On Wednesday, 21 March 2018 at 11:13:41 UTC, Simen Kjærås wrote:
On Wednesday, 21 March 2018 at 08:49:11 UTC, Mike Franklin
wrote:
I think `rt_finalize` can be made `@nogc` in the runtime.
And this is where you're wrong. Consider this:
class A {
@nogc ~this() {}
}
class B : A {
~this() {}
}
A a = new B();
destroy(a); // Is this @nogc?
Essentially, since @nogc and other qualifiers aren't inherited
on dtors, it's impossible to know if destroying an instance of
a non-final class is @nogc.
There's one case where you can: final classes where no
superclass and no member defines a non-@nogc destructor.
In order for this to be done in the general case, dtors need to
inherit their qualifiers somehow. That's at the very least a
DIP, and any chosen path is highly likely to break existing
code.
--
Simen
You can simply check the .dtor symbols at compile time to see if
every .dtor symbol from child to root have a .dtor that have the
@nogc attribute(and other attributes as well). If it does, add
that attribute to destroy.
