Fix bug in item loc when combining items, rethink centralizing item locs

src/Dodge/Inventory/Location.hs

@@ -15,6 +15,8 @@ import Dodge.Item.Grammar
 import Data.Maybe
 import Control.Applicative
 
+ -- this assumes the creature inventory is well formed, specifically the
+ -- location ids
 tryGetRootItemInvID :: Int -> Creature -> Maybe Int
 tryGetRootItemInvID i cr = do
     let adj = case invAdj' (_crInv cr) of
@@ -39,7 +41,7 @@ crUpdateItemLocations  crid lw = fromMaybe lw $ do
 crUpdateInvidLocations :: ManipulatedObject -> Int -> LWorld -> Int -> Item -> LWorld
 crUpdateInvidLocations mo crid lw invid itm = lw
     & creatures . ix crid . crInv . ix invid . itLocation .~ newloc
-    & itemLocations . ix itid .~ newloc
+    & itemLocations %~ IM.insert itid newloc
   where
     itid = itm ^. itID
     newloc = InInv crid invid (Just invid == mo ^? inInventory . imSelectedItem)