[GHC] #12014: Make it possible to deprecate a method instantiation of a typeclass instance

[GHC]

#12014: Make it possible to deprecate a method instantiation of a typeclass
instance
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        Reporter:  niteria           |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:
      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:                    |
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Comment (by niteria):

 I was able to solve my use case from the description by using `-fdefer-
 type-errors`. Not having an `Ord` instance is a type error, so I removed
 the `Ord Unique` instance and compiled with `-fdefer-type-errors`.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12014#comment:6>
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