[GHC] #10598: DeriveAnyClass and GND don't work well together

[GHC]

#10598: DeriveAnyClass and GND don't work well together
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        Reporter:  osa1              |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.11
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  None/Unknown      |  Unknown/Multiple
      Blocked By:                    |               Test Case:
 Related Tickets:                    |                Blocking:
                                     |  Differential Revisions:
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Comment (by simonpj):

 Usually the MINIMAL thing means "you must give non-default definitions for
 at least these methods".  That's easy to understand in the absence of
 generic-default methods, because the normal (or polymorphic) default
 methods invariably work by invoking other methods in the same class or
 superclass.

 But given generic-default methods, it's not so clear to me.  I suspect
 that MINIMAL should ''not'' complain if you fail to give explicit code for
 a method that has a generic default, because the generic default is
 capable of doing type-specific stuff.  (I have not checked what really
 happens.)

 The manual entry for MINIMAL does not cover this, and it jolly well
 should.

 Once that is nailed down, it'll become clear what to do for
 `DeriveAnyClass`, I think.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10598#comment:11>
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