[GHC] #7153: GHC crashes with "(Array.!): undefined array element" while building

[GHC]

#7153: GHC crashes with "(Array.!): undefined array element" while building
---------------------------------+------------------------------------------
    Reporter:  tibbe             |       Owner:                  
        Type:  bug               |      Status:  new             
    Priority:  highest           |   Milestone:  7.6.1           
   Component:  Compiler          |     Version:  7.6.1-rc1       
    Keywords:                    |          Os:  Unknown/Multiple
Architecture:  Unknown/Multiple  |     Failure:  None/Unknown    
  Difficulty:  Unknown           |    Testcase:                  
   Blockedby:                    |    Blocking:                  
     Related:                    |  
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Comment(by tibbe):

 Replying to [comment:3 igloo]:
 > Does the builder always start from a clean directory, i.e. no old `.hi`
 files etc?

 It does a `cabal clean` before building, but since Cabal first compiles a
 Setup.hs in-place (i.e. not using `dist/` as the output directory) there
 might be old `.hi` files lying around from the previous compiler version.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7153#comment:4>
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