TreeModelFilter generateArtistFilter(in string artistName) {
        static string* s_an = artistName.ptr;   // Error: variable artistName cannot be read at compile time
        // nested private function
        static extern (C) int fn(GtkTreeModel* m, GtkTreeIter* i, void* data) {
            TreeModel model_ = new TreeModel(m);
            TreeIter iter = new TreeIter(i);

            string name = model_.getValue(iter, COLUMNS.ARTIST).getString();
            return name == *s_an;
        }

        auto filter = new TreeModelFilter(model, null);
        filter.setVisibleFunc(&fn, null, cast(GDestroyNotify) null);
        return filter;
    }