Call site 'ref'

[Jonathan M Davis]

On Monday, January 16, 2012 00:41:14 Timon Gehr wrote:
> Well, struct literals are lvalues, at least in DMD.

Yeah. I don't understand that. I've argued about it with Walter before. 
Apparently they are in C++ as well. I don't understand it. It makes it so that

void func(ref S val)
S bar();

works with

func(S(42));

but not

func(bar());

It seems completely arbitrary to me that it works this way and has IMHO _zero_ 
benefits. And I know that newbies have run into the problem and been completely 
confused by it (e.g. http://stackoverflow.com/questions/6986175/const-ref-and-
rvalue-in-d ). _I_'ve been confused by it. I was stunned to find out that there 
was _any_ difference in the language between a struct literal and an identical 
struct returned from a function.

It's not as big an issue in C++, because using & is fairly rare in C++ unless 
its const, and const & will take temporaries. But in D, it's _definitely_ an 
issue IMHO. I really think that struct literals should be considered rvalues. 
I do _not_ understand why they aren't or why anyone ever thought that it was a 
good idea for them to be lvalues.

- Jonathan M Davis