Eating/drinking an item with multiple effects can trigger NULL pointer dereference in obj_nourishes()

[backwardsEric]

That happens if the player's hunger meter is greater than or equal to PY_FOOD_MAX and one of the object's effects before the nourish effect does not have a dice expression associated with it. For instance, Orcish Liquor has the cure fear effect (with no dice expression) before the nourish effect.