Greer, Joe wrote:
[Joe] Tossing in my own $.02, this Joe tends to agree somewhat with the other Joe. :) If I wanted to swap p and q, I can do that today without the move.
Not in a generic way, though. Move is about performance. For some types, swap is slower than copy. There is also the use case of a = f(); where you automatically get the move assignment if f() returns an rvalue, and an ordinary copy otherwise.
On the other hand, if I move a value from q to p, I expect p's contents to be gone, not to be transferred to q.
In 99.4% of the use cases for move, q is a temporary and you don't care what it holds, since it will be destroyed anyway at the end of the expression. Decreasing the performance for the majority to appease a minority which would like to move from lvalues and have them in a predictable state afterwards seems like a questionable tradeoff to me. Not necessarily wrong, just questionable. :-)