[GHC] #12507: Can't deduce implicit parameter

[GHC]

#12507: Can't deduce implicit parameter
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        Reporter:  Iceland_jack      |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"cdbc73aea2d8220dc2c3467afbac5c17db96453a/ghc"
 cdbc73ae/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="cdbc73aea2d8220dc2c3467afbac5c17db96453a"
 Test Trac #12507

 This is now working apparently.  It relates to when a
 polymorphic function gets instantiated, under some
 implicit paramter bindings.
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12507#comment:2>
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