.Tail objects no longer wrongly deleted with `copy-object` Previously, there was a reference count invariant on tail objects that was not maintained when an object was copied to itself. This caused the existing object was changed, rather than copied. As a result, references to tail objects were being decremented. When the refcount on tail objects dropped to 0, they were deleted during the next garbage collection (GC) cycle. With this fix, the refcount on tail objects is no longer decremented when completing a copy-to-self.