[GHC] #13936: initTc: unsolved constraints

[GHC]

#13936: initTc: unsolved constraints
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        Reporter:  junkbondtrader  |                Owner:  (none)
            Type:  bug             |               Status:  new
        Priority:  normal          |            Milestone:
       Component:  Compiler        |              Version:  8.0.2
      Resolution:                  |             Keywords:
Operating System:  Windows         |         Architecture:  x86_64 (amd64)
 Type of failure:  None/Unknown    |            Test Case:
      Blocked By:                  |             Blocking:
 Related Tickets:                  |  Differential Rev(s):
       Wiki Page:                  |
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Description changed by junkbondtrader:

@@ -19,1 +19,1 @@
- I believe that the function declaration and invocation about don't
+ I believe that the function declaration and invocation above don't

New description:

 {{{
 Prelude> lucky (7.0 :: Num)
 ghc.exe: panic! (the 'impossible' happened)
   (GHC version 8.0.2 for x86_64-unknown-mingw32):
         initTc: unsolved constraints
   WC {wc_insol =
         [W] lucky_afgR :: t_afgQ[tau:1] (CHoleCan: lucky)
         [W] lucky_afhl :: t_afhk[tau:1] (CHoleCan: lucky)}

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

 {{{#!hs
 lucky :: Num -> String
 lucky 7 = "LUCKY NUMBER SEVEN!"
 lucky x = "Sorry, you're out of luck, pal!"
 }}}

 I believe that the function declaration and invocation above don't
 actually make sense, but they caused a panic that asked for a bug report
 so I'm doing it. Apologies for my newness :)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13936#comment:2>
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