michael@0: load(libdir + "asserts.js");
michael@0: 
michael@0: /*
michael@0:  * Throw a TypeError if the trap reports a non-configurable own property as
michael@0:  * non-existent
michael@0:  */
michael@0: var target = {};
michael@0: Object.defineProperty(target, 'foo', {
michael@0:     configurable: false
michael@0: });
michael@0: var caught = false;
michael@0: assertThrowsInstanceOf(function () {
michael@0:     'foo' in new Proxy(target, {
michael@0:         has: function (target, name) {
michael@0:             return false;
michael@0:         }
michael@0:     });
michael@0: }, TypeError);