[GHC] #10782: Existential variables not scoped?

[GHC]

#10782: Existential variables not scoped?
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        Reporter:  goldfire          |                   Owner:
            Type:  bug               |                  Status:  closed
        Priority:  normal            |               Milestone:
       Component:  Compiler (Type    |                 Version:  7.11
  checker)                           |
      Resolution:  invalid           |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Changes (by goldfire):

 * status:  new => closed
 * resolution:   => invalid


Comment:

 Ah. After quite a bit more staring at the situation, I now understand.

 Existential variables are ''not'' added to `tcl_tyvars` directly. But all
 free variables of anything that is in scope (term-level or type-level)
 ''are'' added there. Because you can't ever get to a type variable unless
 it is in scope or something that mentions it is in scope, this is all OK.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10782#comment:2>
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