[GHC] #11186: Give strong preference to type variable names in scope when reporting hole contexts

[GHC]

#11186: Give strong preference to type variable names in scope when reporting hole
contexts
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        Reporter:  dfeuer            |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  7.10.2
  checker)                           |
      Resolution:                    |             Keywords:  typed-holes
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 dfeuer):

 It looks like it may be preferring the name of the type variable used in
 the GADT definition to the one in the pattern, which seems very wrong to
 me.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11186#comment:3>
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