"Cannot implicitly convert type 'UnityEngine.Collider[]' to 'bool'"

I’m trying to implement a frag grenade into my FPS. I want it so that the barrels will be affect by force then explode and add 1 to the player’s score. This is the part of code with the error.

	IEnumerator DelayedExplosion(float delay)
	{
				{
					yield return new WaitForSeconds (delay);
						Instantiate (fragExplosion, grenade.transform.position,
			             Quaternion.identity);
						grenade.SetActive (false);
						audio.clip = grenadeExplosion;
						audio.Play ();
							Vector3 explosionPos = grenade.transform.position;
						    Collider colliders = Physics.OverlapSphere (explosionPos, radius);
							foreach(Collider hit in colliders)
								{
									 if(Physics.OverlapSphere (explosionPos, radius)){ 
										if (hit.collider.gameObject.tag == "Target"){ 
											Debug.Log ("Hit" + hit.collider.gameObject.name);
											TargetScript targetScript =
												hit.collider.gameObject.GetComponent<TargetScript> ();
											if (targetScript != null) {
												targetScript.HitApplyForce(grenade.transform.position, 100f);
						}

						GameObject playerScript = GameObject.Find ("Player");
						{
							
							PlayerScript Playerscript
								= playerScript.GetComponent<PlayerScript>();
										
									Playerscript.score++;

								}
					}
						yield return new WaitForSeconds (audio.clip.length);
						yield return new WaitForSeconds (0.5f);
				
				}
			}

		}
		StopCoroutine ("DelayedExplosion");
	}

It’s because Pysics.OvelapSphere returns an array and you are trying to use it as a bool

 if(Physics.OverlapSphere (explosionPos, radius))

Also, aren’t you doing that same OverlapSphere just 3 rows before that ? Then you do the same check for all colliders inside the collider list you get as a result. The code doesn’t make any sense to me.

Collider[] colliders = Physics.OverlapSphere (explosionPos, radius);
foreach(Collider hit in colliders)
{
    if(Physics.OverlapSphere (explosionPos, radius)) {...

It should probably be something like

Collider colliders = Physics.OverlapSphere (explosionPos, radius);
if (colliders != null)
{
    foreach (Collider hit in colliders)
    {
        ...