报错问题UNITY_MATRIX_MVP和UnityObject

v2f vert(appdata v)
{
v2f o;
//unity5.6以前的写法
//o.vertex = mul(UNITY_MATRIX_MVP,v.vertex);

//unity5.6以后的写法
 o.vertex = UnityObjectToClipPos(v.vertex);
 
return o;  

}