[GHC] #9356: scanl does not participate in list fusion

[GHC]

#9356: scanl does not participate in list fusion
-------------------------------------+-------------------------------------
              Reporter:  dfeuer      |            Owner:
                  Type:  bug         |           Status:  infoneeded
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:  Runtime     |       Blocked By:
  performance bug                    |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
-------------------------------------+-------------------------------------
Changes (by nomeata):

 * status:  patch => infoneeded


Comment:

 Can you extend the patch with a bit more comments? In particular, why do
 you need this `tailScanl`, when with other functions, the `fooList` rule
 writes it back to the direct code?

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9356#comment:6>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler