[GHC] #11698: GHC's tct_closed flag is not being set correctly

[GHC]

#11698: GHC's tct_closed flag is not being set correctly
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        Reporter:  simonpj           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:  11656
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 Yes for (a). And (c) is implied by (a) and (b).  Why?  Assume (induction
 hypothesis) that closed variables have closed types, and that we have a
 new binding f = e, satisfying (a) and (b).

 Then since monomorphism restriction does not apply, and there are no free
 type variables, we can fully generalise, so its type will be closed.  We
 should state that in the Note though

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11698#comment:4>
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