[GHC] #16281: PatternSynonyms doesn't accept non-prenex quantified functions, doesn't float foralls

[GHC]

#16281: PatternSynonyms doesn't accept non-prenex quantified functions, doesn't
float foralls
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        Reporter:  Iceland_jack      |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.7
      Resolution:                    |             Keywords:
                                     |  PatternSynonyms
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 goldfire):

 The problem is that the thing after the `::` in `pattern Blah ::` is not a
 type. It's a type-like thing, with requireds, universals, provideds,
 existentials, arguments, and a result, all arranged using familiar
 notation. Perhaps someday, we'll generalize this, allowing type variables
 to appear in arbitrary positions within the type (maybe someone wants an
 existential ''before'' a universal, for example), but this is a largish
 design problem.

 I'm inclined to "wontfix" for this one, leaving it for a ghc-proposal to
 flesh out all the details of the new design.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16281#comment:1>
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