[GHC] #13804: MonoLocalBinds/RankNTypes type inference regression in GHC 8.2

[GHC]

#13804: MonoLocalBinds/RankNTypes type inference regression in GHC 8.2
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:
       Component:  Compiler (Type    |              Version:  8.2.1-rc2
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #11698            |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by facundo.dominguez):

 Something odd is going on.

 Adding the type signature {{{sendresult :: Ivory eff ()}}} also makes the
 program compile.

 {{{tct_closed}}} is affected by the use of {{{periph}}} in
 {{{sendresult'}}}. This makes {{{sendresult}}} not closed. But I do not
 understand how this relates to the error message that GHC produces.

 It might be that some use of {{{tct_closed}}} in the type-checker is
 assuming its old meaning.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13804#comment:3>
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