[GHC] #13593: Unexpected behavior from Data.List.groupBy

[GHC]

#13593: Unexpected behavior from Data.List.groupBy
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        Reporter:  dsf               |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Core Libraries    |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Documentation     |  Unknown/Multiple
  bug                                |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by dsf):

 Yes, the Haskell report does contain this specification.  I'm just trying
 to improve the documentation which is typically used by someone who is in
 the process of building Haskell code and is perhaps somewhat removed (at
 that moment) from the design decisions discussed in the Haskell report.  I
 have found that the requirements of the reference documentation used while
 writing code is very different from those of the documents defining the
 language.  The name and signature of groupBy give the impression that what
 I tried to do above would work, so I'm assuming that my mistake and
 consequent loss of time might be one that others would also make.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13593#comment:10>
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