Currently, we are not dealing with tf.function decorator parameter values, just with the existence of those parameters.

Do we need dataflow or does parsing literals enough? How often are variables used to decorator arguments? Can we tell when variables are used? If we go only with literals, can we throw an exception when a variable is used so that we know how many times this happens. Better yet, we can "fail" the function by adding a precondition failure to the function. In other words, if we can't exact the decorator argument, chances are we won't be able to get a good handle on the function's status.