[GHC] #7736: Parallel array enumeration causes compiler panic (enumFromToP)

[GHC]

#7736: Parallel array enumeration causes compiler panic (enumFromToP)
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              Reporter:              |            Owner:  chak
  amosrobinson                       |           Status:  new
                  Type:  bug         |        Milestone:  7.10.1
              Priority:  normal      |          Version:  7.7
             Component:  Compiler    |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:  Compile-    |  Related Tickets:  #7078
  time crash                         |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by thomie):

 Smaller testcase:

 {{{
 $ cat EnumFromToP.hs
 {-# LANGUAGE ParallelArrays #-}
 module EnumFromToP where
 nums = [: 0 .. 100 :]

 $ ghc-7.9.20141121 EnumFromToP.hs
 [1 of 1] Compiling EnumFromToP      ( EnumFromToP.hs, EnumFromToP.o )
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.9.20141121 for x86_64-unknown-linux):
         DsMonad: uninitialised ds_parr_bi
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7736#comment:7>
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