regex_match("", regex("(?:)*") will cause segfault because the infinite loop detection (writeen by me) is stupid. :O
Instead of checking begins and ends, now the executor tracks repeating count for every loop node (typically generated from the Kleene star *). It slows down the executor a bit (from 1.8s to 2.0s in my machine), but it's about the correctness. The whole patch series are booted and tested, but this one is not separately tested. Thanks! -- Regards, Tim Shen