>
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