为什么当It.Is.()从匿名函数调用时，Moq设置/验证匹配器失败

在试图简化Setup/Verify匹配moq的复杂表达式树的创建时，我遇到了一些奇怪的行为。

假设我正在模拟下面定义的简单接口

public interface IService
{
    int Send(int value);
}

下面的代码代表5个测试。对每个mockSender.Setup(...)进行一次测试。谁能解释一下为什么标为不合格的测试确实不合格?

[Test]
public void TestInlineSetup()
{
    const int expected = 5;
    var mockSender = new Mock<IService>(MockBehavior.Loose);
    //passes
    mockSender.Setup(s => s.Send(It.IsAny<int>())).Returns(expected);
    //fails
    var sendMatch = It.IsAny<int>();
    mockSender.Setup(s => s.Send(sendMatch)).Returns(expected);
    //passes
    mockSender.Setup(s => s.Send(SendMatchFromMethod())).Returns(expected);
    //fails
    var sendMatch = SendMatchFromMethod();
    mockSender.Setup(s => s.Send(sendMatch)).Returns(expected);
    //fails (this is somewhat contrived, but I have reasons for wanting to curry this)
    mockSender.Setup(s => s.Send(SendMatchFromCurriedMethod()())).Returns(expected);
    Assert.That(mockSender.Object.Send(expected), Is.EqualTo(expected));
}
public static int SendMatchFromMethod()
{
    return It.IsAny<int>();
}
public static Func<int> SendMatchFromCurriedMethod()
{
    return () => It.IsAny<int>();
}

编辑:我知道Mock.Of<…>(…)，通常更喜欢使用它，但在这种情况下，它不是一个选项。