[GHC] #11735: Optimize coercionKind

[GHC]

#11735: Optimize coercionKind
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        Reporter:  goldfire          |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by goldfire):

 I'm sorry -- I don't understand the first part of comment:37. Getting a
 kind should never require getting a role. That's why there is a version of
 `coercionKind` that's a standalone function. Let's assume you got these
 two swapped. Even then, I'm not sure what you're describing; it seems
 you're describing your 'un-refactored" version keeping roles and kinds
 separate. If they are together (as in HEAD), I don't see the quadratic
 behavior.

 And yet, something goes terribly wrong in HEAD, even without this
 quadratic behavior. But what?? Or maybe I'm completely missing something
 here.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11735#comment:38>
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