Can we just have struct inheritence already?

[Manu]

On Thu, Jun 13, 2019 at 7:35 AM Exil via Digitalmars-d
<digitalmars-d at puremagic.com> wrote:
>
> On Thursday, 13 June 2019 at 06:43:44 UTC, Manu wrote:
> > This should obviously be a compile error:
> >   struct A { int x; }
> >   struct B : A { int y; }
> >   B b;
> >   A a = b; // <- obviously an error
>
>
> It doesn't become so obvious when you can implicitly convert to
> the base type.
>
>      A foo(ref A a) { return a; }
>
>      B b;
>      A a = foo(b);

So don't implicitly convert to the base type?
B extends A, but I don't think it's a kind of A as for polymorphic classes.