How to find all colliders below mouse?

 public static bool IsTopmost(GameObject go)
     {
         RaycastHit[] hits;
         Vector3 wp = Camera.main.ScreenToWorldPoint(Input.mousePosition);
         wp.z = Camera.main.transform.position.z;
         hits = Physics.RaycastAll(wp, Vector3.forward, Vector3.Distance(Camera.main.transform.position, go.transform.position) * 2);
 
         if (hits.Length == 0)
         {
             return false;
         }
 
         GameObject topMostSoFar = hits[0].collider.gameObject;
 
         RaycastHit hit;
         for (int i = 1; i < hits.Length; i++)
         {
             hit = hits[i];
 
             if (Compare(topMostSoFar, hit.collider.gameObject) == -1)
             {
                 topMostSoFar = hit.collider.gameObject;
             }
         }
 
         Debug.Log("finishes method");
         return topMostSoFar.name == go.name;
     }

My camera position.z = -5, all sprites in the game position.z = 0. This method never finishes, it always enters the first if which says there are no colliders under the mouse position. What do I do wrong here?

EDIT: It turns out my mistake is very stupid, I'm using Physics instead of Physics2D for 2d colliders. How can I check same thing but with 2d raycasting?