intersection returns an extra point in the output

[vissarion]

The following program returns an extra point in 1.84 and develop while that was not the case in 1.77

#include <boost/geometry.hpp>
#include <iostream>

int main() {
    using Point = boost::geometry::model::d2::point_xy<double>;
    using MultiPoint = boost::geometry::model::multi_point<Point>;
    using Polygon = boost::geometry::model::polygon<Point, false>;
    using Linestring = boost::geometry::model::linestring<Point>;
    using MultiPolygon = boost::geometry::model::multi_polygon<Polygon>;
    using MultiLinestring = boost::geometry::model::multi_linestring<Linestring>;

    Polygon p;
    boost::geometry::read_wkt("POLYGON((6 7,18 14,-8 1,0 0,18 -8,6 7),(6 0,-4 3,5 3,6 0))", p);

    MultiPolygon mp;
    boost::geometry::read_wkt("MULTIPOLYGON(((2 3,-3 5,-10 -1,2 3)))", mp);

    std::tuple<MultiPoint, MultiLinestring, MultiPolygon> result;
    boost::geometry::intersection(p, mp, result);

    std::cout << boost::geometry::wkt(std::get<0>(result)) << std::endl;
    std::cout << boost::geometry::wkt(std::get<1>(result)) << std::endl;
    std::cout << boost::geometry::wkt(std::get<2>(result)) << std::endl;

    std::cout << boost::geometry::is_valid(p) << std::endl;
    std::cout << boost::geometry::is_valid(mp) << std::endl;
    std::cout << boost::geometry::is_valid(std::get<2>(result)) << std::endl;
}

In particular:

In 1.84

MULTIPOINT((-7.2 1.4))
MULTILINESTRING()
MULTIPOLYGON(((-5.09091 0.636364,-0.842105 2.05263,-4 3,-7.2 1.4,-7.70909 0.963636,-5.09091 0.636364)),((-1.33333 4.33333,-4 3,2 3,-1.33333 4.33333)))

In 1.77

MULTIPOINT()
MULTILINESTRING()
MULTIPOLYGON(((-5.09091 0.636364,-0.842105 2.05263,-4 3,-7.2 1.4,-7.70909 0.963636,-5.09091 0.636364)),((-1.33333 4.33333,-4 3,2 3,-1.33333 4.33333)))