[GHC] #12936: Type inference regression in GHC HEAD

[GHC]

#12936: Type inference regression in GHC HEAD
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        Reporter:  RyanGlScott       |                Owner:
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.2.1
       Component:  Compiler (Type    |              Version:  8.1
  checker)                           |
      Resolution:                    |             Keywords:
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:                    |
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Changes (by RyanGlScott):

 * cc: simonpj (added)


Comment:

 Simon, this bug was introduced in
 https://git.haskell.org/ghc.git/commit/f8c966c70bf4e6ca7482658d4eaca2dae367213f.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12936#comment:1>
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