[GHC] #12594: DeriveAnyClass fails to derive some classes

[GHC]

#12594: DeriveAnyClass fails to derive some classes
-------------------------------------+-------------------------------------
        Reporter:  ivanm             |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      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 simonpj):

 Yes, documenting this better would be a Jollly Good Thing.

 Also pointing out that if the (necessarily fallible) heuristic for
 deducing a context fails, you can always us a "standalone deriving"
 declaration to specify the context yourself; it's a bit like adding a type
 signature.

 Ryan or someone -- would you like to suggest a documentation patch?

 Simon

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12594#comment:3>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler