控制台中无法识别Unity c#错误四元数

我得到一个错误，说“四元数”是无法识别的

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour
{
    public GameObject prefab;

    // Instantiate the Prefab somewhere between -10.0 and 10.0 on the x-z plane
    void Start()
    {
        Vector3 position = new Vector3(Random.Range(-10.0f, 10.0f), 0, Random.Range(-10.0f, 10.0f));
        Instantiate(prefab, position, quaternion.identity);
    }
}

“四元数”中的q需要大写才能清除错误。

四元数中的q需要大写才能清除错误