[GHC] #8969: GHCi crash on invalid input

[GHC]

#8969: GHCi crash on invalid input
------------------------------------+-------------------------------------
       Reporter:  aslpavel          |             Owner:
           Type:  bug               |            Status:  new
       Priority:  normal            |         Milestone:
      Component:  Compiler          |           Version:  7.6.3
       Keywords:                    |  Operating System:  Unknown/Multiple
   Architecture:  Unknown/Multiple  |   Type of failure:  GHCi crash
     Difficulty:  Unknown           |         Test Case:
     Blocked By:                    |          Blocking:
Related Tickets:                    |
------------------------------------+-------------------------------------
 I know its incorrect haskell code but after entering following sequence of
 commands, ghci seems to be crashing.

 {{{
 GHCi, version 7.6.3: http://www.haskell.org/ghc/  :? for help
 Loading package ghc-prim ... linking ... done.
 Loading package integer-gmp ... linking ... done.
 Loading package base ... linking ... done.
  λ > data R = R { x1 :: Int, x2 :: Int, x3 :: Int } deriving Show
  λ > data R a = State { x1 :: Int, x2 :: Int, x3 :: Int } a
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.6.3 for x86_64-unknown-linux):
         tc_hs_type: record

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

 I hope it would be helpful. Thanks!

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8969>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler