[GHC] #4896: Deriving Data does not work for attached code

[GHC]

#4896: Deriving Data does not work for attached code
-------------------------------------+-------------------------------------
              Reporter:  mitar       |            Owner:
                  Type:  bug         |           Status:  infoneeded
              Priority:  low         |        Milestone:  7.10.1
             Component:  Compiler    |          Version:  7.1
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:
             Test Case:              |
  deriving/should_compile/T4896      |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------
Changes (by simonpj):

 * cc: dreixel (added)
 * testcase:   => deriving/should_compile/T4896


Comment:

 The error message for mojojojo is exactly right.

 The error message from HEAD for the original example is actually a long-
 standing bug; quite a different one from the one originally reported. This
 code should compile.

 Good catch, thank you Tomie!  Patch coming.

 Pedro, can you just check that I have done this right?

 Simon

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4896#comment:10>
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