[GHC] #14524: Use sortOn instead of sortWith

[GHC]

#14524: Use sortOn instead of sortWith
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        Reporter:  AndreasK          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by nomeata):

 `SortOn` is there since 4.8, which, according to
 https://ghc.haskell.org/trac/ghc/wiki/Commentary/Libraries/VersionHistory
 corresponds to GHC-7.10.1 – oh yes, this is definitely around for long
 enough. A differential revision with that change is will probably be well-
 received.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14524#comment:1>
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