Panic when using StaticPointers with typed holes

Adding a type hole when there is a type variable in StaticPtr throws a GHC panic:

{-# LANGUAGE StaticPointers #-}

module Foo where

import Data.Typeable
import GHC.StaticPtr

foo :: Typeable a => StaticPtr a
foo = static _ 

[1 of 1] Compiling Foo              ( test.hs, test.o )

test.hs:9:14: error:ghc: panic! (the 'impossible' happened)
  (GHC version 8.4.1 for x86_64-unknown-linux):
	No skolem info:
  [a_aD2[sk:2]]
  Call stack:
      CallStack (from HasCallStack):
        callStackDoc, called at compiler/utils/Outputable.hs:1150:37 in ghc:Outputable
        pprPanic, called at compiler/typecheck/TcErrors.hs:2945:5 in ghc:TcErrors

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

This panics on both GHC 8.2.2 and 8.4.1.

Trac metadata

Trac field	Value
Version	8.4.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC
Operating system
Architecture