- Add proper try/catch compilation (PushExceptionHandler/PopExceptionHandler bytecode ops) — previously try/catch was a stub that compiled blocks sequentially without exception handling - Add function property support (functions are objects in JS and can have arbitrary properties like assert.sameValue) - Implement Test262 harness preamble with assert, assert.sameValue, assert.notSameValue, assert.throws, and Test262Error helpers - Add evaluate_with_preamble API for running tests with harness globals - Add instruction limit to VM to prevent infinite loops in test suite - Implement test metadata parsing (features, flags, includes, negative tests) - Add feature-based test skipping for unimplemented features - Report pass/fail/skip grouped by category with pass rate percentages Initial pass rate: 3406/8929 executed (38%), 14455 skipped. Notable: keywords 100%, punctuators 100%, ASI 95%, block-scope 88%. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>