Checking if a point is inside a Collider

Hello. I am following Unity docs and want to Checking if a point is inside a Collider.
There is an example code:

Code (CSharp):

1. public class Example : SystemBase
2. {
3.    protected override void OnUpdate()
4.    {
5.        // Fetch the PhysicsWorld through the PhysicsWorldSystem
6.        var worldSystem = World.GetExistingSystem<PhysicsWorldSystem>();
7.        var physicsWorld = worldSystem.PhysicsWorld;
8.  
9.        // Create an input object to define the point data
10.        var point = new OverlapPointInput()
11.        {
12.            Position = float2.zero,
13.            Filter = CollisionFilter.Default
14.        };
15.  
16.        // Check if any of the colliders in the world are overlapping the point
17.        if (physicsWorld.OverlapPoint(point))
18.        {
19.            // Hit!
20.        }
21.    }
22. }
23.  

But what is the PhysicsWorldSystem, OverlapPointInput and CollisionFilter? Its highlightes with red line in VisualStudio and Alt+Enter doestn give any suggestion.

 

You are probably missing the Unity Physics package. (https://docs.unity3d.com/Packages/com.unity.physics@0.5/manual/index.html)
Or you have in in editor but did not reference it in your assembly definition.