[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:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.2
      Resolution:                    |             Keywords:
                                     |  TypeApplications
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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Comment (by Simon Peyton Jones <simonpj@…>):

 In [changeset:"0ae72512255ba66ef89bdfeea65a23ea6eb35124/ghc"
 0ae72512/ghc]:
 {{{
 #!CommitTicketReference repository="ghc"
 revision="0ae72512255ba66ef89bdfeea65a23ea6eb35124"
 Yet more work on TcSimplify.simplifyInfer

 The proximate cause for this patch is Trac #13482, which pointed out
 further subtle interactions between
    - Inferring the most general type of a function
    - A partial type signature for that function

 That led me into /further/ changes to the shiny new stuff in
 TcSimplify.simplifyInfer, decideQuantification, decideMonoTyVars,
 and related functions.

 Happily, I was able to make some of it quite a bit simpler,
 notably the bit about promoting free tyvars.  I'm happy with
 the result.

 Moreover I fixed Trac #13524 at the same time.  Happy days.
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13524#comment:12>
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