# V3215. Unity Engine. Passing a method name as a string literal into the 'StartCoroutine' is unreliable.

The analyzer has detected that a string literal is passed as an argument to the `Invoke`, `InvokeRepeating`, `CancelInvoke`, `StartCoroutine`, or `StopCoroutine` methods of the `UnityEngine.MonoBehaviour` class, which is unreliable. If the passed string literal no longer corresponds to the method for some reason—in particular, if the method changes its name or becomes unavailable—the call will be ignored without any notification.

The example:

    public class CoroutineAndInvoke : MonoBehaviour
    {
      void Start()
      {
        Invoke("CreateEnemyMethod", 1f);
        StartCoroutine("DangerCheckCoroutine");
      }

      private void CreateEnemyMethod()
      {
        ....
      }

      private IEnumerator DangerCheckCoroutine()
      {
        ....
      }
    }

In this case, the `Invoke` and `StartCoroutine` methods are called with string literals that correspond to the existing methods, `CreateEnemyMethod` and `DangerCheckCoroutine`. The script works correctly, but reliability is broken. As the result, the analyzer issues a level 3 warning.

To maintain reliability when calling these methods, use `nameof` to retrieve the method name. If you use `StartCoroutine`, call the coroutine directly.

The example with the maintained reliability:

    public class CoroutineAndInvoke : MonoBehaviour
    {
      void Start()
      {
        Invoke(nameof(CreateEnemyMethod), 1f);
        StartCoroutine(DangerCheckCoroutine());
      }
      ....
    }

In this case, passing a non-existent method as an argument is prevented. Another advantage of using `nameof` and direct coroutine calls is the ability to rename methods during refactoring. The changes automatically update the arguments of the `Invoke` and `StartCoroutine` methods.

Here is an example where string literals do not correspond to the methods:

    public class CoroutineAndInvoke : MonoBehaviour
    {
      void Start()
      {
        Invoke("CreateEnemy", 1f);
        StartCoroutine("DangerCheck");
      }

      private void CreateEnemyMethod()
      {
        ....
      }

      private IEnumerator DangerCheckCoroutine()
      {
        ....
      }
    }

In this case, the `Invoke` and `StartCoroutine` methods are ignored because no methods corresponding to the passed string literals are detected. The analyzer issues a level 1 warning. Such an error can occur, for example, due to a typo when writing the method name in the argument or when renaming the method.

This diagnostic is classified as:

CWE-1106