[GHC] #10845: Incorrect behavior when let binding implicit CallStack object

[GHC]

#10845: Incorrect behavior when let binding implicit CallStack object
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        Reporter:  nitromaster101    |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.11
      Resolution:                    |                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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Comment (by gridaphobe):

 Hmm, it looks like the `?loc` constraint in `f` is being solved in an
 environment that doesn't include the given `?loc` from the function's
 context. Very strange, and certainly incorrect.

 Thanks for the report!

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10845#comment:3>
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