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This code is rightfully rejected.

-- {-# Language TypeInType #-}
{-# Language RankNTypes, KindSignatures, PolyKinds #-}

import GHC.Types (TYPE)
import Data.Kind

data Lan (g::TYPE rep -> TYPE rep') (h::TYPE rep -> TYPE rep'') a where Lan :: forall xx (g::TYPE rep -> TYPE rep') (h::TYPE rep -> Type) a. (g xx -> a) -> h xx -> Lan g h a

But uncomment first line and it panics

$ ghci2 ~/hs/132-bug.hs
GHCi, version 8.3.20171122: http://www.haskell.org/ghc/  :? for help
[1 of 1] Compiling Main             ( /home/baldur/hs/132-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

> 

Maybe the same as #14555 (closed).

Trac metadata

Trac field	Value
Version	8.2.1
Type	Bug
TypeOfFailure	OtherFailure
Priority	normal
Resolution	Unresolved
Component	Compiler
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