Instead it seems to just report "unkown" for all wasm frames:
void Foo<int>()")' failed in file /usr/local/google/home/sbc/dev/wasm/emscripten/test/test_emscripten_log.cpp:81!
Callstack was at unknown
at unknown
at unknown
at unknown
at <anonymous> (test_emscripten_log.js:614:12)
at callMain (test_emscripten_log.js:1836:15)
at doRun (test_emscripten_log.js:1889:24)!