十六进制网格 A* 寻路..类型参数错误

我是一个崭露头角的编程爱好者和游戏设计师，正在学习完成我的学位，因此在编程领域仍然很陌生。我已经做了相当多的JavaScript（实际上是UnityScript），现在正在尝试涉足C#。我一直在遵循 hakimio 在 Unity 中制作回合制 RPG 的教程，该教程基于 A* 寻路的六边形网格。（http://tbswithunity3d.wordpress.com/）

我的问题是，我已经按照他的教程逐步完成 A* 寻路脚本和资源，但在 Unity 中遇到了错误：

"错误 CS0308：非泛型类型'IHasNeighbors' 不能与类型参数一起使用"

这是触发错误消息的代码，在第 public class Tile: GridObject, IHasNeighbours<Tile> 行：

using System.Collections.Generic;
using System;
using System.Linq;
using UnityEngine;
public class Tile: GridObject, IHasNeighbours<Tile>
{
public bool Passable;
public Tile(int x, int y)
    : base(x, y)
{
    Passable = true;
}
public IEnumerable AllNeighbours { get; set; }
public IEnumerable Neighbours
{
    get { return AllNeighbours.Where(o => o.Passable); }
}
public static List<Point> NeighbourShift
{
    get
    {
        return new List<Point>
        {
            new Point(0, 1),
            new Point(1, 0),
            new Point(1, -1),
            new Point(0, -1),
            new Point(-1, 0),
            new Point(-1, 1),
        };
    }
}
public void FindNeighbours(Dictionary<Point, Tile> Board, Vector2 BoardSize, bool EqualLineLengths)
{
    List<Tile> neighbours = new List<Tile>();
    foreach (Point point in NeighbourShift)
    {
        int neighbourX = X + point.X;
        int neighbourY = Y + point.Y;
        //x coordinate offset specific to straight axis coordinates
        int xOffset = neighbourY / 2;
        //if every second hexagon row has less hexagons than the first one, just skip the last one when we come to it
        if (neighbourY % 2 != 0 && !EqualLineLengths && neighbourX + xOffset == BoardSize.x - 1)
            continue;
        //check to determine if currently processed coordinate is still inside the board limits
        if (neighbourX >= 0 - xOffset &&
            neighbourX < (int)BoardSize.x - xOffset &&
            neighbourY >= 0 && neighbourY < (int)BoardSize.y)
            neighbours.Add(Board[new Point(neighbourX, neighbourY)]);
    }
    AllNeighbours = neighbours;
}
}

有关如何克服此错误的任何帮助或见解将不胜感激，过去几天我一直在努力尝试使其工作，并且无法继续教程（和我的项目）错误。

提前感谢大家！

亚伦·:)