How does energy (from fusion reactions still inside the sun) still have gravitational attraction? In this answer they say:


  While the conversion of mass matter† to energy in the Sun's core now represents a loss of mass proper matter, it turns out that that energy (trapped in the Sun and slowly diffusing towards the surface) will have the same gravitational attraction as the matter it came from until it actually escapes the Sun!


Now I expect that when mass is converted to energy, it has become an electromagnetic wave that can propagate through matter or empty space. 

My question is: How does energy (from fusion reactions still inside the sun) still have gravitational attraction?
I think it is best not to think of energy having a gravitational attraction, rather that energy, like mass, (since they are equivalent keeping in mind c) will curve spacetime.  Electric charges, magnets, and electromagnetic fields will curve spacetime, Scientific American. So whether it is mass or energy, they both will affect the curvature of spacetime, and the sun's total impact on spacetime will not change.