DIP27 available for destruction

[Timon Gehr]

On 02/27/2013 11:57 AM, deadalnix wrote:
> On Wednesday, 27 February 2013 at 10:38:05 UTC, Timon Gehr wrote:
>>> I considered optional parentheses where you would have an error, but I'm
>>> afraid that this could create weird effect with function overloads.
>>>
>>
>> There are no weird effects with function overloads in what I propose.
>> What is the issue you are seeing?
>>
>
> Consider the following situation :
>
> void foo(uint a) {
>      writeln("a is ", a);
> }
>
> uint bar() {
>      return 0;
> }
>
> foo(bar); // a is 0
>

error: incompatible argument types (uint function()) to function foo(uint a)

> Later, this function is added :
> void foo(uint function() a) {
>      writeln("function not executed");
> }
>
> The statement above become :
> foo(bar); // function not executed
>
> Note that foo can be in other modules, so it may not be obvious. It can
> be solved in various ways, and I actually implemented some to play
> around. I was not satisfied with the result.
>

I see. This problem does not occur. (There is no UFCS in the above code.)

>>> It may be limited to the case where expression can't be used as
>>> statement because it has no effect.
>>
>> Then it is not worth it.
>
> It would kick in with the example you gave.

Not necessarily, it would depend on the context of the expression I gave.