[GHC] #9515: Deprecate -XExplicitForAll

[GHC]

#9515: Deprecate -XExplicitForAll
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              Reporter:  dfeuer      |            Owner:
                  Type:  feature     |           Status:  new
  request                            |        Milestone:
              Priority:  normal      |          Version:  7.8.3
             Component:  Compiler    |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:              |  Related Tickets:
  None/Unknown                       |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by rwbarton):

 FWIW I don't regard `ScopedTypeVariables` as changing the semantics of
 `forall`. Rather it changes the meaning of type variables in type
 ascriptions and non-top-level type declarations depending on whether those
 variables were mentioned in a particular syntactic form involving
 `forall`. As such I don't experience any cognitive dissonance when
 thinking about ExplicitForall, RankNTypes, ScopedTypeVariables, and their
 various combinations.

 I realize that this is a subtle distinction and that `ScopedTypeVariables`
 is often described as bestowing a special new meaning on the keyword
 `forall`.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9515#comment:14>
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