[GHC] #2822: Arity expansion not working right

[GHC]

#2822: Arity expansion not working right
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    Reporter:  simonpj                   |        Owner:                  
        Type:  run-time performance bug  |       Status:  new             
    Priority:  normal                    |    Milestone:  6.10 branch     
   Component:  Compiler                  |      Version:  6.10.1          
    Severity:  normal                    |   Resolution:                  
    Keywords:                            |   Difficulty:  Unknown         
    Testcase:                            |           Os:  Unknown/Multiple
Architecture:  Unknown/Multiple          |  
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Comment (by batterseapower):

 This is happening because at the time we compile GHC.Handle, the Prelude
 module has not yet been compiled. This means that Prelude.catch is
 pesimistically assumed to have an arity of 0, so openFile can only have an
 arity as large as the number of leading lambdas it has - i.e. 2.

 I don't think there is a clean solution for this without whole-program
 compilation.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/2822#comment:2>
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