[GHC] #8230: GHCi 7.6.2 Crashes with GADT + DataKinds

[GHC]

#8230: GHCi 7.6.2 Crashes with GADT + DataKinds
------------------------------------+-------------------------------------
       Reporter:  jozefg            |             Owner:
           Type:  bug               |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  Compiler          |           Version:  7.6.2
       Keywords:  GADT              |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
     Difficulty:  Unknown           |         Test Case:
     Blocked By:                    |          Blocking:
Related Tickets:                    |
------------------------------------+-------------------------------------
 The following snippet caused GHCi to die

     {-# LANGUAGE GADTs, DataKinds #-}
     data A n where
       A :: A 0

 with the following error message

     ghc: panic! (the 'impossible' happened)
       (GHC version 7.6.2 for x86_64-unknown-linux):
         lookupVers2
     <<details unavailable>>
     Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8230>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler