How to do "inheritance" in D structs

[TheFlyingFiddle via Digitalmars-d-learn]

On Wednesday, 12 October 2016 at 02:18:47 UTC, TheFlyingFiddle 
wrote:
> void foo(ref ABase base)
> {
>     base.ival = 32;
> }
This should be:
void foo(ref Base1 base)
{
     base.ival = 32;
}