Rvalue references - The resolution

[Steven Schveighoffer]

On Mon, 06 May 2013 06:43:38 -0700, Andrei Alexandrescu  
<SeeWebsiteForEmail at erdani.org> wrote:

> I think we can technically make the overloading work while also allowing  
> binding rvalues to ref. But that wouldn't help any. Consider:
>
> ref int min(ref int a, ref int b) { return b < a ? b : a; }
> ...
> int x;
> fun(min(x, 100));
>
> Here the result of min may be bound to an lvalue or an rvalue depending  
> on a condition. In the latter case, combined with D's propensity to  
> destroy temporaries too early (immediately after function calls), the  
> behavior is silently undefined; the code may pass unittests.

Wouldn't the new runtime check fix this?

> This is a known issue in C++. Allowing loose binding of rvalues to ref  
> not only inherits C++'s mistake, but also adds a fresh one.

I thought C++ would handle this kind of code.  I remember being able to  
use references to rvalues in ways that were unintuitive, but not undefined.

-Steve