[GHC] #9173: Better type error messages

[GHC]

#9173: Better type error messages
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        Reporter:  simonpj           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.8.2
      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 goldfire):

 The information needed in !TcErrors to address this ticket is now very
 much to hand, in the `uo_thing` field of a `TypeEqOrigin`. There is some
 refactoring to do to improve the plumbing, but it would now be easy for
 someone to take an honest stab at this ticket.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9173#comment:18>
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