[GHC] #13524: GHC does not preserve order of forall'd vars with TypeApplications

[GHC]

#13524: GHC does not preserve order of forall'd vars with TypeApplications
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        Reporter:  crockeea          |                Owner:  (none)
            Type:  bug               |               Status:  closed
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.2
      Resolution:  fixed             |             Keywords:
                                     |  TypeApplications
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  GHC rejects       |            Test Case:
  valid program                      |  typecheck/should_compile/T13524
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by simonpj):

 * status:  new => closed
 * testcase:   => typecheck/should_compile/T13524
 * resolution:   => fixed


Comment:

 I fixed this, somewhat by accident. The key code is in
 `TcSimplify.decideQuantifiedTyVars`, where there is a comment to explain.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13524#comment:13>
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