[GHC] #6060: the 'impossible' happened

[GHC]

#6060: the 'impossible' happened
------------------------------+---------------------------------------------
 Reporter:  lerkok            |          Owner:                  
     Type:  bug               |         Status:  new             
 Priority:  normal            |      Component:  Compiler        
  Version:  7.4.1             |       Keywords:                  
       Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
  Failure:  None/Unknown      |       Testcase:                  
Blockedby:                    |       Blocking:                  
  Related:                    |  
------------------------------+---------------------------------------------
 {{{
 $ cat bug.hs
 foo = do let bad = [True | x <- [] | y <- []]
 $ ghc bug.hs
 [1 of 1] Compiling Main             ( bug.hs, bug.o )

 bug.hs:1:10:ghc: panic! (the 'impossible' happened)
   (GHC version 7.4.1 for x86_64-apple-darwin):
         Prelude.undefined
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6060>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler