Call site 'ref'

[Timon Gehr]

On 01/15/2012 11:41 PM, Peter Alexander wrote:
> On 15/01/12 10:10 PM, Timon Gehr wrote:
>> Another thing that would have to be discussed: what happens to const ref
>> parameters? It is very reasonable that someone will decide to change
>> calling conventions from by value to by const ref or the other way round
>> after profiling. It is very convenient that such a change is
>> syntactically transparent to the caller and this should stay.
>
> Actually, that would be very dangerous. const ref does not have the
> privilege of being able to bind to rvalues in D like it does in C++.
>
> void foo(const ref int x) {...}
>
> foo(1); // this is legal in C++, but illegal in D
>

Who on earth wants to change an int parameter from by value to by const 
ref? struct literals can bind to const ref parameters so there is 
absolutely no issue.

> In case, const ref would not require the ref at call site because
> there's no danger of it being modified.
>

The semantics are still not the same.