[GHC] #3966: Warn about useless UNPACK pragmas

[GHC]

#3966: Warn about useless UNPACK pragmas
---------------------------------------------+------------------------------
  Reporter:  tibbe                           |          Owner:                  
      Type:  feature request                 |         Status:  new             
  Priority:  normal                          |      Milestone:  7.4.3           
 Component:  Compiler                        |        Version:  6.12.1          
Resolution:                                  |       Keywords:                  
        Os:  Unknown/Multiple                |   Architecture:  Unknown/Multiple
   Failure:  None/Unknown                    |     Difficulty:  Unknown         
  Testcase:  typecheck/should_compile/T3966  |      Blockedby:                  
  Blocking:                                  |        Related:                  
---------------------------------------------+------------------------------

Comment(by tibbe):

 Replying to [comment:4 simonmar]:
 > Replying to [comment:3 tibbe]:
 > > This warning seems to have disappeared again in 7.4.1.
 >
 > The test is passing... can you supply some repro code please?
 >

 {{{
 module Repro where

 data T a = C {-# UNPACK #-} !a
 }}}

 Compiles fine without a warning.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/3966#comment:5>
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