Fix playthrough

BaseClasses.py

@@ -1356,21 +1356,19 @@ def create_playthrough(self, create_paths: bool = True) -> None:
 
         # in the second phase, we cull each sphere such that the game is still beatable,
         # reducing each range of influence to the bare minimum required inside it
-        restore_later: Dict[Location, Item] = {}
+        required_locations = {location for sphere in collection_spheres for location in sphere}
         for num, sphere in reversed(tuple(enumerate(collection_spheres))):
             to_delete: Set[Location] = set()
             for location in sphere:
-                # we remove the item at location and check if game is still beatable
+                # we remove the location from required_locations to sweep from, and check if the game is still beatable
                 logging.debug('Checking if %s (Player %d) is required to beat the game.', location.item.name,
                               location.item.player)
-                old_item = location.item
-                location.item = None
-                if multiworld.can_beat_game(state_cache[num]):
+                required_locations.remove(location)
+                if multiworld.can_beat_game(state_cache[num], required_locations):
                     to_delete.add(location)
-                    restore_later[location] = old_item
                 else:
                     # still required, got to keep it around
-                    location.item = old_item
+                    required_locations.add(location)
 
             # cull entries in spheres for spoiler walkthrough at end
             sphere -= to_delete