Levity polymorphism panic in GHCi

With current master,

$ ghci
GHCi, version 8.1.20170126: http://www.haskell.org/ghc/  :? for help
Loaded GHCi configuration from /home/ben/.ghci
λ> import GHC.Exts
λ> :set -XTypeApplications -XMagicHash -XTypeInType
λ> data TypeRep (a :: k) = TypeRep
λ> let typeRepKind = undefined :: TypeRep (a :: k) -> TypeRep k
λ> let typeRep = undefined :: TypeRep (a :: k)
λ> let x = typeRepKind (typeRep @(Maybe Int#))
ghc: panic! (the 'impossible' happened)
  (GHC version 8.1.20170126 for x86_64-unknown-linux):
	isUnliftedType
  forall (a :: TYPE q). a :: TYPE q
  Call stack:
      CallStack (from HasCallStack):
        prettyCurrentCallStack, called at compiler/utils/Outputable.hs:1166:58 in ghc:Outputable
        callStackDoc, called at compiler/utils/Outputable.hs:1170:37 in ghc:Outputable
        pprPanic, called at compiler/types/Type.hs:1869:10 in ghc:Type

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

Trac metadata

Trac field	Value
Version	8.0.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	high
Resolution	Unresolved
Component	Compiler
Test case
Differential revisions
BlockedBy
Related
Blocking
CC	goldfire
Operating system
Architecture