structs are now lvalues - what is with "auto ref"?

[Namespace]

> Plenty of people are using it with the problems that it 
> currently has

But how long?

For the moment (or the next 2, 3 releases) it should be enough if 
I write
void foo()(auto ref const Foo f) {
instead of
void foo(ref const Foo f) {

or is there any difficulty? After all it's a template now.