[GHC] #14824: automatically select instance

[GHC]

#14824: automatically select instance
-------------------------------------+-------------------------------------
           Reporter:  zaoqi          |             Owner:  (none)
               Type:  feature        |            Status:  new
  request                            |
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.2.2
           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:
-------------------------------------+-------------------------------------
 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.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14824>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler