So, some lenses are designed for crop-sensor bodies, like the EF-S range from Canon, and many other third party lenses.
What happens when you use these on full-frame bodies? I think I heard somewhere that in some cases you can't take the photo because the mirror will strike the back of the lens... in other cases there may be severe vignetting. Is this right? Are there other scenarios? Is there a way to know what scenario I'd get with a particular lens - body combination, without trial and error?
I'm asking because most of my lenses are for crop-sensor bodies, and I'm thinking of going FF. Also, a friend bought a Sigma 10-20mm and is planning to use it on a Nikon D700.