// |jit-test| --fast-warmup function foo(o) { return o.x; } with ({}) {} var handler = { get: (target, prop) => { return 1; }, getOwnPropertyDescriptor: (target, prop) => { return Object.getOwnPropertyDescriptor(target, prop); } } var o = {}; Object.defineProperty(o, 'x', { value: 1, configurable: false, writable: false }); var proxy = new Proxy(o, handler); for (var i = 0; i < 50; i++) { foo(proxy); } var proxy_proxy = new Proxy(proxy, handler); foo(proxy_proxy);