Invalidate removed inventory items

Source/player.cpp

@@ -1937,34 +1937,35 @@ bool Player::HasItem(int item, int *idx) const
 
 void Player::RemoveInvItem(int iv, bool calcScrolls)
 {
-	iv++;
-
 	// Iterate through invGrid and remove every reference to item
-	for (int8_t &itemId : InvGrid) {
-		if (itemId == iv || itemId == -iv) {
-			itemId = 0;
+	for (int8_t &itemIndex : InvGrid) {
+		if (abs(itemIndex) - 1 == iv) {
+			itemIndex = 0;
 		}
 	}
 
-	iv--;
+	InvList[iv]._itype = ItemType::None;
+
 	_pNumInv--;
 
 	// If the item at the end of inventory array isn't the one we removed, we need to swap its position in the array with the removed item
 	if (_pNumInv > 0 && _pNumInv != iv) {
 		InvList[iv] = InvList[_pNumInv];
+		InvList[_pNumInv]._itype = ItemType::None;
 
-		for (int8_t &itemId : InvGrid) {
-			if (itemId == _pNumInv + 1) {
-				itemId = iv + 1;
+		for (int8_t &itemIndex : InvGrid) {
+			if (itemIndex == _pNumInv + 1) {
+				itemIndex = iv + 1;
 			}
-			if (itemId == -(_pNumInv + 1)) {
-				itemId = -(iv + 1);
+			if (itemIndex == -(_pNumInv + 1)) {
+				itemIndex = -(iv + 1);
 			}
 		}
 	}
 
-	if (calcScrolls)
+	if (calcScrolls) {
 		CalcScrolls();
+	}
 }
 
 bool Player::TryRemoveInvItemById(int item)