From Ada 2012

[Kagamin]

On Thursday, 3 May 2012 at 14:04:41 UTC, bearophile wrote:
> [p.21]
>> The compiler decides if it has to be passed by reference of 
>> copy
>> 
>> procedure Do_Something
>>  (P1 : in Huge_Structure) –-  Passed by reference if too big
>
> D offers more low-level knowlege/control here, it doesn't 
> decide to pass by value or reference, leaving the decision to 
> the programmer, I prefer D here.
> But in D code like this, where a large value is passed, I'd 
> like the D compiler to give a warning (despite once in a while 
> that's exactly what you want?):
>
> alias int[1_000] TA;
> void int(TA a) {}

I was surprised a little when compiler rejected `ref in`.