diff --git a/worlds/witness/__init__.py b/worlds/witness/__init__.py
index b4b38c883e7d..c9848f2ffe47 100644
--- a/worlds/witness/__init__.py
+++ b/worlds/witness/__init__.py
@@ -14,7 +14,7 @@
 from .data import static_locations as static_witness_locations
 from .data import static_logic as static_witness_logic
 from .data.item_definition_classes import DoorItemDefinition, ItemData
-from .data.utils import get_audio_logs
+from .data.utils import cast_not_none, get_audio_logs
 from .hints import CompactHintData, create_all_hints, make_compact_hint_data, make_laser_hints
 from .locations import WitnessPlayerLocations
 from .options import TheWitnessOptions, witness_option_groups
@@ -55,7 +55,7 @@ class WitnessWorld(World):
 
     item_name_to_id = {
         # ITEM_DATA doesn't have any event items in it
-        name: cast(int, data.ap_code) for name, data in static_witness_items.ITEM_DATA.items()
+        name: cast_not_none(data.ap_code) for name, data in static_witness_items.ITEM_DATA.items()
     }
     location_name_to_id = static_witness_locations.ALL_LOCATIONS_TO_ID
     item_name_groups = static_witness_items.ITEM_GROUPS
@@ -336,7 +336,7 @@ def fill_slot_data(self) -> Dict[str, Any]:
             for item_name, hint in laser_hints.items():
                 item_def = cast(DoorItemDefinition, static_witness_logic.ALL_ITEMS[item_name])
                 self.laser_ids_to_hints[int(item_def.panel_id_hexes[0], 16)] = make_compact_hint_data(hint, self.player)
-                already_hinted_locations.add(cast(Location, hint.location))
+                already_hinted_locations.add(cast_not_none(hint.location))
 
         # Audio Log Hints
 
diff --git a/worlds/witness/data/utils.py b/worlds/witness/data/utils.py
index 84eca5afc43f..737daff70fae 100644
--- a/worlds/witness/data/utils.py
+++ b/worlds/witness/data/utils.py
@@ -1,7 +1,7 @@
 from math import floor
 from pkgutil import get_data
 from random import Random
-from typing import Any, Collection, Dict, FrozenSet, Iterable, List, Set, Tuple, TypeVar
+from typing import Any, Collection, Dict, FrozenSet, Iterable, List, Optional, Set, Tuple, TypeVar
 
 T = TypeVar("T")
 
@@ -13,6 +13,11 @@
 WitnessRule = FrozenSet[FrozenSet[str]]
 
 
+def cast_not_none(value: Optional[T]) -> T:
+    assert value is not None
+    return value
+
+
 def weighted_sample(world_random: Random, population: List[T], weights: List[float], k: int) -> List[T]:
     positions = range(len(population))
     indices: List[int] = []
diff --git a/worlds/witness/player_items.py b/worlds/witness/player_items.py
index 72dfc2b7ee54..4c98cb78495e 100644
--- a/worlds/witness/player_items.py
+++ b/worlds/witness/player_items.py
@@ -15,7 +15,7 @@
     ProgressiveItemDefinition,
     WeightedItemDefinition,
 )
-from .data.utils import build_weighted_int_list
+from .data.utils import build_weighted_int_list, cast_not_none
 from .locations import WitnessPlayerLocations
 from .player_logic import WitnessPlayerLogic
 
@@ -200,7 +200,7 @@ def get_symbol_ids_not_in_pool(self) -> List[int]:
         """
         return [
             # data.ap_code is guaranteed for a symbol definition
-            cast(int, data.ap_code) for name, data in static_witness_items.ITEM_DATA.items()
+            cast_not_none(data.ap_code) for name, data in static_witness_items.ITEM_DATA.items()
             if name not in self.item_data.keys() and data.definition.category is ItemCategory.SYMBOL
         ]
 
@@ -211,8 +211,8 @@ def get_progressive_item_ids_in_pool(self) -> Dict[int, List[int]]:
             if isinstance(item.definition, ProgressiveItemDefinition):
                 # Note: we need to reference the static table here rather than the player-specific one because the child
                 # items were removed from the pool when we pruned out all progression items not in the options.
-                output[cast(int, item.ap_code)] = [cast(int, static_witness_items.ITEM_DATA[child_item].ap_code)
-                                                   for child_item in item.definition.child_item_names]
+                output[cast_not_none(item.ap_code)] = [cast_not_none(static_witness_items.ITEM_DATA[child_item].ap_code)
+                                                       for child_item in item.definition.child_item_names]
         return output
 
 
diff --git a/worlds/witness/test/__init__.py b/worlds/witness/test/__init__.py
index 4453609ddcdb..c3b427851af0 100644
--- a/worlds/witness/test/__init__.py
+++ b/worlds/witness/test/__init__.py
@@ -1,4 +1,4 @@
-from typing import Any, ClassVar, Dict, Iterable, List, Mapping, Union, cast
+from typing import Any, ClassVar, Dict, Iterable, List, Mapping, Union
 
 from BaseClasses import CollectionState, Entrance, Item, Location, Region
 
@@ -7,6 +7,7 @@
 from test.multiworld.test_multiworlds import MultiworldTestBase
 
 from .. import WitnessWorld
+from ..data.utils import cast_not_none
 
 
 class WitnessTestBase(WorldTestBase):
@@ -32,7 +33,7 @@ def assert_dependency_on_event_item(self, spot: Union[Location, Region, Entrance
         event_items = [item for item in self.multiworld.get_items() if item.name == item_name]
         self.assertTrue(event_items, f"Event item {item_name} does not exist.")
 
-        event_locations = [cast(Location, event_item.location) for event_item in event_items]
+        event_locations = [cast_not_none(event_item.location) for event_item in event_items]
 
         # Checking for an access dependency on an event item requires a bit of extra work,
         # as state.remove forces a sweep, which will pick up the event item again right after we tried to remove it.