This test for a crash when optimizing expressions of the form 'typeof o == constant' where 'constant' is not a string. On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE". PASS typeof o == undefined is false PASS typeof o == null is false PASS typeof o == true is false PASS typeof o == false is false PASS typeof o == 1 is false PASS typeof o == 1.0 is false PASS typeof o == { } is false PASS successfullyParsed is true TEST COMPLETE