michael@0: try {
michael@0:     (function() {
michael@0:         Object.defineProperty(this, "x", {
michael@0:             get: function() {
michael@0:                 Object.defineProperty(this, "y", {
michael@0:                     configurable: true,
michael@0:                     get: function() {
michael@0:                         return Proxy(this.y)
michael@0:                     }
michael@0:                 });
michael@0:                 x;
michael@0:             }
michael@0:         })
michael@0:     })()
michael@0:     x
michael@0: } catch (e) {}
michael@0: try {
michael@0:     x
michael@0: } catch (e) {}
michael@0: try {
michael@0:     x
michael@0: } catch (e) {}
michael@0: try {
michael@0:     y
michael@0: } catch (e) {}
michael@0: try {
michael@0:     y
michael@0: } catch (e) {}
michael@0: try {
michael@0:     y
michael@0: } catch (e) {}