[GHC] #7162: RULES that never fire (automatically)

[GHC]

#7162: RULES that never fire (automatically)
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  Reporter:  andygill          |          Owner:                  
      Type:  feature request   |         Status:  new             
  Priority:  normal            |      Milestone:  7.8.1           
 Component:  Compiler          |        Version:  7.7             
Resolution:                    |       Keywords:                  
        Os:  Unknown/Multiple  |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown      |     Difficulty:  Unknown         
  Testcase:                    |      Blockedby:                  
  Blocking:                    |        Related:                  
-------------------------------+--------------------------------------------

Comment(by simonpj):

 Yes (1) looks best to me.  Alternatively, you could make `[~]` parse as an
 activation but check in INLINE and SPECIALISE productions that it didn't
 come back as `NeverActive`.

 Regardless, please add comments in the parser to explain what is going on.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7162#comment:11>
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