[GHC] #10381: Type-checking failure with RankNTypes and RebindableSyntax

[GHC]

#10381: Type-checking failure with RankNTypes and RebindableSyntax
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        Reporter:  goldfire          |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
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Comment (by shachaf):

 I can't test the code right now, but I'd expect `do { bar <- foo; return
 bar }` to mean `let { ok bar = return bar; ok _ = fail "..." } in foo >>=
 ok` as specified in the report. That could probably have rank-2 problems
 where a lambda doesn't.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10381#comment:1>
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