[GHC] #8066: Compiler Panic When Using Instance Derivation With Singletons

[GHC]

#8066: Compiler Panic When Using Instance Derivation With Singletons
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        Reporter:  tvynr               |            Owner:
            Type:  bug                 |           Status:  new
        Priority:  normal              |        Milestone:
       Component:  Compiler            |          Version:  7.6.3
      Resolution:                      |         Keywords:
Operating System:  Unknown/Multiple    |     Architecture:
 Type of failure:  Compile-time crash  |  Unknown/Multiple
       Test Case:                      |       Difficulty:  Unknown
        Blocking:                      |       Blocked By:
                                       |  Related Tickets:
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Comment (by tvynr):

 That looks great, thanks.  :)  And for anyone else who encounters this
 problem or is perhaps about as confused by the TypeLits stuff as I am,
 adding the following fixes the panic in GHC 7.6.1 (and leads to revealing
 mistakes in the anyVar function):

 {{{
 instance SingE (Kind :: QualForm) QualForm where
   fromSing x = case x of
     UnqualifiedTVarS -> UnqualifiedTVar
     QualifiedTVarS -> QualifiedTVar
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8066#comment:3>
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