[GHC] #12919: Equality not used for substitution

[GHC]

#12919: Equality not used for substitution
-------------------------------------+-------------------------------------
        Reporter:  int-index         |                Owner:  goldfire
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:
       Component:  Compiler (Type    |              Version:  8.0.1
  checker)                           |
      Resolution:                    |             Keywords:  TypeInType
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  GHC rejects       |  Unknown/Multiple
  valid program                      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"41ec722d71db0eadeddd582a23aab7347349185f/ghc"
 41ec722d/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="41ec722d71db0eadeddd582a23aab7347349185f"
 Test Trac #12919

 Test Plan: make test TEST=T12919

 Reviewers: bgamari, austin

 Reviewed By: bgamari

 Subscribers: thomie

 Differential Revision: https://phabricator.haskell.org/D2788

 GHC Trac Issues: #12919
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12919#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler