[GHC] #9151: Recursive default associated types don't kind-generalize properly

[GHC]

#9151: Recursive default associated types don't kind-generalize properly
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              Reporter:  goldfire    |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.2
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by simonpj):

 I'm reluctant to change the way that associated type defaults are kind-
 checked; but solving #9200 will also allow this program to be kind-
 checked.  `ToEnum` will be treated as having a CUSK, and hence will
 support polymorphic recursion.

 Simon

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9151#comment:13>
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