构建一个对应于Enumerable.Cast<T>的已编译委托？

using System;
using System.Collections;
using System.Linq.Expressions;

public class Program
{
    public static void Main()
    {
        // 构建一个对应于Enumerable.Cast<T>的已编译委托
        var castDelegate = BuildCastDelegate(typeof(int));

        // 测试已编译委托
        var list = new ArrayList { 1, 2, 3, "4", 5 };
        var castedList = castDelegate(list);

        foreach (var item in castedList)
        {
            Console.WriteLine(item);
        }
    }

    public static Func<IEnumerable, IEnumerable> BuildCastDelegate(Type targetType)
    {
        var sourceParam = Expression.Parameter(typeof(IEnumerable));
        var castMethod = typeof(Enumerable).GetMethod("Cast").MakeGenericMethod(targetType);
        var castExpression = Expression.Call(castMethod, sourceParam);
        var lambdaExpression = Expression.Lambda<Func<IEnumerable, IEnumerable>>(castExpression, sourceParam);

        return lambdaExpression.Compile();
    }
}