[GHC] #9160: Panic: Template variable unbound in rewrite rule

[GHC]

#9160: Panic: Template variable unbound in rewrite rule
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       Reporter:  mietek          |             Owner:
           Type:  bug             |            Status:  new
       Priority:  normal          |         Milestone:
      Component:  Compiler        |           Version:  7.8.2
       Keywords:                  |  Operating System:  MacOS X
   Architecture:  x86_64 (amd64)  |   Type of failure:  Compile-time crash
     Difficulty:  Unknown         |         Test Case:
     Blocked By:                  |          Blocking:
Related Tickets:                  |
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 Installing `singletons-1.0` with GHC 7.8.2 on OS X 10.9.2 fails:

 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.8.2 for x86_64-apple-darwin):
         Template variable unbound in rewrite rule
 }}}

 Full build log attached.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9160>
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