[GHC] #11583: Make warning names more consistent

[GHC]

#11583: Make warning names more consistent
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        Reporter:  bgamari           |                Owner:
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by svenpanne):

 Hmmm, can we have a fix for this ''before'' the final 8.0.1 comes out?
 Otherwise things are a bit chaotic: We introduce the new -W form (and new
 warnings), only to have some of those -Wfoo renamed immediately
 afterwards, leading to even more CPP magic in projects. The short form of
 the changes, just for reference:

   * Use "sigs" or "signatures" consistently (doesn't really matter which
 one)

    * Use "pattern-synonyms", not "pat-syn"

 Currently e.g. the `half` package doesn't work with the GHC 8 series
 because of the ad-hoc naming changes of `-fno-warn-missing-pat-syn-sigs`
 (which is called `-Wno-missing-pat-syn-signatures` currently, but will be
 `-Wno-missing-pattern-synonym-signatures` or `-Wno-missing-pattern-
 synonym-sigs`, who knows...?).

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11583#comment:3>
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