GHC Panic with TypeInType / levity polymorphism

{-# Language TypeInType #-}
{-# Language TypeOperators, DataKinds, PolyKinds #-}

import Data.Kind
import GHC.Types (TYPE)

data Exp :: [TYPE rep] -> TYPE rep -> Type where
  Lam :: Exp (a:xs) b -> Exp xs (a -> b)

gives

$ ghci -ignore-dot-ghci hs/126-bug.hs
GHCi, version 8.3.20171122: http://www.haskell.org/ghc/  :? for help
[1 of 1] Compiling Main             ( hs/126-bug.hs, interpreted )
ghc-stage2: panic! (the 'impossible' happened)
  (GHC version 8.3.20171122 for x86_64-unknown-linux):
	zonkTcTyVarToVar
  'LiftedRep
  Call stack:
      CallStack (from HasCallStack):
        callStackDoc, called at compiler/utils/Outputable.hs:1147:37 in ghc:Outputable
        pprPanic, called at compiler/typecheck/TcType.hs:1640:17 in ghc:TcType

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

caused by TypeInType. Removing the first line, we get an error

GHCi, version 8.3.20171122: http://www.haskell.org/ghc/  :? for help
[1 of 1] Compiling Main             ( hs/126-bug.hs, interpreted )

hs/126-bug.hs:7:19: error:
    • Expected kind ‘GHC.Types.RuntimeRep’, but ‘rep’ has kind ‘*’
    • In the first argument of ‘TYPE’, namely ‘rep’
      In the kind ‘[TYPE rep] -> TYPE rep -> Type’
  |
7 | data Exp :: [TYPE rep] -> TYPE rep -> Type where
  |                   ^^^

hs/126-bug.hs:7:32: error:
    • Expected kind ‘GHC.Types.RuntimeRep’, but ‘rep’ has kind ‘*’
    • In the first argument of ‘TYPE’, namely ‘rep’
      In the kind ‘[TYPE rep] -> TYPE rep -> Type’
  |
7 | data Exp :: [TYPE rep] -> TYPE rep -> Type where
  |                                ^^^
Failed, no modules loaded.
Prelude> 

Trac metadata

Trac field	Value
Version	8.3
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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