I have this error in 2021.1.17f1

I have this error with a simple stop coroutine in 2020.2.0f1

Same problem in Unity 2019.4.11f1

still coming in unity 2019.2.18f1 but solved by this->

private IEnumerator TimerEnumerator;

public void StartCoroutineTimer(int time)
{
TimerEnumerator = Timer(time); // Timer is coroutine
StartCoroutine(TimerEnumerator);
}

public void StopCoroutineTimer()
{
StopCoroutine(TimerEnumerator);
}

call StartCoroutineTimer to start and StopCoroutineTimer to stop.

Happening here in 2019.1.14f1

Seeing it again in Unity 2019.1.9f1! damn irritating :(

Error still persist in Unity 2019.1.9f1 :D :D :D This is not serious...

Still error in Unity 5.6.4f1-64bit
But you can use like that:

public class Test : MonoBehaviour {

Coroutine coroutine;
// Use this for initialization
void Start () {
coroutine = StartCoroutine(Coroutine_1());
}

private IEnumerator Coroutine_1()
{
yield return new WaitForEndOfFrame();
StopCoroutine(coroutine);
yield return new WaitForEndOfFrame();
Debug.Log("Test");
}
}

Error still persist in Unity 5.4.3

Error in Unity 5.3.4f1
public void StartInstantiate(){
StopInstantiate ();
coroutine = IEInstantiate ();
StartCoroutine (coroutine);
}

private void StopInstantiate(){
if (coroutine != null)
StopCoroutine (coroutine);
coroutine = null;
}