michael@0: Function.prototype.X = 42;
michael@0: function ownProperties() {
michael@0:     var props = {};
michael@0:     var r = function () {};
michael@0:     for (var a in r) {
michael@0:         let (a = function() { for (var r=0;r<6;++r) ++a; }) {
michael@0:             a();
michael@0:         }
michael@0:         props[a] = true;
michael@0:     }
michael@0: }
michael@0: ownProperties();