[GHC] #9725: Constraint deduction failure

[GHC]

#9725: Constraint deduction failure
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              Reporter:  heisenbug   |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
  (Type checker)                     |         Keywords:
            Resolution:              |     Architecture:  Unknown/Multiple
      Operating System:              |       Difficulty:  Unknown
  Unknown/Multiple                   |       Blocked By:
       Type of failure:  GHC         |  Related Tickets:
  rejects valid program              |
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by goldfire):

 ETA on my work is "not 7.10". There are three primary things that my work
 (for now) addresses: 1) kind equalities in terms, 2) promoted GADTs, and
 3) promoted type families. Item (1) feels quite close to start the
 discussion about merging, maybe a few more weeks. (2) and (3) are in the
 2-3 month timeframe, I think. However, I think it's reasonable to consider
 merging (1) even if (2) and (3) are unfinished. (1) by itself will solve
 this problem, and the `dynApply` problem highlighted in wiki:Typeable.

 In any case, my campaign toward merging won't start in earnest until I
 have something to show that I'm proud of, and that time isn't quite yet.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9725#comment:12>
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