# Pastebin SL8YmJSc
panic! (the 'impossible' happened)
  (GHC version 8.10.4:
        isUnliftedType

a :: TYPE k0
Call stack:
    CallStack (from HasCallStack):
      callStackDoc, called at compiler\utils\Outputable.hs:1179:37 in ghc:Outputable
      pprPanic, called at compiler\\types\\Type.hs:1973:10 in ghc:Type

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