[GHC] #7401: Can't derive instance for Eq when datatype has no constructor, while it is trivial do do so.

[GHC]

#7401: Can't derive instance for Eq when datatype has no constructor, while it is
trivial do do so.
-------------------------------------+-------------------------------------
        Reporter:  jpbernardy        |                Owner:  (none)
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.6.1
      Resolution:                    |             Keywords:  deriving,
                                     |  newcomer
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #10577, #13117    |  Differential Rev(s):  Phab:D978
       Wiki Page:                    |
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Comment (by AntC):

 Now a github proposal https://github.com/ghc-proposals/ghc-
 proposals/pull/63, see discussion.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7401#comment:51>
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