NUnit2022 false-positive on generic Dictionary type

[yaakov-h]

IDictionary<TKey, TValue> implements ICollection<KeyValuePair<TKey, TValue>> and therefore has a Count property.

The code in the screenshot can be found here:

https://github.com/SteamDatabase/ValveKeyValue/blob/a4cef9a8aacdfb92491314176216bf11a4b4cfc0/ValveKeyValue/ValveKeyValue.Test/Text/StronglyTypedCollectionDeserializationTestCase.cs#L24-L43

[manfred-brands]

Is it only the analyser?
If you suppress NUnit2022 does the actual NUnit engine run fine?

[yaakov-h]

Yep, the test passes.

[manfred-brands]

The issue seems to be with the generic parameter constraint.

This does not raise NUnit2022:

[Test]
public void TestCollectionMethod()
{
    IDictionary<int, int> actual = new Dictionary<int, int>() { [1] = 1, [2] = 2 };

    AssertCollectionCount(actual);
    AssertCollectionCount(actual.Values);
    AssertCollectionCount(actual.Keys);

    static void AssertCollectionCount<T>(ICollection<T> instance)
    {
        Assert.That(instance, Has.Count.EqualTo(2));
    }
}

But this version does:

[Test]
public void TestGenericMethod()
{
    IDictionary<int, int> actual = new Dictionary<int, int>() { [1] = 1, [2] = 2 };

    AssertCollectionOfIntCount(actual.Values);
    AssertCollectionOfIntCount(actual.Keys);

    static void AssertCollectionOfIntCount<T>(T instance)
        where T : ICollection<int>
    {
        Assert.That(instance, Has.Count.EqualTo(2));
    }
}

So it seems we are not checking constraints.