Some aspects of the present disclosure provide for a system and method to discover which parts of a design a formal test suite can detect faults in, and thus how much of a design structure is covered by a property set. A mutatable RTL design is defined which allows for modification of a part of an RTL design from its intended behavior to a non-intended behavior, thus introducing unwanted effects. The mutatable RTL design can then be synthesized to produce a functional representation of the design. The property set can be re-run on the synthesized design to see whether the functional representation of the design is sensitive to the unwanted effect and thus whether formal verification can detect the modification.