When you are using Objects as methods, MethodWrappers, or whatever with run:with:in, you have to implement not only that method, but also flushCache doing nothing because it is used in: MethodDictionary >> at: put: at: key put: value "Set the value at key to be value." | index | index := self findElementOrNil: key. (self basicAt: index) == nil ifTrue: [tally := tally + 1. self basicAt: index put: key] ifFalse: [(array at: index) flushCache]. array at: index put: value. self fullCheck. ^ value Ok, I can implement that in my classes, and in MethodWrappers, but I think it would be nicer and cleanly if you only have to implement run:with:in: since flushChache doesn't make sense for normal objects. So, I would like to change that code to at: key put: value "Set the value at key to be value." | index | index := self findElementOrNil: key. (self basicAt: index) == nil ifTrue: [tally := tally + 1. self basicAt: index put: key] ifFalse: [(array at: index) isCompiledMethod ifTrue: [flushCache]]. array at: index put: value. self fullCheck. ^ value Yes, yes, I know the if is ugly, but it gives us a cleaner way to define objects as methods. The other option is to implement flushCache in Object doing nothing but I like it less than this. opinions? thanks mariano