[GHC] #11715: Constraint vs *

[GHC]

#11715: Constraint vs *
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        Reporter:  bgamari           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.2.1
       Component:  Compiler (Type    |              Version:  8.0.1-rc1
  checker)                           |
      Resolution:                    |             Keywords:  Typeable
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 int-index):

 At definition site `F a` cannot satisfy the `a =>` constraint unless `F a
 ~ a` is also in scope (it's not), so there's no ambiguity here.

 The way I see it, when you instantiate `a` with `Int`, instance resolution
 is already done. Is this not the case?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11715#comment:21>
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