Possible null reference return.

Non-nullable field '_itemList' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable property 'Foo' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Non-nullable property 'Foo' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the property as nullable.

Converting null literal or possible null value to non-nullable type.

Converting null literal or possible null value to non-nullable type.

Converting null literal or possible null value to non-nullable type.

Converting null literal or possible null value to non-nullable type.

Possible null reference argument for parameter 'source' in 'bool Enumerable.Any<(ILearningWorldViewModel, ILearningElementViewModel)>(IEnumerable<(ILearningWorldViewModel, ILearningElementViewModel)> source, Func<(ILearningWorldViewModel, ILearningElementViewModel), bool> predicate)'.