[GHC] #14438: Using a (meaningless) generic currency sign (¤) instead of $ causes panicing

[GHC]

#14438: Using a (meaningless) generic currency sign (¤) instead of $ causes
panicing
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           Reporter:  Izmaki          |             Owner:  (none)
               Type:  bug             |            Status:  new
           Priority:  low             |         Milestone:
          Component:  GHCi            |           Version:  8.0.2
           Keywords:  ¤               |  Operating System:  Linux
       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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 The following two lines of HS produces the reported error. It was actually
 a mistype and probably not that serious, but I was told to report it.

 The issue is combining the "generic currency" symbol ¤ with the Integral
 constraint (using e.g. Integer instead as the constraint does not produce
 the same error).

 {{{#!hs
 Prelude> let ones x = snd $ divMod x 10
 Prelude> ones ¤ (5 :: Integral)
 ghc: panic! (the 'impossible' happened)
   (GHC version 8.0.2 for x86_64-unknown-linux):
         initTc: unsolved constraints
   WC {wc_insol =
         [W] ¤_a2l9 :: t_a2l8[tau:1] (CHoleCan: ¤)
         [W] ¤_a2lJ :: t_a2lI[tau:1] (CHoleCan: ¤)}

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

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14438>
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