[GHC] #10614: Show constraints in ``Found hole...''

[GHC]

#10614: Show constraints in ``Found hole...''
-------------------------------------+-------------------------------------
        Reporter:  bjmprice          |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.1
      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:                    |
-------------------------------------+-------------------------------------

Comment (by Iceland_jack):

 Replying to [comment:3 zyla]:
 > +1 for class constraints. This comes up a lot when working with
 existentials. Consider this (contrived) example:
 +1 not so contrived, I have encountered it and more complex examples

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10614#comment:4>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler