[GHC] #14288: ScopedTypeVariables with nested foralls broken since 8.0.2

[GHC]

#14288: ScopedTypeVariables with nested foralls broken since 8.0.2
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        Reporter:  MikolajKonarski   |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.2.1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Linux             |         Architecture:  x86_64
 Type of failure:  GHC rejects       |  (amd64)
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by goldfire):

 What do you think of

 {{{#!hs
 f :: forall a. a -> Int -> forall b. (a, b)
 f x = const (x, undefined :: b)
 }}}

 Note that the quantifier for `b` hasn't been encountered in the term
 definition, which takes only one argument. Accepting this would be
 strange, indeed, in my view.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14288#comment:8>
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