[GHC] #4175: GHCi support for type/data families should match that of related features

[GHC]

#4175: GHCi support for type/data families should match that of related features
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        Reporter:  claus               |            Owner:
            Type:  bug                 |           Status:  closed
        Priority:  low                 |        Milestone:  7.6.2
       Component:  GHCi                |          Version:  6.12.3
      Resolution:  fixed               |         Keywords:  FD TF
Operating System:  Unknown/Multiple    |     Architecture:
 Type of failure:  None/Unknown        |  Unknown/Multiple
       Test Case:  ghci/scripts/T4175  |       Difficulty:  Unknown
        Blocking:                      |       Blocked By:
                                       |  Related Tickets:
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Comment (by Patrick Palka <patrick@…>):

 In [changeset:"eb8fb434ff5e962a54247cacc5d3340972d5daf4/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="eb8fb434ff5e962a54247cacc5d3340972d5daf4"
 Simplify and improve coverage of ":info" instance lookup

 During instance lookup, we can treat classes and data families like any
 other TyCon instead of special-casing them.  This approach, aside from
 being simpler, has the benefit of returning extra relevant instances for
 classes and data families.  For example, given

 class A a
 instance B (a :: Constraint)
 instance A B

 ":info B" will now also print "instance A B" where previously it didn't
 due to the special casing of class TyCons in lookupInsts.

 This improves upon the existing patch for Trac #4175
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4175#comment:13>
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