[GHC] #13719: checkFamInstConsistency dominates compile time

[GHC]

#13719: checkFamInstConsistency dominates compile time
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        Reporter:  niteria           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler (Type    |              Version:  8.3
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #13092, #13099,   |  Differential Rev(s):  phab:D3600,
  #12191                             |  phab:D3602
       Wiki Page:                    |
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Comment (by Ben Gamari <ben@…>):

 In [changeset:"2bc3a0570dac333cc7fb6f8038e08f36d62e4d13/ghc"
 2bc3a057/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="2bc3a0570dac333cc7fb6f8038e08f36d62e4d13"
 Testcase for type family consistency checks

 Based on my quick search, we don't have a test
 that verifies that we check the type family instances of
 currently compiled module against direct or indirect
 dependencies.

 This adds two tests: for a direct dependency and
 for an indirect dependency.

 I also added a comment to make it clear what the 'Over'
 test tests.

 Other than completeness, it makes sense to have these
 tests because if you look at
 Note [The type family instance consistency story] in FamInsts
 these cases are checked through different mechanisms.

 Test Plan: new tests

 Reviewers: simonmar, rwbarton, simonpj, austin, bgamari

 Reviewed By: simonpj, bgamari

 Subscribers: thomie

 GHC Trac Issues: #13719

 Differential Revision: https://phabricator.haskell.org/D3602
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13719#comment:5>
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