[GHC] #11551: Get doctests into testsuite

[GHC]

#11551: Get doctests into testsuite
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        Reporter:  lwm               |                Owner:
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Core Libraries    |              Version:  7.10.3
      Resolution:                    |             Keywords:
                                     |  documentation, doctest
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Documentation     |  Unknown/Multiple
  bug                                |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by phadej):

 With https://gist.github.com/phadej/fdd74f4b4b40dc0a758ca6192cd66e83 I can
 successfully run the doctests in `base`. There's a hack, it picks files
 based on whether there is `$setup`, which IMHO is not so bad assumption.

 If someone could give a pointer how to integrate it with `validate`, I
 probably can do it. Yet, i'd like to have ability to run the doctests in
 standalone way, as editing docs / doctests shouldn't require rebuilds of
 the `base` etc.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11551#comment:6>
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