diff --git a/exp_gui/module/control.lua b/exp_gui/module/control.lua
index 56cf2dd3..c6f84e3c 100644
--- a/exp_gui/module/control.lua
+++ b/exp_gui/module/control.lua
@@ -88,7 +88,7 @@ end
 --- @param define ExpElement
 --- @param visible Gui.VisibleCallback | boolean | nil
 function Gui.add_top_element(define, visible)
-    assert(Gui.top_elements[define.name] == nil, "Element is already added to the top flow")
+    assert(Gui.top_elements[define] == nil, "Element is already added to the top flow")
     Gui.top_elements[define] = visible or false
 end
 
@@ -96,7 +96,7 @@ end
 --- @param define ExpElement
 --- @param visible Gui.VisibleCallback | boolean | nil
 function Gui.add_left_element(define, visible)
-    assert(Gui.left_elements[define.name] == nil, "Element is already added to the left flow")
+    assert(Gui.left_elements[define] == nil, "Element is already added to the left flow")
     Gui.left_elements[define] = visible or false
 
 end
@@ -105,7 +105,7 @@ end
 --- @param define ExpElement
 --- @param visible Gui.VisibleCallback | boolean | nil
 function Gui.add_relative_element(define, visible)
-    assert(Gui.relative_elements[define.name] == nil, "Element is already added to the relative flow")
+    assert(Gui.relative_elements[define] == nil, "Element is already added to the relative flow")
     Gui.relative_elements[define] = visible or false
 end
 
diff --git a/exp_gui/module/data.lua b/exp_gui/module/data.lua
index d57c8c99..3e92cd14 100644
--- a/exp_gui/module/data.lua
+++ b/exp_gui/module/data.lua
@@ -90,13 +90,16 @@ function GuiData._metatable.__index(self, key)
     assert(type(key) == "userdata", "Index type '" .. ExpUtil.get_class_name(key) .. "' given to GuiData. Must be of type userdata.")
     local object_name = key.object_name --- @diagnostic disable-line assign-type-mismatch
     if object_name == "LuaGuiElement" then
+        --- @cast key LuaGuiElement
         local data = self._raw.element_data
         local player_elements = data and data[key.player_index]
         return player_elements and player_elements[key.index]
     elseif object_name == "LuaPlayer" then
+        --- @cast key LuaPlayer
         local data = self._raw.player_data
         return data and data[key.index]
     elseif object_name == "LuaForce" then
+        --- @cast key LuaForce
         local data = self._raw.force_data
         return data and data[key.index]
     else
diff --git a/exp_gui/module/iter.lua b/exp_gui/module/iter.lua
index 9d8db2ea..ad1d609c 100644
--- a/exp_gui/module/iter.lua
+++ b/exp_gui/module/iter.lua
@@ -166,7 +166,6 @@ end
 function GuiIter.get_tracked_elements(scope, filter)
     local class_name = ExpUtil.get_class_name(filter)
     if class_name == "nil" then
-        --- @cast filter nil
         return GuiIter.all_elements(scope)
     elseif class_name == "LuaPlayer" then
         --- @cast filter LuaPlayer
@@ -189,7 +188,6 @@ end
 function GuiIter.get_online_elements(scope, filter)
     local class_name = ExpUtil.get_class_name(filter)
     if class_name == "nil" then
-        --- @cast filter nil
         return GuiIter.filtered_elements(scope, game.connected_players)
     elseif class_name == "LuaPlayer" then
         --- @cast filter LuaPlayer
@@ -235,7 +233,7 @@ end
 function GuiIter.remove_element(scope, player_index, element_index)
     local scope_elements = registered_scopes[scope]
     if not scope_elements then return end
-    local player_elements = registered_scopes[player_index]
+    local player_elements = scope_elements[player_index]
     if not player_elements then return end
     player_elements[element_index] = nil
 end
diff --git a/exp_gui/module/toolbar.lua b/exp_gui/module/toolbar.lua
index f22c4cc7..a1f438db 100644
--- a/exp_gui/module/toolbar.lua
+++ b/exp_gui/module/toolbar.lua
@@ -350,7 +350,7 @@ local function move_toolbar_button(player, item, offset)
 
     -- Swap the position in the list
     local list = assert(item.parent)
-    local other_item = list.children[new_index]
+    local other_item = assert(list.children[new_index])
     list.swap_children(old_index, new_index)
 
     -- Swap the position in the top flow, offset by 1 because of settings button
@@ -499,7 +499,8 @@ function Toolbar._create_elements(player)
     -- Reset the state of the previous last child
     local children = toolbar_list.children
     if previous_last_index > 0 then
-        elements.toolbar_list_item.data[children[previous_last_index]].move_item_down.enabled = true
+        local previous_last = assert(children[previous_last_index])
+        elements.toolbar_list_item.data[previous_last].move_item_down.enabled = true
     end
 
     -- Set the state of the move buttons for the first and last element