function testInt32ToId() { // Ensure that a property which is a negative integer that does not fit in a // jsval is properly detected by the 'in' operator. var obj = { "-1073741828": 17 }; var index = -1073741819; var a = []; for (var i = 0; i < 10; i++) { a.push(index in obj); index--; } // Ensure that a property which is a negative integer that does not fit in a // jsval is properly *not* detected by the 'in' operator. In this case // wrongly applying INT_TO_JSID to -2147483648 will shift off the sign bit // (the only bit set in that number) and bitwise-or that value with 1, // producing jsid(1) -- which actually represents "0", not "-2147483648". // Thus 'in' will report a "-2147483648" property when none exists, because // it thinks the request was really whether the object had property "0". var obj2 = { 0: 17 }; var b = []; var index = -(1 << 28); for (var i = 0; i < 10; i++) { b.push(index in obj2); index = index - (1 << 28); } return a.join(",") + b.join(","); } assertEq(testInt32ToId(), "false,false,false,false,false,false,false,false,false,true" + "false,false,false,false,false,false,false,false,false,false");