Object.prototype.watch.call(1, Symbol(), function() {}) asserts js debug shell on m-c changeset 06e9a27a6fcc without any CLI arguments at Assertion failure: JSID_IS_STRING(id) || JSID_IS_INT(id), at jswatchpoint.cpp My configure flags are: CC="clang -Qunused-arguments" CXX="clang++ -Qunused-arguments" AR=ar sh /Users/skywalker/trees/mozilla-central/js/src/configure --target=x86_64-apple-darwin12.5.0 --enable-debug --enable-optimize --enable-profiling --enable-gczeal --enable-debug-symbols --disable-tests --enable-more-deterministic --with-ccache --enable-threadsafe <other NSPR options> === Tinderbox Build Bisection Results by autoBisect === The "good" changeset has the timestamp "20140623115045" and the hash "611283da02bf". The "bad" changeset has the timestamp "20140623122048" and the hash "cd2894ed2c76". Likely regression window: https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=611283da02bf&tochange=cd2894ed2c76 Jason, is bug 645416 a likely regressor?

It's definitely the regressor.

Jeff, I'd like to sneak this in before the train departs, if possible. Bogus assertions; all the machinery underneath just compares jsids using ==, which works the same for symbols as for PropertyKeys and indexes.

Pressure's off for FF33; there are enough minor bugs that I'm going to push Symbols out a release (see bug 1041631).