[GHC] #4921: report ambiguous type variables more consistently

[GHC]

#4921: report ambiguous type variables more consistently
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              Reporter:  Saizan      |            Owner:
                  Type:  feature     |           Status:  new
  request                            |        Milestone:  7.10.1
              Priority:  low         |          Version:  7.0.1
             Component:  Compiler    |         Keywords:
  (Type checker)                     |     Architecture:  Unknown/Multiple
            Resolution:              |       Difficulty:  Unknown
      Operating System:              |       Blocked By:
  Unknown/Multiple                   |  Related Tickets:
       Type of failure:              |
  None/Unknown                       |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"30d260586d46466419b109057ec87d4f097331a1/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="30d260586d46466419b109057ec87d4f097331a1"
 Test Trac #4921
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4921#comment:6>
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