On Wednesday, 29 July 2015 at 21:33:16 UTC, remi thebault wrote:
Hello
I have this weird error trying to achieve something simple:
That's far from simple.
Here's a reduction:
----
template wl_container_of(alias member)
{
size_t get() {return member.offsetof;}
}
struct item { int link; }
void main()
{
wl_container_of!(item.link).get(); /* Error: 'this' is only
defined in non-static member functions, not main */
}
----
I'm not sure what's going on here, if this should or shouldn't
work. The error message isn't exactly good.
Slapping `static` on `get` seems to make it work:
----
static size_t get() {return member.offsetof;}
----
I guess the compiler thinks that since `item.link` is an instance
member, it needs a `this`. And then `get` would need a `this` too
as it's using `item.link` via `member`. When the compiler sees
that there is no `this`, it errors out.
An explicit `static` forces the compiler to assume no `this`. And
it would error out if you actually tried to make use of it.
Naively, I'd think the compiler should be able to figure that out
itself.
