[GHC] #8668: SPECIALIZE silently fails to apply

[GHC]

#8668: SPECIALIZE silently fails to apply
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        Reporter:  crockeea          |            Owner:
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  Compiler          |          Version:  7.6.2
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  x86_64 (amd64)
 Type of failure:  None/Unknown      |       Difficulty:  Unknown
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by crockeea):

 Replying to [comment:15 carter]:
 > could you walk me through why
 > {{{
 > {-# SPECIALIZE plusFastCyc :: (FastCyc (VT U.Vector m) Int) -> (FastCyc
 (VT U.Vector m) Int) -> (FastCyc (VT U.Vector m) Int) #-}
 > }}}
 > isn't satisfactory?

 I added some more code to demonstrate something more like a real use case
 for the program: http://lpaste.net/98840. It has the same issue as
 `Foo.hs` above, but hopefully you can see why the constraint is needed. I
 wanted to remove it from the example to show that the problem wasn't type
 families, constraint kinds, etc.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8668#comment:17>
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