[GHC] #10156: Unable to coerce with flipped Coercible context

[GHC]

#10156: Unable to coerce with flipped Coercible context
-------------------------------------+-------------------------------------
        Reporter:  ekmett            |                   Owner:
            Type:  feature request   |                  Status:  infoneeded
        Priority:  normal            |               Milestone:
       Component:  Compiler (Type    |                 Version:  7.10.1-rc2
  checker)                           |                Keywords:
      Resolution:                    |            Architecture:
Operating System:  Unknown/Multiple  |  Unknown/Multiple
 Type of failure:  None/Unknown      |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by goldfire):

 The following module compiles with 7.10 RC2 on my machine:

 {{{
 module T10156 where

 import Data.Coerce

 data Iso a b = Iso (a -> b) (b -> a)

 coerceIso :: Coercible a b => Iso a b
 coerceIso = Iso coerce coerce
 }}}

 This looks like what you want.

 Is there something I'm missing here?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10156#comment:5>
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