[GHC] #9692: Template Haskell reification for Data Families is buggy?

[GHC]

#9692: Template Haskell reification for Data Families is buggy?
-------------------------------------+-------------------------------------
              Reporter:  hpacheco    |            Owner:  goldfire
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Template    |          Version:  7.8.3
  Haskell                            |         Keywords:  TemplateHaskell
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:  MacOS X     |       Difficulty:  Easy (less than 1
       Type of failure:              |  hour)
  None/Unknown                       |       Blocked By:
             Test Case:              |  Related Tickets:
              Blocking:              |
Differential Revisions:  Phab:D355   |
-------------------------------------+-------------------------------------

Comment (by Richard Eisenberg <eir@…>):

 In [changeset:"e319d6d2704edc2696f47409f85f4d4ce58a6cc4/ghc"]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="e319d6d2704edc2696f47409f85f4d4ce58a6cc4"
 Reify data family instances correctly.

 Summary:
 Fix #9692.

 The reifier didn't account for the possibility that data/newtype
 instances are sometimes eta-reduced. It now eta-expands as necessary.

 Test Plan: th/T9692

 Reviewers: simonpj, austin

 Subscribers: thomie, carter, ezyang, simonmar

 Differential Revision: https://phabricator.haskell.org/D355
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9692#comment:6>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler