Thanks for the report. This is a faulty assert(), so it is harmless in production builds where assert() statements are omitted. The fix is at [check-in 240f7494bfa3][1]. There was a similar bug fixed at [check-in 59812e7ef705226c][2]. [1]: src:/info/240f7494bfa3 [2]: src:/info/59812e7ef705226c