function test() {

// Array.prototype.reverse -> Set -> [[Set]]
var set = [];
var p = new Proxy([0,0,0,,], { set: function(o, k, v) { set.push(k); o[k] = v; return true; }});
p.reverse();
return set + '' === "3,1,2";
      
}

if (!test())
    throw new Error("Test failed");