if (!(x instanceof vCset)) { iRuntime.error(120, x);
vCset right = x.mkCset();   java.util.BitSet bigger; java.util.BitSet smaller; if (right.t.size() < this.t.size()) { bigger = this.t; smaller = right.t; } else { bigger = right.t; smaller = this.t;
vValue Union(vDescriptor x) {    if (!(x instanceof vCset)) {        iRuntime.error(120, x);    }    vCset result = new vCset((java.util.BitSet) ((vCset)x).t.clone());    result.t.or(this.t);    return result;}