Reload scene when dead

Application.LoadLevel() is now obsolete, so you should use SceneManager.LoadScene() instead. You can pass in an argument of SceneManager.GetActiveScene() to just reload the current scene.

Note that unlike the Application class, the SceneManager class is not directly in UnityEngine, so you'll need to add this line to your imports at the top of your source file: using UnityEngine.SceneManagement;.

In Unity 5.0 and later

 // place this at the top of your file
 using UnityEngine.SceneManagement;

 // then call this to restart game
 void hardRestartGame() {
     SceneManager.LoadScene(SceneManager.GetActiveScene().name);
 }

Unity 2019.4 Edit: This is C# Edit 2: also have the script named "TriggerControl" otherwise it's gonna give you an error This is really late but I just want to post this, put this script in to the object that you want to reload the scene when the player and the object collide, make sure the player or the object have a rigidbody.

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.SceneManagement;
 
 public class TriggerControl : MonoBehaviour
 {
    private void OnCollisionEnter(Collision other)
    {
         if (other.gameObject.tag == "Player")
         SceneManager.LoadScene(SceneManager.GetActiveScene().buildIndex);
    }
 }

I had this problem too. I wanted to destroy the player object and than restart the scene, but then i realized, that i was calling the code from object that was already destroyed. So just create empty object and attach the code to it. Hope this might help someone :)