#endif
} else if (block->signal_type_to_connect == Block::CONNECT_VIDEO) {
signals_to_connect.emplace(input, block->video_to_connect->get_card_index());
+ } else if (block->signal_type_to_connect == Block::CONNECT_NONE) {
+ luaL_error(L, "An input in a chain was not connected to anything (forgot to call display())");
} else {
assert(false);
}