Can we just have struct inheritence already?

[Olivier FAURE]

On Tuesday, 18 June 2019 at 12:17:36 UTC, Manu wrote:
> As base structs specifically. I really want struct inheritance, 
> and
> zero sized fields does happen to be one thing that falls out of 
> that.
> There are 2 things I hate about it; one is the crappy static-if 
> hack
> required to deal with zero-sized bases, the other is that I 
> have to
> use `alias this` to describe a base.
> alias this *should* be a very niche feature, but instead we 
> abuse it
> in lieu of struct inheritance, and no way to perform implicit
> conversion. In both cases it's a gross code smell, and I hate 
> it.

It might be because I write a lot less generic code than you do, 
but I really don't understand why you lend so much importance to 
implicit conversion.

XavierAP's question is particularly relevant here:

> What is the benefit of
>
> 	struct A { void fun(); };
> 	struct B :A {};
>
> 	B b;
> 	b.fun;
>
> compared to
>
> 	struct A {};
> 	struct B { A a; };
>
> 	B b;
> 	b.a.fun;
>

Like, seriously, I might be missing something, but I don't get it.

Can you cite some use case where inheritance is convenient but 
composition isn't? Ideally an actual use case that came up in a 
project?