A check that INSPECT makes in which all occurrences of a symbol
    are checked for consistency. For example, you can ensure that
    all calls to a routine have the correct number and type of
    arguments. In this type of check, each occurrence is compared
    with a single occurrence selected by INSPECT to be the standard
    against which all occurrences are checked. In this type of check,
    each particular occurrence is either correct or incorrect.