[GHC] #9587: Type checking with type functions introduces many type variables, which remain ambiguous. The code no longer type checks.

[GHC]

#9587: Type checking with type functions introduces many type variables, which
remain ambiguous. The code no longer type checks.
-------------------------------------+-------------------------------------
        Reporter:  oleg              |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  7.8.3
  checker)                           |             Keywords:  TypeFamilies,
      Resolution:                    |  ambiguity check
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #9607             |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by RyanGlScott):

 * keywords:  type family, ambiguity check => TypeFamilies, ambiguity check


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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9587#comment:13>
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