How to access private variable of outer class from an inner struct

[matheus]

On Sunday, 15 January 2023 at 12:44:51 UTC, thebluepandabear 
wrote:
> ...
> How will the variable `outer` become the reference to the 
> current `X` object (if that makes sense?). Does the compiler do 
> it automatically?

I think you'll need to do this:

class X {
     private int num;

     struct Y {
         X outer;
         int fun() { return outer.num; }
     }

     Y y;
     this(){
         y = Y(this);
     }
}

void main(){
     import std.stdio : writeln;
     auto x = new X();
     x.num = 10;
     writeln(x.num);
     writeln(x.y.fun());
}

Prints:

10
10

Matheus.