[Bug or feature] nested class inheritance

[David Ferenczi]

>> Compiling the code below gives an error message:
>>
>> ----------------8<---------------------------------
>> int main(char[][] args)
>> {
>>     class A
>>     {
>>         protected:
>>             class AA {}
>>     }
>>
>>     class B : A
>>     {
>>         protected:
>>             class BB : AA {}
>>     }
>>
>>     return 0;
>> }
>> ----------------8<---------------------------------
>>
>>
>> test.d(15): class test.main.B.BB super class AA is nested within A, not B
>>
>>
>> Is it the intended behaviour?
> Yes
> 
>> Does it mean that nested classes wont get inherited, thus cannot be used
>> in the subclass?
> 
> No. The classes are defined inside a function and thus:
> # (http://www.digitalmars.com/d/function.html)
> # Unlike module level declarations, declarations within function scope
> # are processed in order.
> #
> 
> Thomas

Thank you very much for the quick answer.
Maybe I miss some important point, but I don't understand why the processing
order explains the behaviour.

In my original code the situation looks like this:

a.d:
----------------8<---------------------------------
class A
{
    protected:
        class AA {}
}
----------------8<---------------------------------

b.d:
----------------8<---------------------------------

static private import a: A;

class B : A
{
    protected:
        class BB : AA {}
}
----------------8<---------------------------------

What I would like to do is to nest AA class in A. Let another class B in
another module inherit from A. Let B have a nested class BB, which inherits
from AA.

What should I do to achieve this? Or is it totally worng?

If I put class AA outside A, everything works.

a.d:
----------------8<---------------------------------
class A
{
        
}

class AA
{

}
----------------8<---------------------------------

b.d:
----------------8<---------------------------------

static private import a: A, AA;

class B : A
{
    protected:
        class BB : AA {}
}
----------------8<---------------------------------

Thank you very much for your help,

David