[GHC] #13600: surprising error message with bang pattern

[GHC]

#13600: surprising error message with bang pattern
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        Reporter:  andrewufrank      |                Owner:  v0d1ch
            Type:  bug               |               Status:  patch
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.2
      Resolution:                    |             Keywords:  BangPatterns,
                                     |  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #15166, #15458    |  Differential Rev(s):  Phab:D5040
       Wiki Page:                    |
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Comment (by v0d1ch):

 Thank you for the additional information! I am currently digging trough
 parser trying to find a place where this check should be added.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13600#comment:13>
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