struct A
{
int blah;
}
class B
{
    A* a;
    this(A* _a)
    {
        writeln(_a)
        a =_a;
    }
}

class C : B
{
    this(A* _a)
    {
        writeln(_a)
        super(_a);
    }
}
int main(string[] args)
{
        A a;
        writeln(&a);
        C c = new C(&a);
}

prints
7FFF56E787F8
7FFF56E787F8
null

??? What is happening here?

On Tuesday, 23 February 2016 at 09:16:08 UTC, Nicholas Wilson wrote:
> struct A
> {
> int blah;
> }
> class B
> {
>     A* a;
>     this(A* _a)
>     {
>         writeln(_a)
>         a =_a;
>     }
> }
>
> class C : B
> {
>     this(A* _a)
>     {
>         writeln(_a)
>         super(_a);
>     }
> }
> int main(string[] args)
> {
>         A a;
>         writeln(&a);
>         C c = new C(&a);
> }
>
> prints
> 7FFF56E787F8
> 7FFF56E787F8
> null
>
> ??? What is happening here?

fwiw I can reassign the reference (in the classes) to a after B's call to super but still ...

On Tuesday, 23 February 2016 at 09:16:08 UTC, Nicholas Wilson wrote:
> struct A
> {
> int blah;
> }
> class B
> {
>     A* a;
>     this(A* _a)
>     {
>         writeln(_a)
>         a =_a;
>     }
> }
>
> class C : B
> {
>     this(A* _a)
>     {
>         writeln(_a)
>         super(_a);
>     }
> }
> int main(string[] args)
> {
>         A a;
>         writeln(&a);
>         C c = new C(&a);
> }
>
> prints
> 7FFF56E787F8
> 7FFF56E787F8
> null
>
> ??? What is happening here?

I can't reproduce this. After making a few changes to get the code to compile (adding ; after the first two writeln's, and changing int main to void main), everything works as expected. Which compiler and version are you using?

On Tuesday, 23 February 2016 at 10:47:17 UTC, Rene Zwanenburg wrote:
> On Tuesday, 23 February 2016 at 09:16:08 UTC, Nicholas Wilson wrote:
>> struct A
>> {
>> int blah;
>> }
>> class B
>> {
>>     A* a;
>>     this(A* _a)
>>     {
>>         writeln(_a)
>>         a =_a;
>>     }
>> }
>>
>> class C : B
>> {
>>     this(A* _a)
>>     {
>>         writeln(_a)
>>         super(_a);
>>     }
>> }
>> int main(string[] args)
>> {
>>         A a;
>>         writeln(&a);
>>         C c = new C(&a);
>> }
>>
>> prints
>> 7FFF56E787F8
>> 7FFF56E787F8
>> null
>>
>> ??? What is happening here?
>
> I can't reproduce this. After making a few changes to get the code to compile (adding ; after the first two writeln's, and changing int main to void main), everything works as expected. Which compiler and version are you using?

v2.067-devel-e431363
 I "fixed" it see above.

On 2/23/16 6:05 AM, Nicholas Wilson wrote:
> On Tuesday, 23 February 2016 at 10:47:17 UTC, Rene Zwanenburg wrote:
>> On Tuesday, 23 February 2016 at 09:16:08 UTC, Nicholas Wilson wrote:
>>> struct A
>>> {
>>> int blah;
>>> }
>>> class B
>>> {
>>>     A* a;
>>>     this(A* _a)
>>>     {
>>>         writeln(_a)
>>>         a =_a;
>>>     }
>>> }
>>>
>>> class C : B
>>> {
>>>     this(A* _a)
>>>     {
>>>         writeln(_a)
>>>         super(_a);
>>>     }
>>> }
>>> int main(string[] args)
>>> {
>>>         A a;
>>>         writeln(&a);
>>>         C c = new C(&a);
>>> }
>>>
>>> prints
>>> 7FFF56E787F8
>>> 7FFF56E787F8
>>> null
>>>
>>> ??? What is happening here?
>>
>> I can't reproduce this. After making a few changes to get the code to
>> compile (adding ; after the first two writeln's, and changing int main
>> to void main), everything works as expected. Which compiler and
>> version are you using?
>
> v2.067-devel-e431363
>   I "fixed" it see above.
>

This is not a released version. Using both 2.067.1 and 2.068.0, I get the expected behavior. There could have been a regression fixed between that version and the release, I suggest you try a released version: http://dlang.org/download.html#dmd

-Steve