Added ChildRemoved connection

lib/instances/BaseInstance.lua

@@ -56,6 +56,10 @@ BaseInstance.properties.ChildAdded = InstanceProperty.readOnly({
 	getDefault = Signal.new
 })
 
+BaseInstance.properties.ChildRemoved = InstanceProperty.readOnly({
+		getDefault = Signal.new
+})
+
 BaseInstance.properties.Parent = InstanceProperty.normal({
 	set = function(self, key, value)
 		local instance = getmetatable(self).instance
@@ -74,6 +78,7 @@ BaseInstance.properties.Parent = InstanceProperty.normal({
 
 		if instance.properties.Parent ~= nil then
 			getmetatable(instance.properties.Parent).instance.children[self] = nil
+			instance.properties.Parent.ChildRemoved:Fire(self)
 		end
 
 		instance.properties.Parent = value

lib/instances/BaseInstance_spec.lua

@@ -671,4 +671,36 @@ describe("instances.BaseInstance", function()
 			assert.spy(spy).was_called_with(child)
 		end)
 	end)
+
+	describe("ChildRemoved", function()
+		it("should fire when a child is destroyed", function()
+			local parent = BaseInstance:new()
+			local child = BaseInstance:new()
+
+			local spy = spy.new(function() end)
+			parent.ChildRemoved:Connect(spy)
+
+			child.Parent = parent
+			assert.spy(spy).was_not_called()
+
+			child:Destroy()
+			assert.spy(spy).was_called_with(child)
+		end)
+
+		it("should fire when a child's parent is set to nil", function()
+			local parent = BaseInstance:new()
+			local child = BaseInstance:new()
+
+			local spy = spy.new(function() end)
+			parent.ChildRemoved:Connect(spy)
+
+			child.Parent = parent
+
+			assert.spy(spy).was_not_called()
+
+			child.Parent = nil
+
+			assert.spy(spy).was_called_with(child)
+		end)
+	end)
 end)