title: Block access to System classes in class library
body: <p>Can anyone recommend a way to block access to particular system classes in a particular assembly?  For example I may want to block FileStream or other I/O classes in a class library that implements a certain layer that shouldn't involve I/O.  It doesn't have to be insurmountable, the point isn't to combat hostile developers, only to reduce layering errors by team members (including myself) and easily identify such code by breaking the compile.</p>