[GHC] #1835: Provide information of the instance environment

[GHC]

#1835: Provide information of the instance environment
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  Reporter:  guest             |          Owner:  igloo           
      Type:  feature request   |         Status:  patch           
  Priority:  normal            |      Milestone:  _|_             
 Component:  Template Haskell  |        Version:  6.8.1           
Resolution:                    |       Keywords:                  
  Testcase:                    |      Blockedby:                  
Difficulty:  Unknown           |             Os:  Unknown/Multiple
  Blocking:                    |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown      |  
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Comment(by SamAnklesaria):

 As far as the first issue goes, `isClassInstance` needs to be separate
 from the information returned by ClassI because of the situations you
 outlined before: type synonyms don't show up, and to search through
 parameterized instances would require unification. So it's easier just to
 use the built in class lookup functionality, and make ClassI and
 isClassInstance have nothing to do with each other, as I've done.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/1835#comment:19>
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