If you use it for producing the Box in the return value, you have to move out of it, and then it's gone. If you don't move it, you have a use-after-free bug aft

If you use it for producing the Box in the return value, you have to move out of it, and then it's gone. If you don't move it, you have a use-after-free bug after the first such panic has been caught and the box has been dropped as a result.