[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 crockeea):

 I'm confused here: are you suggesting that you would be able to apply `f`
 to `a`, but not to `b` or `c`, or are you saying you would disallow type
 applications completely on functions that have partial type signatures?

 In the former case, new variables aren't causing my issue; GHC is
 reordering explicitly listed variables. In the latter case, this really
 weakens these two features! I'd rather guess the right order through trial
 and (compile) error than be disallowed completely.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13524#comment:6>
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