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In stead of using a complex compound aspect we can now introduce members and specify an action if the member is already there. The PropertyChanged event member will be added to the class if it is not already on the class. Nice code 
Unfortunately PostSharp 2 is far from ready and even the samples don't work completely 
Another downside is that is not backwards compatible with 1.5 so existing aspects need to reviewed.
I added a test solution to https://repos.deltares.nl/repos/delft-tools/trunk/sandbox/PostSharp2
to play around with the new post sharp.