Move constructors fix a narrow problem, which is, when you have something like a vector append, how do you copy over all the previous elements as a "shallow" copy rather than a deep one?
In C with realloc(), it's just assumed that memcpy works for that. With C++03 and earlier copying the elements could very well end up duplicating everything on the heap for no reason, then discarding the old copy.
How does rust do this? What I am reading from googling is that every assignment is a move?
