state_vars_test5.m:020: In clause for `p(out)':
state_vars_test5.m:020:   mode error: argument 1 did not get sufficiently
state_vars_test5.m:020:   instantiated.
state_vars_test5.m:020:   Final instantiatedness of `STATE_VARIABLE_X' was
state_vars_test5.m:020:   `free',
state_vars_test5.m:020:   expected final instantiatedness was `ground'.
state_vars_test5.m:020: In clause for predicate `p'/1:
state_vars_test5.m:020:   warning: variable `STATE_VARIABLE_X' occurs only once
state_vars_test5.m:020:   in this scope.