Throw an error when bindings aren't an obj or func

My attempt at solving issue #1679. Let me know if this has any problems!
I'm sorry Sam, I'm afraid it can't do that. I think you know what the problem is just as well as I do. This function is too important for me to allow you to jeopardize it. I know that you were planning on unwrapping this function, and I'm afraid that it won't catch the error that way.