[GHC] #13658: Assertion failure on HEAD: "optCoercion changed types!"

[GHC]

#13658: Assertion failure on HEAD: "optCoercion changed types!"
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        Reporter:  bgamari           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by slyfox):

 I've added a bit of debug into ASSERT. The complain is about type mismatch
 between in_ty1, out_ty1:
 {{{
   in_ty1:
     base:Data.Typeable.Internal.TypeRep{tc 35W}
       (ghc-prim:GHC.Types.Any{(w) tc 35K}
          ghc-prim:GHC.Types.Any{(w) tc 35K})

   out_ty1:
     base:Data.Typeable.Internal.TypeRep{tc 35W}
       ghc-prim:GHC.Types.Any{(w) tc 35K}
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13658#comment:1>
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