Callback validation too strict when setting up a task's .Result property

[stakx]

public interface IFoo
{
	Task<string> GetNameAsync();
}

var mock = new Mock<IFoo>();
mock.Setup(m => m.GetNameAsync().Result).Returns("Bob");
mock.Setup(m => m.GetNameAsync().Result).Returns(() => "Bob");

Both of these setups should work. In practice, however, only the first one will succeed, and the second one will fail with a callback validation error:

System.ArgumentException: Invalid callback. Setup on method with return type (System.Threading.Tasks.Task`1[System.String]) cannot invoke callback with return type (System.String).

(As an aside, we could format the type names in that error message nicer, too.)