unity创建脚本就断言失败,值为空


AssertionException: Assertion failure. Value was Null
Expected: Value was not Null
UnityEngine.Assertions.Assert.Fail (System.String message, System.String userMessage) (at <7d87237cea3743d093e22c5b98f74fba>:0)
UnityEngine.Assertions.Assert.IsNotNull (UnityEngine.Object value, System.String message) (at <7d87237cea3743d093e22c5b98f74fba>:0)
UnityEngine.Assertions.Assert.IsNotNull[T] (T value, System.String message) (at <7d87237cea3743d093e22c5b98f74fba>:0)
UnityEngine.Assertions.Assert.IsNotNull[T] (T value) (at <7d87237cea3743d093e22c5b98f74fba>:0)
UnityEngine.Rendering.PostProcessing.RuntimeUtilities.get_copyStdMaterial () (at Library/PackageCache/com.unity.postprocessing@2.2.2/PostProcessing/Runtime/Utils/RuntimeUtilities.cs:268)
UnityEngine.Rendering.PostProcessing.PostProcessLayer.BuildCommandBuffers () (at Library/PackageCache/com.unity.postprocessing@2.2.2/PostProcessing/Runtime/PostProcessLayer.cs:605)
UnityEngine.Rendering.PostProcessing.PostProcessLayer.OnPreCull () (at Library/PackageCache/com.unity.postprocessing@2.2.2/PostProcessing/Runtime/PostProcessLayer.cs:440)
UnityEngine.GUIUtility:ProcessEvent(Int32, IntPtr)