[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:  new
        Priority:  high              |               Milestone:  7.10.2
       Component:  Compiler (Type    |                 Version:  7.10.1-rc1
  checker)                           |                Keywords:
      Resolution:                    |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  GHC rejects       |               Test Case:
  valid program                      |                Blocking:
      Blocked By:                    |  Differential Revisions:
 Related Tickets:  #10226            |
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Comment (by rwbarton):

 Replying to [comment:29 jeltsch]:
 > Is this code accepted by GHC HEAD?

 Yes, though it also gives a warning about a redundant constraint `G (F a)
 ~ a`...

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10009#comment:31>
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