I'm trying to write a rule to check a certain object type is always used as part of a 'using' code block. I get the impression that the only way to do this is by doing some source walking - I find no 'VisitUsing' method. Looking at my source in ILDASM, it appears that using blocks are compiled to try --> finally blocks, with object initialisation before the try. I assume, therefore, that there is no explicit way to identify this in FxCop?