[with T = int]’:
./Machinarium/Classes/Geometry/Vector2.cpp:102:16: required from here
./Machinarium/Classes/Geometry/Vector2.cpp:27:36: error: passing ‘const Vector2D<int>’ as ‘this’ argument discards qualifiers [-fpermissive]
27 | return DVector(2)<T>(this->x() + vector2d.x(), this->y() + vector2d.y());
./Machinarium/Classes/Geometry/Vector2.h:8:23: error: invalid covariant return type for ‘Vector2D<T> Vector2D<T>::add_by_number(T) [with T = int]’
8 | #define DVector(name) Vector ## name ## D
./Machinarium/Classes/Geometry/Vector2.cpp:36:36: note: in expansion of macro ‘DVector’
36 | template<typename T> DVector(2)<T> DVector(2)<T>::add_by_number(T value)
| ^~~~~~~