[GHC] #14618: Higher rank typechecking is broken

[GHC]

#14618: Higher rank typechecking is broken
-------------------------------------+-------------------------------------
        Reporter:  mniip             |                Owner:  (none)
            Type:  bug               |               Status:  merge
        Priority:  highest           |            Milestone:  8.4.1
       Component:  Compiler (Type    |              Version:  8.2.2
  checker)                           |
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  GHC accepts       |            Test Case:
  invalid program                    |  typecheck/should_fail/T14618
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------
Changes (by goldfire):

 * status:  new => merge
 * testcase:   => typecheck/should_fail/T14618
 * milestone:   => 8.4.1


Comment:

 You can see the commit. It was just a simple oversight in propagating an
 instantiating substitution.

 This should certainly be merged.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14618#comment:6>
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