[GHC] #10429: GHC fails to import instance

[GHC]

#10429: GHC fails to import instance
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        Reporter:  crockeea          |                   Owner:
            Type:  bug               |                  Status:  closed
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:  invalid           |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Changes (by rwbarton):

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


Comment:

 You have two versions of `transformers` installed under 7.10. See
 http://www.yesodweb.com/blog/2014/09/woes-multiple-package-versions or
 search Google for "No instance for MonadTrans" for more information.

 Also see #9611 about improving the error message in this case.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10429#comment:1>
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