Can we just have struct inheritence already?

[H. S. Teoh]

On Mon, Jun 10, 2019 at 06:35:16PM -0400, Nick Sabalausky (Abscissa) via Digitalmars-d wrote:
> On 6/10/19 12:03 AM, Nicholas Wilson wrote:
> > On Monday, 10 June 2019 at 03:08:26 UTC, Walter Bright wrote:
> > > On 6/9/2019 12:40 PM, Vladimir Panteleev wrote:
> > > > Structs are always at least 1 byte in size, even when they
> > > > contain no fields. This causes unnecessary bloat for reasons
> > > > that I never understood.
> > > 
> > > 
> > > The reason is so that each struct instance is at a unique address.
> > > 
> > > There are some rules in C++ where sometimes a struct with no
> > > fields occupies 1 byte, sometimes 0 bytes. I don't recall what
> > > they are at the moment.
> > 
> > There is a (proposal?) for a no unique address attribute to
> > disappear the address of structs the take up no room.
> 
> Would it really be a problem for the addresses of zero-byte structs to
> just simply be null?

Probably, if people expect:

	struct S {}
	S s;
	assert(&s !is null);

to work.

TBH, though, expecting different instances of a 0-sized struct to have
distinct addresses is kind of a strange obscure case, and I'm not
convinced it's worth the resulting slew of messy special cases just to
cater to it.  But that ship has long since sailed, and I'm not sure it's
worth fighting over anymore.


T

-- 
Chance favours the prepared mind. -- Louis Pasteur