[GHC] #12175: Instance resolution regression

[GHC]

#12175: Instance resolution regression
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        Reporter:  crockeea          |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:  8.0.2
       Component:  Compiler          |              Version:  8.0.1
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  GHC rejects       |            Test Case:  indexed-
  valid program                      |  types/should_compile/T12175
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by Ryan Scott <ryan.gl.scott@…>):

 In [changeset:"27f6f388ef1a3cd694008150fe513e3e7be2e6ad/ghc"
 27f6f388/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="27f6f388ef1a3cd694008150fe513e3e7be2e6ad"
 Add regression test for #12648

 Commit ce97b7298d54bdfccd9dcf366a69c5617b4eb43f (the fix for #12175) also
 fixed #12648. Let's add a regression test so that it stays fixed.
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12175#comment:4>
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