[GHC] #4282: Data.List.intersperse not lazy enough

[GHC]

#4282: Data.List.intersperse not lazy enough
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    Reporter:  daniel.is.fischer                   |        Owner:        
        Type:  proposal                            |       Status:  new   
    Priority:  normal                              |    Milestone:        
   Component:  libraries/base                      |      Version:  6.12.3
    Keywords:  intersperse, laziness, intercalate  |     Testcase:        
   Blockedby:                                      |   Difficulty:        
          Os:  Unknown/Multiple                    |     Blocking:        
Architecture:  Unknown/Multiple                    |      Failure:  Other 
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Changes (by daniel.is.fischer):

  * keywords:  intersperse, laziness => intersperse, laziness, intercalate


Comment:

 I've forgotten to explicitly mention that this change would also change
 the behaviour of intercalate from
 {{{
 intercalate sep (xs : _|_) = _|_
 }}}
 to
 {{{
 intercalate sep (xs : _|_) = xs ++ _|_
 }}}
 which I also deem desirable and hence include in the proposal.
 Thanks to Duncan for pointing out the omission.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4282#comment:7>
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