Preview switches

[Stanislav Blinov]

On Saturday, 20 June 2020 at 14:36:25 UTC, Q. Schroll wrote:

> While "implement <DIP link omitted>" do link to documents 
> explaining details, I have no idea what `rvaluerefparam` does 
> exactly. Is there an (online) resource where details to the 
> others are given or linked?

Ostensibly, it should enable binding of rvalues (temporaries) as 
ref arguments for functions (a-la how in C++ temporaries bind to 
const T&), i.e.

Tea makeSomeTea() { /* ... */ }

void takeSomeTea(ref const Tea) { /* ... */ }

void main()
{
     takeSomeTea(makeSomeTea());
}

Without that switch, the above won't compile, because 
historically D disallowed such binding. Manu (among others) 
pushed for this to be possible, hence the switch. Though 
implementation, AFAICT, is still somewhere in the "under 
construction" territory, judging by Bugzilla.