In my version of Unity, I was getting the following errors:
Assets\Scripts\Dropper.cs(10,18): warning CS0108: ‘Dropper.renderer’ hides inherited member ‘Component.renderer’. Use the new keyword if hiding was intended.
I had to change the variable names for “renderer” and “rigidbody” to “ojbectRenderer” and “objectRigidbody” to remove this conflict.