[GHC] #15125: Typeclass instance selection depends on the optimisation level

[GHC]

#15125: Typeclass instance selection depends on the optimisation level
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        Reporter:  nicuveo           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.2.2
      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 simonpj):

 I investigated.  Turns out that this is a near-dup of #14434 -- a bug in
 the "short-cut solver" for type classes.  Happily, it was fixed six months
 ago, and the fix is in 8.4.

 I also agree with comment:4.

 So I'll just close this.  I don't think it's worth a new regression test.

 If anyone reading this has a concrete suggestion for making the user
 manual clearer, please do re-open and off your proposed text.  The user
 manual can always do with improvement!

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15125#comment:5>
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