circle_formation_functor call has no effect?

[nkurtov@…]

What effect has the call of circle_formation_functor_.ppp() in boost::polygon::detail::circle_formation_predicate::operator() ? The call seems to have no side effects, because circle_formation_functor_ is stateless and it does not affect voronoi_builder or voronoi_diagram. Is it safe to simply delete the call?

http://www.boost.org/doc/libs/1_64_0/boost/polygon/detail/voronoi_predicates.hpp

class circle_formation_predicate {

bool operator()(const site_type& site1, const site_type& site2,

const site_type& site3, circle_type& circle) {

if (!site1.is_segment()) {

if (!site2.is_segment()) {

if (!site3.is_segment()) {

(point, point, point) sites. if (!circle_existence_predicate_.ppp(site1, site2, site3))

return false;

circle_formation_functor_.ppp(site1, site2, site3, circle); <- This call has no effect, does it?

[anonymous]

'circle' argument is modified by the ppp() call. Please disregard this bug.