I was just sitting in my non photography class today and the idea popped into my head. I know with flash bounce you're supposed to use a white wall to diffuse the light.

But what happens if the ceiling or all behind/side of you is a mirror? Will it make the light even harsher or appear more directional like light from a window?

I'm going to a wedding soon (not as the actual photographer) and I was just wondering what would happen in that scenario.