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

Unboxing a possibly null value.

Dereference of a possibly null reference.

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

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

Possible null reference return.

Nullability of type of parameter 'existingValue' doesn't match overridden member (possibly because of nullability attributes).

Nullability of type of parameter 'value' doesn't match overridden member (possibly because of nullability attributes).

The type name 'utils' only contains lower-cased ascii characters. Such names may become reserved for the language.