[GHC] #10009: type inference regression when faking injective type families

[GHC]

#10009: type inference regression when faking injective type families
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        Reporter:  aavogt            |                   Owner:
            Type:  bug               |                  Status:  closed
        Priority:  high              |               Milestone:  7.10.1
       Component:  Compiler (Type    |                 Version:  7.10.1-rc1
  checker)                           |                Keywords:
      Resolution:  worksforme        |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  GHC rejects       |               Test Case:
  valid program                      |                Blocking:
      Blocked By:                    |  Differential Revisions:
 Related Tickets:                    |
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Changes (by dfeuer):

 * status:  new => closed
 * resolution:   => worksforme


Comment:

 I just tested with 7.11.20150103 and I couldn't reproduce the problem. I
 tried

 {{{
   where a = f (undefined :: F a) :: a
   where a :: a = f (undefined :: F a)
      --and also
   where a :: a
         a = f (undefined :: F a)
 }}}

 so unless there's some code missing from this example, it's been fixed.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10009#comment:2>
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