[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 goldfire):

 In both of your examples, IIUC, the unification happens to the datatype
 variables, not the newly-quantified variables in the `deriving` clause. I
 agree that this kind unification is good. I further agree that any
 unwritten kinds in a `deriving` clause should be unified. But I think any
 explicitly written kinds are skolems, and that this doesn't cause
 problems.

 The example toward the end of comment:8 should be rejected; the user
 should have to write `Type`, not `k`.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14332#comment:9>
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