__rvalue and Move Semantics first draft - aliasing problem/danger

[Walter Bright]

On 11/10/2024 9:36 AM, Timon Gehr wrote:
> I think the main potential trouble is that there is usually an assumption that 
> there is no aliasing between rvalue arguments.
> 
> For example, if a compiler backend assumes no aliasing, undefined behavior might 
> be introduced if one of the arguments is modified and then the other is read.
> 
> Of course, we can instead specify that the aliasing is legal (but it may still 
> be surprising).

The problem exists anyway.

https://github.com/dlang/DIPs/blob/master/DIPs/accepted/DIP1021.md

This has been incorporated, but is only turned on with a switch.