[GHC] #13234: Yesod and Persistent cause compiler panic

[GHC]

#13234: Yesod and Persistent cause compiler panic
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           Reporter:  cheshircat        |             Owner:
               Type:  bug               |            Status:  new
           Priority:  normal            |         Milestone:
          Component:  Compiler          |           Version:  8.0.2
           Keywords:                    |  Operating System:  Linux
       Architecture:  Unknown/Multiple  |   Type of failure:  None/Unknown
          Test Case:                    |        Blocked By:
           Blocking:                    |   Related Tickets:
Differential Rev(s):                    |         Wiki Page:
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 Hello,

 This is my first bug report for GHC, so excuse me if I don't have all the
 formatting correct, and please tell me how to correct it!

 I am working on a yesod app, and upon running cabal run, I got this
 message:

 {{{#!hs
 Preprocessing executable 'creative-index-org' for creative-index-
 org-0.0.0...
 [1 of 1] Compiling Main             ( Main.hs, dist/build/creative-index-
 org/creative-index-org-tmp/Main.o )

 <no location info>: error:
     ghc: panic! (the 'impossible' happened)
   (GHC version 8.0.2 for x86_64-unknown-linux):
         initTc: unsolved constraints
   WC {wc_insol = [W] person_aodw :: t_aodv[tau:1] (CHoleCan: person)}

 Please report this as a GHC bug:  http://www.haskell.org/ghc/reportabug
 }}}

 I have attached Main.hs, the cabal file, and a nix-shell file (in case you
 use nix) that contains the environment I was running this in.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13234>
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