ASSERT_UNUSED(globalData, globalData->identifierTable == currentIdentifierTable());

in Identifier.cpp:253

Happens with qt5 and qt6, with qbs and qmake builds and also with the v5.15.2 tag in QtScript.
It is not clear why this doesn't happen when using prebuilt QtScript (yes, the assert is disabled in release, but the code crashes in release version too with builtin qtscript, just in different place but also related to currentIdentifierTable()).