References in D

[Maxim Fomin]

On Saturday, 15 September 2012 at 14:17:53 UTC, Simen Kjaeraas 
wrote:
>> And in real code it could crash after dereferencing and before 
>> passing to bar, if accessed (meaning that problem is in 
>> erroneous pointer usage, not accepting ints through reference 
>> in bar). Certainly, it is possible to break even in such 
>> cases, as well as in other parts of the language which doesn't 
>> necessarily mean that such parts of the language are broken. 
>> What I was talking about is:
>>
>> void bar( ref int n ) {
>>     n = 3;
>> }
>>
>> void main( ) {
>>     int* p = null;
>>     bar(p); // error
>>     bar(null); //error
>> }
>
> But that's like saying bar(int n) doesn't accept null as a 
> parameter - of
> course it doesn't - int and int* are different types.
>
> What I'm saying is references may be a bit safer than pointers, 
> but the
> 'guarantee' that they're not null pointers in disguise is a lie.

Again, what is the talk about? References in function parameters 
or class objects? In the first case ref parameter has nothing to 
do with whether was a valid object passed to function or not (as 
like in your case). It only means that function works with actual 
object, not a copy. Obviously, it is impossible to pass a pointer 
or null when other type is expected.

If you speaking about class objects, than certainly it may 
reference a valid region of memory or null (in bad and rare 
cases, to random memory).