On Wednesday, October 19, 2016 12:48:54 Andrei Alexandrescu via Digitalmars-d wrote: > On 10/19/2016 11:38 AM, Jonathan M Davis via Digitalmars-d wrote: > > On Wednesday, October 19, 2016 07:55:19 Andrei Alexandrescu via > > Digitalmars-d> > > wrote: > >> This was C++'s big un' that led to many complications. If the overload > >> weren't ambiguous, a large part of rvalue references would have been > >> unneeded. (Universal references would still have been necessary for > >> perfect forwarding, but that's not the bulk.) > >> > >> In order to avoid such issues, we steered clear off binding rvalues to > >> ref parameters in the D language. As I mentioned to Ethan, I do agree a > >> careful definition may be able to avoid the fallout that happened in > >> C++. It would be a fair amount of work. > > > > The other big problem is that D's const is so much more restrictive than > > C++'s that even if const ref accepted rvalues, a large portion of the > > time, > > it would be too restrictive to be useful. > > That's why if we allow binding rvalues to references, we'd allow it > regardless of const. -- Andrei
Which then causes the problem that it becomes much less clear whether ref is supposed to be modifying its argument or is just trying to avoid copying it - though good documentation can mitigate that problem. - Jonathan M Davis
