Extended static checking (ESC) is a collective name in computer science for a range of techniques for statically checking the correctness of various program constraints. ESC can be thought of as an extended form of type checking. As with type checking, ESC is performed automatically at compile time (i.e. without human intervention). This distinguishes it from more general approaches to the formal verification of software, which typically rely on human-generated proofs. Furthermore, it promotes practicality over soundness, in that it aims to dramatically reduce the number of false positives (overestimated errors that are not real errors, that is, ESC over strictness) at the cost of introducing some false negatives (real ESC underestimation error, but that need no programmer's attention, or