No skolem info panic: Static pointers and holes

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

Trac metadata

Trac field	Value
Version	8.4.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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