[GHC] #13333: Typeable regression in GHC HEAD

[GHC]

#13333: Typeable regression in GHC HEAD
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  goldfire
            Type:  bug               |               Status:  patch
        Priority:  highest           |            Milestone:  8.2.1
       Component:  Compiler (Type    |              Version:  8.1
  checker)                           |             Keywords:  typeable,
      Resolution:                    |  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):  Phab:D3424
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by Ben Gamari <ben@…>):

 In [changeset:"09bf135ace55ce2572bf4168124d631e386c64bb/ghc"
 09bf135a/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="09bf135ace55ce2572bf4168124d631e386c64bb"
 Fix #13333 by fixing the covar's type in ctEvCoercion

 The change is noted in Note [Given in ctEvCoercion]. This patch
 also adds a bit more commentary to TcFlatten, documenting some
 key invariants of the flattening algorithm. While in the area,
 I also removed some stale commentary from TcCanonical.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13333#comment:16>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler