Discussion Thread: DIP 1040--Copying, Moving, and Forwarding--Community Review Round 1

[Walter Bright]

On 3/10/2021 8:17 PM, tsbockman wrote:
> On Thursday, 11 March 2021 at 03:33:31 UTC, Walter Bright wrote:
>> On 3/10/2021 5:27 PM, tsbockman wrote:
>>> Yeah, studying the DIP I can't figure out what problem the move `opAssign` is 
>>> supposed to solve that the constructor doesn't:
>>> https://forum.dlang.org/post/kzgybicwqwlfyiiefucc@forum.dlang.org
>>
>> The thing about "destroy after move" is to deal with the case of both the 
>> source and the destination referring to the same object. The concern is that 
>> destroying the destination's original contents first will destroy them for the 
>> source before it gets moved in.
> 
> Wouldn't it make more sense to just skip the move operation entirely when the 
> source and destination are the same? Or are there circumstances in which that 
> cannot be determined, even at runtime?

The idea is that the move assignment operation takes care of this, and makes it 
"as if" the move was done, then the destruction.