DIP 1016--ref T accepts r-values--Community Review Round 1

[Petar]

On Friday, 20 July 2018 at 10:08:03 UTC, Dgame wrote:
> On Friday, 20 July 2018 at 09:39:47 UTC, Nicholas Wilson wrote:
>> On Friday, 20 July 2018 at 09:03:18 UTC, Dukc wrote:
>>> appending something (like .byRef or byRef!long, the latter 
>>> making an implicit type conversion)
>>
>> That can't work: either it returns an expired stack temporary 
>> (*very* bad), or allocates with no way to deallocate (bad).
>
> What about something like this?
>
> ----
> import std.stdio;
>
> ref T byRef(T)(T value) {
>     static T _val = void;
>     _val = value;
>
>     return _val;
> }
>
> void foo(ref int a) {
>     writeln("A = ", a);
> }
>
> void main() {
>     foo(42.byRef);
>     foo(23.byRef);
> }
> ----

Perhaps semantically correct, but practically a non-starter, due 
to the performance implications of loading and storing to 
thread-local storage and by extension the severe impact on 
compiler optimizations. And also syntactically ugly, even if you 
shorten it to something like `1.r`.

Anyway, I think the DIP is the best way forward - just remove the 
stupid and unnecessary restriction.