Unable to initialize arrays or lists.

So I'm trying to make either an array or a list which would hold Vector2 elements. Those containers ideally would be able to be sent to objects. But I can't even get to that part. The arrays and lists refuse to initialize. For example:

 using UnityEngine;
 using System.Collections;
 using System.Collections.Generic;
 
 public class Test : MonoBehaviour {
 
     // Use this for initialization
     void Start () {
         List<Vector2> pathTaken = new List<Vector2> ();
     }
     
     // Update is called once per frame
     void Update () {
     
     }
 }

This gives me "The thing you want to instantiate is null." Same with built-in arrays. This is a blank script attached to stationary wall object. What obvious thing am I missing?