[GHC] #14824: automatically select instance

[GHC]

#14824: automatically select instance
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        Reporter:  zaoqi             |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       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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Description changed by zaoqi:

Old description:

> There is
> {{{#!hs
> class C a b where m :: [a] -> b
> instance C x0 x0
> instance C x1 x2
> instance C x0 x3
> }}}
> x0 x1 x2 x3 is Types.
> FunctionalDependencies can't work.

New description:

 There is
 {{{#!hs
 class C a b where m :: [a] -> b
 instance C x0 x0
 instance C x1 x2
 instance C x0 x3
 }}}
 x0 x1 x2 x3 are Types.
 FunctionalDependencies can't work.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14824#comment:1>
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