小编cat*_*hei的帖子

我在实现无分配 Linq 时遇到了有趣的案例。当我稍微更改代码时，基准测试时间突然增加，我认为更改是微不足道的。我将范围缩小到这个测试代码：

    [Benchmark]
    public int ComparingGenericArgument1()
    {
        var comparer = new Wrap<int>(Comparer<int>.Default);
        return CompareSum<Wrap<int>>.Calc(10000, comparer);
    }

    [Benchmark]
    public int ComparingGenericArgument2()
    {
        var comparer = new Wrap<int, Comparer<int>>(Comparer<int>.Default);
        return CompareSum<Wrap<int, Comparer<int>>>.Calc(10000, comparer);
    }

    static class CompareSum<TComparer> where TComparer : struct, IComparer<int>
    {
        public static int Calc(int count, TComparer comparer)
        {
            int sum = 0;

            for (int i = 0; i < count; ++i)
            for (int j = 0; j < count; ++j)
                sum += comparer.Compare(i, j);

            return sum;
        }
    } …