[GHC] #14273: Typed holes are oblivious to type class constraints

[GHC]

#14273: Typed holes are oblivious to type class constraints
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.3
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Poor/confusing    |  Unknown/Multiple
  error message                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by RyanGlScott):

 Replying to [comment:1 mpickering]:
 > Perhaps also the type of `pleaseShow` in the relevant bindings lacks the
 constraint on `a`?

 Ah, right you are. The error states:

 {{{
     • Relevant bindings include
         a :: a (bound at Bug.hs:3:17)
         pleaseShow :: Bool -> a -> Maybe String (bound at Bug.hs:2:1)
 }}}

 But that second binding really ought to be `pleaseShow :: Show a => Bool
 -> a -> Maybe String`, no?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14273#comment:2>
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