[GHC] #13371: instance selection too eager

[GHC]

#13371: instance selection too eager
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           Reporter:  aavogt         |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.0.2
  (Type checker)                     |
           Keywords:                 |  Operating System:  Unknown/Multiple
       Architecture:                 |   Type of failure:  None/Unknown
  Unknown/Multiple                   |
          Test Case:                 |        Blocked By:
           Blocking:                 |   Related Tickets:
Differential Rev(s):                 |         Wiki Page:
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 I see a regression in 8.0.2: the `g_f'` definition is rejected. The error
 goes away if I do one of:

  * -XNoMonoLocalBinds

  * -XNoPolyKinds

  * pasting the inferred type of `g_f`

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13371>
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