As Andreas points out this is because this apparent method call is
actually compiled by the compiler.  (And the error is actually from the
compiler, not a result of sending the message.)  Perhaps incorrectly
depending on your point of view.  I would recommend using 'ifNotNilDo:'
instead when you want the offending object.

Ken

On Sat, 2006-09-02 at 00:25 +0100, Zulq Alam wrote:
> Hi List,
> 
> Why does "Object new ifNotNil: [:object | ]" result in the syntax error 
> "argument of ifNotNil: must be a 0-argument block" when the code appears 
> to be fine with this?
> 
> 
> ProtoObject>>ifNotNil: ifNotNilBlock
> 	"Evaluate the block, unless I'm == nil (q.v.)"
> 
> 	^ ifNotNilBlock valueWithPossibleArgs: {self}
> 
> 
> BlockClosure>>valueWithPossibleArgs: anArray
> 
> 	| n |
> 	(n := self numArgs) = 0 ifTrue: [^ self value].
> 	n = anArray size ifTrue: [^ self valueWithArguments: anArray].
> 	^ self valueWithArguments: (n > anArray size
> 		ifTrue: [anArray, (Array new: n - anArray size)]
> 		ifFalse: [anArray copyFrom: 1 to: n]): anArray
> 
> 
> 
> A quick search of Mantis for ifNotNil or valueWithPossibleArgs hasn't 
> left me any wiser. Something to do with the interpreter, perhaps 
> optimisation?
> 
> Thanks,
> Zulq.
> 
> 
> 
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