Recent changes to op_instanceof and op_construct in r36417 and r36427 mean that exception data is not correctly emitted for op_instanceof and op_construct. An op_get_by_id is emitted to get the prototype property ahead of time, but there is no exception data for these new opcodes. This shouldn't be too hard to fix: just make these opcodes use ThrowableSubExpressionData and emit the right information.
Created attachment 23519 [details] Proposed patch for 'instanceof' case Here's a patch for the 'instanceof' case. The constructor case requires actual subexpression data, but I should be able to do it easily after figuring out this case.
Created attachment 23520 [details] Proposed patch for 'instanceof' case Oops. Here is the version with the layout test changes as well.
Comment on attachment 23520 [details] Proposed patch for 'instanceof' case r- as this reduces the fidelity of the error messages, and the error range no longer covers the entire instanceof
Created attachment 23521 [details] Proposed patch This patch fixes both cases, and it does not change any of the exception information at all.
Comment on attachment 23521 [details] Proposed patch r=me
Landed in r36604.