{
t = get_thing(world.things, id, 1);
char * err = "No thing type found to initialize new thing.";
- if (!t && !err_line(NULL == world.thing_types, err))
+ if (!t && !err_line(!world.thing_types, err))
{
t = add_thing(id, world.thing_types->id, 0, 0);
if (world.exists && t->lifepoints)