@beta i'm curious, as well. i've temporarily increased my stack size so that i can finish what i'm working on, but that's not a solution i'd like to have to ship. it happens in the same place in linux and osx, and with different versions of the language, but so far it only happens when i run tests, so it is possible the testing framework is somehow setting things up in a way that triggers it, but that being the solution requires more faith than i have. i can also easily rewrite this code to be iterative instead of recursive, but that feels a bit like giving up too early. i'll definitely pass along anything i find that might be useful! thanks for inquiring!