Nullable suppression for Assert.Throws does not work in presence of a Assert.Multiple block

[smkanadl]

With regards to #333, I understand that the supression does not work inside an Assert.Multiple block. But I would have expect the following scenario to work, which I typically use for such cases.

var e = Assert.Throws<Exception>(() => throw new Exception("Test"));
Assert.Multiple(() =>
{
    Assert.That(e.Message, Is.EqualTo("Test'")); // I see a warning here that e might be null
    Assert.That(e.InnerException, Is.Null);
    Assert.That(e.StackTrace, Is.Not.Empty);
});

If I remove the Assert.Multiple block, the warning is correctly suppressed.

var e = Assert.Throws<Exception>(() => throw new Exception("Test"));
Assert.That(e.Message, Is.EqualTo("Test'")); // no warning now
Assert.That(e.InnerException, Is.Null);
Assert.That(e.StackTrace, Is.Not.Empty);

Is this some limitation that could be removed?
I am using the 3.0 Version in Visual Studio 2019 Preview 16.9

[mikkelbu]

Without looking at the code I think we should be able to determine that the assignment happens outside the Assert.Multiple, but I'm unsure how much this will complicate the code.

[manfred-brands]

Roslyn raises the 'possible null reference exception' on the line Assert.That(e.Message, Is.EqualTo("Test'"));.
The code then determines that this line is inside the Assert.Multiple and stops any search for the assignment and hence doesn't suppress. I will see if I can update the code to search for the assignment regardless.
@mikkelbu Please assign the ticket to me.

[smkanadl]

@manfred-brands that would be great if it could be improved that way. Thanks for taking care!

[mikkelbu]

Thanks @manfred-brands 👍