function default arguments depending on other arguments

[Tove via Digitalmars-d]

On Friday, 18 July 2014 at 17:40:23 UTC, Timon Gehr wrote:
> On 07/18/2014 12:00 AM, Trass3r wrote:
>> void foo(int a, int b = a)
>> {
>> }
>> is illegal in C++ because order of evaluation is undefined.
>>
>> But since D defines the order to be left to right couldn't it 
>> also allow
>> this?
>
> It could, and I think it is an unnecessary limitation that it 
> currently does not. (This can also be useful if that parameter 
> is the hidden 'this' reference.)

This request keeps popping up, I've seen it at least 3 times 
before and there's even an enhancement request for it:
https://issues.dlang.org/show_bug.cgi?id=8075

IIRC:
Walter's stance was that he needs compelling examples, which 
proves the utility of this new feature.