Method backward_barrier

aiscript-arena/src/context.rs:43–48

(&self, parent: Gc<'gc, ()>, child: Option<Gc<'gc, ()>>)

    /// pointer(s) before collection is next triggered.
    #[inline]
    pub fn backward_barrier(&self, parent: Gc<'gc, ()>, child: Option<Gc<'gc, ()>>) {
        self.context.backward_barrier(
            unsafe { GcBox::erase(parent.ptr) },
            child.map(|p| unsafe { GcBox::erase(p.ptr) }),
        )
    }

    /// IF we are in the marking phase AND the `parent` pointer (if given) is colored black, AND
    /// the `child` is colored white, then immediately change the `child` to gray and enqueue it