[GHC] #10715: Possible regression in Coercible a (X a) between 7.8 and 7.10

[GHC]

#10715: Possible regression in Coercible a (X a) between 7.8 and 7.10
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        Reporter:  inaki             |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.10.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by simonpj):

 I'm all for !ForeignPtrs having distinct types.  I just don't understand
 why it has to be a recursive type.  What's wrong with this?
 {{{
 newtype FY = FY (ForeignPtr Y)
 data Y
 }}}
 (except that it isn't what c2hs does today)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10715#comment:6>
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