[GHC] #6026: Unboxed operators have wrong fixity

[GHC]

#6026: Unboxed operators have wrong fixity
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    Reporter:  benl              |       Owner:                             
        Type:  bug               |      Status:  new                        
    Priority:  normal            |   Milestone:                             
   Component:  libraries/base    |     Version:  7.4.1                      
    Keywords:                    |          Os:  Unknown/Multiple           
Architecture:  Unknown/Multiple  |     Failure:  Incorrect result at runtime
  Difficulty:  Unknown           |    Testcase:                             
   Blockedby:                    |    Blocking:                             
     Related:                    |  
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Changes (by simonpj):

  * difficulty:  => Unknown


Comment:

 Good point.  Here's the deal.

  * `LoadIface.ghcPrimIface` gives the `Iface` data structure for
 `GHC.Prim`, which includes all primops.

  * You'll see that it give a fixity for `seq`, but not for any of the
 `PrimOp`s. This is plainly wrong, as this ticket points out.

  * The wrong way to fix it is to add a long list of fixities to
 `ghcPrimIface`.  Wrong because there are a lot of infix primops, and the
 list will change.

  * The right way to fix it is to allow `prelude/primops.txt.pp` to specify
 the fixity of a primop.  There is a pattern to follow: the `strictness` or
 `out_of_line` fields.  Then the program that processes `primops.txt.pp`
 can generate a function `primOpFixity :: PrimOp -> Fixity`, and
 `ghcPrimIface` can use that function to populate the fixity information.

 Not clear how important this is... it's been this way for a long time.
 But yes, a useful task.

 Simon

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6026#comment:2>
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