[GHC] #7224: Polymorphic kind annotations on type classes don't always work as expected

[GHC]

#7224: Polymorphic kind annotations on type classes don't always work as expected
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    Reporter:  slindley                 |       Owner:                           
        Type:  bug                      |      Status:  merge                    
    Priority:  normal                   |   Milestone:                           
   Component:  Compiler (Type checker)  |     Version:  7.6.1-rc1                
    Keywords:  kind polymorphism        |          Os:  Unknown/Multiple         
Architecture:  Unknown/Multiple         |     Failure:  GHC rejects valid program
  Difficulty:  Unknown                  |    Testcase:  polykinds/T7224          
   Blockedby:                           |    Blocking:                           
     Related:                           |  
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Changes (by simonpj):

  * status:  new => merge
  * difficulty:  => Unknown
  * testcase:  => polykinds/T7224


Comment:

 Thanks for the report.  The declaration of {{{PMonad'}}} is bogus becuase
 you are using a ''kind'' variable `i` in a ''type'', the type of
 {{{ret'}}}.  Now GHC says
 {{{
 T7224.hs:10:19:
     Kind variable `i' used as a type
     In the type `a -> m i i a'
     In the class declaration for PMonad'
 }}}
 Merge to 7.6 branh.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7224#comment:3>
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