[GHC] #3221: Incorrect "defined but not used" warning for data types using deriving

[GHC]

#3221: Incorrect "defined but not used" warning for data types using deriving
--------------------------------------------+-------------------------------
    Reporter:  NeilMitchell                 |        Owner:                  
        Type:  bug                          |       Status:  closed          
    Priority:  normal                       |    Milestone:  6.12 branch     
   Component:  Compiler                     |      Version:  6.10.2          
    Severity:  normal                       |   Resolution:  fixed           
    Keywords:                               |   Difficulty:  Unknown         
    Testcase:  rename/should_compile/T3221  |           Os:  Unknown/Multiple
Architecture:  Unknown/Multiple             |  
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Changes (by simonpj):

  * testcase:  => rename/should_compile/T3221
  * status:  new => closed
  * resolution:  => fixed

Comment:

 Fixed by
 {{{
 Wed May 27 19:21:57 BST 2009  simonpj at microsoft.com
   * Fix Trac #3221: renamer warnings for deriving clauses

   This patch arranges to gather the variables used by 'deriving' clauses,
   so that unused bindings are correctly reported.
 }}}

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3221#comment:2>
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