| function test() { | |
| var passed = false; | |
| var obj = { foo: true }; | |
| var C = function(){}; | |
| Object.defineProperty(C, Symbol.hasInstance, { | |
| value: function(inst) { passed = inst.foo; return false; } | |
| }); | |
| obj instanceof C; | |
| return passed; | |
| } | |
| if (!test()) | |
| throw new Error("Test failed"); | |