ObjectSpace::WeakMap#[]=

static VALUE
wmap_aset(VALUE self, VALUE key, VALUE value)
{
    struct weakmap *w;

    TypedData_Get_Struct(self, struct weakmap, &weakmap_type, w);
    if (FL_ABLE(value)) {
        define_final0(value, w->final);
    }
    if (FL_ABLE(key)) {
        define_final0(key, w->final);
    }

    st_update(w->obj2wmap, (st_data_t)value, wmap_aset_update, key);
    st_insert(w->wmap2obj, (st_data_t)key, (st_data_t)value);
    return nonspecial_obj_id(value);
}