diff --git a/apps/openmw/mwworld/containerstore.cpp b/apps/openmw/mwworld/containerstore.cpp
index c041beffa..4639a1d2d 100644
--- a/apps/openmw/mwworld/containerstore.cpp
+++ b/apps/openmw/mwworld/containerstore.cpp
@@ -77,31 +77,31 @@ MWWorld::ContainerStoreIterator MWWorld::ContainerStore::end()
     return ContainerStoreIterator (this);
 }
 
-bool MWWorld::ContainerStore::stacks(const Ptr& stack, const Ptr& item)
+bool MWWorld::ContainerStore::stacks(const Ptr& ptr1, const Ptr& ptr2)
 {
-    const MWWorld::Class& cls1 = MWWorld::Class::get(stack);
-    const MWWorld::Class& cls2 = MWWorld::Class::get(item);
+    const MWWorld::Class& cls1 = MWWorld::Class::get(ptr1);
+    const MWWorld::Class& cls2 = MWWorld::Class::get(ptr2);
 
     /// \todo add current enchantment charge here when it is implemented
-    return stack != item // an item never stacks onto itself
-        && Misc::StringUtils::ciEqual(stack.getCellRef().mRefID, item.getCellRef().mRefID)
-        && stack.getCellRef().mOwner == item.getCellRef().mOwner
-        && stack.getCellRef().mSoul == item.getCellRef().mSoul
+    return ptr1 != ptr2 // an item never stacks onto itself
+        && Misc::StringUtils::ciEqual(ptr1.getCellRef().mRefID, ptr2.getCellRef().mRefID)
+        && ptr1.getCellRef().mOwner == ptr2.getCellRef().mOwner
+        && ptr1.getCellRef().mSoul == ptr2.getCellRef().mSoul
 
         // item with a script never stacks
-        && cls1.getScript(stack) == ""
-        && cls2.getScript(item) == ""
+        && cls1.getScript(ptr1) == ""
+        && cls2.getScript(ptr2) == ""
 
         // item with enchantment never stacks (we could revisit this later,
         // but for now it makes selecting items in the spell window much easier)
-        && cls1.getEnchantment(stack) == ""
-        && cls2.getEnchantment(item) == ""
+        && cls1.getEnchantment(ptr1) == ""
+        && cls2.getEnchantment(ptr2) == ""
 
         // item that is already partly used up never stacks
-        && (!cls1.hasItemHealth(stack) || stack.getCellRef().mCharge == -1
-            || cls1.getItemMaxHealth(stack) == stack.getCellRef().mCharge)
-        && (!cls2.hasItemHealth(item) || item.getCellRef().mCharge == -1
-            || cls2.getItemMaxHealth(item) == item.getCellRef().mCharge);
+        && (!cls1.hasItemHealth(ptr1) || ptr1.getCellRef().mCharge == -1
+            || cls1.getItemMaxHealth(ptr1) == ptr1.getCellRef().mCharge)
+        && (!cls2.hasItemHealth(ptr2) || ptr2.getCellRef().mCharge == -1
+            || cls2.getItemMaxHealth(ptr2) == ptr2.getCellRef().mCharge);
 }
 
 MWWorld::ContainerStoreIterator MWWorld::ContainerStore::add (const Ptr& itemPtr, const Ptr& actorPtr)
diff --git a/apps/openmw/mwworld/containerstore.hpp b/apps/openmw/mwworld/containerstore.hpp
index 7278135d8..ca6609ecf 100644
--- a/apps/openmw/mwworld/containerstore.hpp
+++ b/apps/openmw/mwworld/containerstore.hpp
@@ -91,7 +91,7 @@ namespace MWWorld
 
         public:
 
-            virtual bool stacks (const Ptr& stack, const Ptr& item);
+            virtual bool stacks (const Ptr& ptr1, const Ptr& ptr2);
             ///< @return true if the two specified objects can stack with each other
 
             void fill (const ESM::InventoryList& items, const std::string& owner, const MWWorld::ESMStore& store);
diff --git a/apps/openmw/mwworld/inventorystore.cpp b/apps/openmw/mwworld/inventorystore.cpp
index 430218058..7bfc11d84 100644
--- a/apps/openmw/mwworld/inventorystore.cpp
+++ b/apps/openmw/mwworld/inventorystore.cpp
@@ -285,9 +285,9 @@ void MWWorld::InventoryStore::flagAsModified()
     mMagicEffectsUpToDate = false;
 }
 
-bool MWWorld::InventoryStore::stacks(const Ptr& stack, const Ptr& item)
+bool MWWorld::InventoryStore::stacks(const Ptr& ptr1, const Ptr& ptr2)
 {
-    bool canStack = MWWorld::ContainerStore::stacks(stack, item);
+    bool canStack = MWWorld::ContainerStore::stacks(ptr1, ptr2);
     if (!canStack)
         return false;
 
@@ -295,7 +295,7 @@ bool MWWorld::InventoryStore::stacks(const Ptr& stack, const Ptr& item)
     for (TSlots::const_iterator iter (mSlots.begin());
         iter!=mSlots.end(); ++iter)
     {
-        if (*iter != end() && (stack == **iter || item == **iter))
+        if (*iter != end() && (ptr1 == **iter || ptr2 == **iter))
         {
             bool stackWhenEquipped = MWWorld::Class::get(**iter).getEquipmentSlots(**iter).second;
             if (!stackWhenEquipped)
diff --git a/apps/openmw/mwworld/inventorystore.hpp b/apps/openmw/mwworld/inventorystore.hpp
index a974c0dae..b7d374824 100644
--- a/apps/openmw/mwworld/inventorystore.hpp
+++ b/apps/openmw/mwworld/inventorystore.hpp
@@ -107,7 +107,7 @@ namespace MWWorld
             ///< \attention This function is internal to the world model and should not be called from
             /// outside.
 
-            virtual bool stacks (const Ptr& stack, const Ptr& item);
+            virtual bool stacks (const Ptr& ptr1, const Ptr& ptr2);
             ///< @return true if the two specified objects can stack with each other
 
             virtual int remove(const Ptr& item, int count, const Ptr& actor);