From Ada 2012

[Steven Schveighoffer]

On Thu, 03 May 2012 13:03:34 -0400, Kagamin <spam at here.lot> wrote:

> 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`.

in is synonymous for "const scope".

Doing "const scope ref" yields:

"scope cannot be ref or out"

which makes sense.  Just use const instead.

-Steve