The liabilities of binding rvalues to ref

[Jonathan M Davis]

On Thursday, May 09, 2013 21:56:53 Steven Schveighoffer wrote:
> What about specifying ref at the call site when you know you want the data
> modified?
> 
> fix(ref c[i]);
> 
> Then if c decides to start returning by value, this is a compiler error.
> 
> IMO, fix really should take a pointer. But we want to avoid pointers due
> to the danger of them.
> 
> so this is like applying & but keeps it safe.

That would be great except for UFCS. How would you designate the ref when it's 
the first argument? And I think that it's worse to have ref optional at the 
callsite than to not have it at all.

If it weren't for UFCS, I probably would be in favor of requiring it at the 
callsite, but I just don't see how that could work with UFCS. Maybe C# has a 
way to deal with that, since it does have some sort of UFCS, and it does 
require ref at the callsite (at least from what I understand - I haven't used 
C# much)?

- Jonathan M Davis