[GHC] #11462: Use of typechecker plugin erroneously triggers "unbound implicit parameter" error

[GHC]

#11462: Use of typechecker plugin erroneously triggers "unbound implicit parameter"
error
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        Reporter:  kwf               |                Owner:
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler (Type    |              Version:  8.0.1-rc1
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by thomie):

 * cc: gridaphobe (added)
 * priority:  high => highest
 * version:  7.10.3 => 8.0.1-rc1


Comment:

 Thank you for reducing the problem to this simple testcase.

 This is a regression from ghc-7.10.3.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11462#comment:1>
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