Why is "player" not recognized?

I wrote a bit of code to make an animation when the player dies but it says player isn’t recognized in this code (line 12 (out of the lines with words))

private PlayerController player;

public IEnumerator RespawnPlayerCo()
{
Instantiate (deathParticle, player.transform.position, player.transform.rotation);
player.enabled = false;

	player.GetComponent<Renderer>().enabled = false;

	Debug.Log ("Player Respawn");

	yield return new WaitForSeconds (respawnDelay);

	player.transform.position = currentCheckpoint.transform.position;

	player.enabled = true

	player.GetComponent<Renderer>().enabled = true

	Instantiate (respawnParticle, currentCheckpoint.transform.position, currentCheckpoint.transform.rotation);

  }

player controller is this another script that controls the player.
a. What is the problem?
b. How can I fix this?

It seems you forgot a semicolon between “player.enabled = true” and “player.GetComponent().enabled = true” and also “Instantiate (respawnParticle, currentCheckpoint.transform.position, currentCheckpoint.transform.rotation);”

I guess your code should look like

private PlayerController player;

public IEnumerator RespawnPlayerCo() {
    Instantiate (deathParticle, player.transform.position, player.transform.rotation);
    player.enabled = false;
    player.GetComponent().enabled = false;
    Debug.Log ("Player Respawn");
    yield return new WaitForSeconds (respawnDelay);
    player.transform.position = currentCheckpoint.transform.position;
    player.enabled = true;
    player.GetComponent().enabled = true;
    Instantiate (respawnParticle, currentCheckpoint.transform.position, currentCheckpoint.transform.rotation);
}

So there are your missing semicolons, on the two last lines before the last Instantiate.