[GHC] #14332: Deriving clauses can have forall types

[GHC]

#14332: Deriving clauses can have forall types
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.2.1
  checker)                           |
      Resolution:                    |             Keywords:  deriving
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC accepts       |  Unknown/Multiple
  invalid program                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 > Notice how the k has become * due to kind unification!

 I'd say this is an outright bug.  You should say
 {{{
 data D = D deriving (C Type)
 }}}
 Would you like to open a ticket?

 I grant that it's odd to quantify over a type former.  But it's odd not to
 have ANY way to explicitly quantify.  (Well, I suppose you could use
 standalone deriving.)

 I'm not pressing hard for an explicit forall.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14332#comment:7>
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