隐式委托转换并不总是适用于另一个项目中的委托？

Question

  

可能重复：
  Compilation fails if delegate definitions is put in another project?

使用.NET 3.5 SP1和Visual Studio 2008

项目A和B，两个类库，A使用B. 在项目B中，我有以下内容：

public delegate void MyDelegate(object o1, EventArgs o2);
public delegate T MyUberDelegate<T>(MyDelegate myDelegate);

public class MyTestClass
{
    private MyUberDelegate<EventHandler> uberDelegate;
    public MyTestClass()
    {
        uberDelegate = h => (s, e) => h(s, e);
    }
}

编译，没问题。 （uberDelegate返回一个调用MyDelegate的EventHandler）

如果我将MyTestClass复制到项目A，我会收到以下编译错误：

Error   1   Cannot convert lambda expression to delegate type 'MyUberDelegate<System.EventHandler>' because some of the return types in the block are not implicitly convertible to the delegate return type
Error   2   Delegate 'MyDelegate' does not take '2' arguments

如果我改变MyTestClass以包含MyDelegate类型的字段，它确实有效：

public class MyTestClass
{
    private MyUberDelegate<EventHandler> uberDelegate;
    private MyDelegate myDelegate;

    public MyTestClass()
    {
        uberDelegate = h => (s, e) => h(s, e);
    }
}

为什么吗

编辑：Compilation fails if delegate definitions is put in another project?

的副本