i had the idea it would be very nice to have light reflection
right now if you have a reflecting sphere or cube, it very nicely reflects the surroundings
but wouldnt it be more realistic if for example lights get reflected as well. that you can for example illuminate around a corner without having to use a separate light
if it is not possible. thats okay with me but i just had this idea on how to make the engine better.
ill include some pictures to demonstrate what i mean

in this image you see that the light hits the object but nothing happens
it just relfects the scenery

and in this one you can see that the light around the corner also illuminates the corridor around the corner
you will see both the scenery and the illumination of the light.

You can fake this by using multiple Line Traces. You check if the Light hits the Mirror. If so, activate a second Light at the Mirror.
What you want is Global Illumination. I’m not sure if it can handle Light reflections, but have you tried Light Propagation Volume? It’s a GI Solution.

This is what Global Illumination is doing.
The main supported GI solution in UE4 is Lightmass, it’s static though(You “bake” lighting for levels and can’t modify GI during runtime/gameplay)

As @Raildex_ mentioned, there is also dynamic LPV, but it’s not ready for production and I doubt it will get any updates anytime soon